TPM1

UniProt ID: P09493
Organism: Homo sapiens
Review Status: INITIALIZED
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Gene Description

TPM1 (Tropomyosin 1) is a coiled-coil actin-binding protein with 10 tissue-specific isoforms. ISOFORM BIOLOGY: (1) Isoform 1 (TPM1alpha, P09493-1) is expressed in SKELETAL MUSCLE; (2) Isoform 2 is SMOOTH MUSCLE-specific; (3) Isoform 3 (TM3) is the FIBROBLAST/cytoskeletal form; (4) Isoform 6 (TPM1kappa) is CARDIAC-specific. UniProt states "Isoform 1 is expressed in adult and fetal skeletal muscle and cardiac tissues. Isoform 10 is expressed in adult and fetal cardiac tissues, but not in skeletal muscle." Muscle isoforms regulate actin-myosin interaction in sarcomeres; cytoskeletal isoforms organize non-muscle actin. DISEASE: Mutations cause cardiomyopathy (CMH3, CMD1Y) affecting sarcomere function. Annotations for "muscle contraction" and "sarcomere" apply primarily to muscle isoforms, while "cytoskeleton organization" applies more to non-muscle isoforms.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0051015 actin filament binding
IBA
GO_REF:0000033
ACCEPT
Summary: Core function of all TPM1 isoforms. Tropomyosin binds along the length of actin filaments in both muscle and non-muscle cells. UniProt states that TPM1 binds to actin filaments. This function is conserved across all isoforms - muscle isoforms bind thin filament actin while cytoskeletal isoforms bind stress fiber actin.
Reason: Actin filament binding is the fundamental molecular function of all tropomyosins. IBA annotation is appropriate as this function is phylogenetically conserved. Supported by functional studies showing TPM1 binds actin filaments in both muscle and non-muscle contexts [PMID:12686598].
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
PMID:8205619
alpha-tropomyosin and cardiac troponin T as well as beta myosin heavy chain mutations cause the same phenotype, we conclude that FHC is a disease of the sarcomere
GO:0007015 actin filament organization
IBA
GO_REF:0000033
ACCEPT
Summary: TPM1 plays a role in actin filament organization in both muscle and non-muscle cells. In muscle, it organizes thin filaments; in non-muscle cells, it contributes to stress fiber formation and cytoskeletal organization [PMID:12686598].
Reason: Actin filament organization is a core function of tropomyosins across all isoforms. Muscle isoforms organize thin filaments in sarcomeres; cytoskeletal isoforms stabilize stress fibers in non-muscle cells. IBA annotation is appropriate.
Supporting Evidence:
PMID:12686598
phosphorylation of tropomyosin-1 downstream of ERK by contributing to formation of actin filaments increases cellular contractility and promotes the formation of focal adhesions
PMID:15897890
TGF-beta induction of stress fibers in epithelial cells requires high molecular weight tropomyosins encoded by TPM1 and TPM2 genes
GO:0005884 actin filament
IBA
GO_REF:0000033
ACCEPT
Summary: TPM1 localizes to actin filaments in both muscle and non-muscle cells. This cellular component annotation reflects the physical location of tropomyosin bound along actin filaments.
Reason: Tropomyosin is an integral component of actin filaments. In muscle cells it forms the thin filament regulatory complex; in non-muscle cells it associates with stress fibers and other actin structures. IBA annotation is appropriate.
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
GO:0060048 cardiac muscle contraction
IBA
GO_REF:0000033
ACCEPT
Summary: ISOFORM-SPECIFIC: Cardiac muscle contraction is a function of the striated muscle isoforms (Isoform 1/TPM1alpha and Isoform 6/TPM1kappa). UniProt states Isoform 1 is expressed in cardiac tissues and Isoform 6 is cardiac-specific. Mutations cause cardiomyopathy (CMH3, CMD1Y) [PMID:8205619, PMID:11273725].
Reason: This is a core function for cardiac isoforms. TPM1 plays a central role in calcium-dependent regulation of cardiac muscle contraction via the troponin complex. Mutations affecting this function cause hypertrophic and dilated cardiomyopathy, demonstrating its importance [PMID:8205619]. IBA annotation is appropriate as this function is conserved in striated muscle isoforms.
Supporting Evidence:
PMID:8205619
We demonstrate that missense mutations (Asp175Asn; Glu180Gly) in the alpha-tropomyosin gene cause familial hypertrophic cardiomyopathy (FHC)
PMID:11136687
HCM was linked to the TPM1 gene... The mutation caused a 40% to 50% increase in calcium affinity in regulated thin filament-myosin subfragment-1 (S1) MgATPase assays
GO:0003779 actin binding
IEA
GO_REF:0000043
ACCEPT
Summary: Actin binding is the fundamental molecular function of all tropomyosins. This IEA annotation based on UniProt keyword mapping is correct but less specific than GO:0051015 (actin filament binding) which is already annotated via IBA.
Reason: While this is a broader parent term of actin filament binding, it is still correct. IEA annotations at a broader level are acceptable alongside more specific experimental annotations. No action needed as the more specific IBA annotation (GO:0051015) captures the precise function.
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
GO:0005856 cytoskeleton
IEA
GO_REF:0000044
ACCEPT
Summary: TPM1 is a cytoskeletal protein. UniProt subcellular location indicates "Cytoplasm, cytoskeleton" and notes it "Associates with F-actin stress fibers." This is a broad cellular component annotation appropriate for all isoforms.
Reason: This is a valid broad localization term. All TPM1 isoforms are components of the cytoskeleton, whether in sarcomeres (muscle isoforms) or stress fibers (non-muscle isoforms). IEA based on UniProt subcellular location is appropriate.
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
GO:0005862 muscle thin filament tropomyosin
IEA
GO_REF:0000117
ACCEPT
Summary: ISOFORM-SPECIFIC: This cellular component term is specifically for muscle isoforms (Isoform 1/skeletal, Isoform 2/smooth, Isoform 6/cardiac). The muscle thin filament tropomyosin complex contains tropomyosin bound to actin filaments in sarcomeres. Non-muscle isoforms (e.g., Isoform 3/fibroblast) do not form this specific complex.
Reason: This is a core localization for muscle isoforms of TPM1. The annotation is correct for the muscle-expressed isoforms that are integral to the thin filament regulatory complex in sarcomeres [PMID:8205619].
Supporting Evidence:
PMID:8205619
FHC is a disease of the sarcomere
PMID:11136687
regulated thin filament-myosin subfragment-1 (S1) MgATPase assays
GO:0005515 protein binding
IPI
PMID:16189514
Towards a proteome-scale map of the human protein-protein in...
MARK AS OVER ANNOTATED
Summary: High-throughput Y2H interactome study. The term "protein binding" is uninformative and does not indicate specific binding partners or functional context. TPM1 binds actin, troponins, and other muscle/cytoskeletal proteins, but this generic term does not capture those specific interactions.
Reason: "Protein binding" (GO:0005515) is an uninformative annotation that does not convey the specific molecular interactions of TPM1 (e.g., actin binding, troponin complex binding). High-throughput interactome studies often generate these generic annotations. More specific MF terms are preferred [PMID:16189514].
Supporting Evidence:
PMID:16189514
Using a stringent, high-throughput yeast two-hybrid system, we tested pairwise interactions among the products of approximately 8,100 currently available Gateway-cloned open reading frames and detected approximately 2,800 interactions
GO:0005515 protein binding
IPI
PMID:21516116
Next-generation sequencing to generate interactome datasets.
MARK AS OVER ANNOTATED
Summary: High-throughput Stitch-seq Y2H interactome study. The generic term "protein binding" is uninformative for this well-characterized actin-binding protein.
Reason: "Protein binding" (GO:0005515) from high-throughput interactome studies is too generic. TPM1 has specific, well-characterized binding partners (actin, troponins, LMOD2, TMOD1) that are more informative [PMID:21516116].
Supporting Evidence:
PMID:21516116
We describe a massively parallel interactome-mapping pipeline, Stitch-seq, that combines PCR stitching with next-generation sequencing and used it to generate a new human interactome dataset
GO:0005515 protein binding
IPI
PMID:25416956
A proteome-scale map of the human interactome network.
MARK AS OVER ANNOTATED
Summary: Large-scale proteome-scale human interactome map study. Generic "protein binding" term is uninformative for TPM1 which has well-characterized specific interactions.
Reason: "Protein binding" (GO:0005515) from systematic interactome mapping is too generic. TPM1 has specific, functionally important binding partners that should be annotated instead [PMID:25416956].
Supporting Evidence:
PMID:25416956
Here, we describe a systematic map of ?14,000 high-quality human binary protein-protein interactions
GO:0005515 protein binding
IPI
PMID:26871637
Widespread Expansion of Protein Interaction Capabilities by ...
MARK AS OVER ANNOTATED
Summary: Study on alternative splicing and protein interaction capabilities. Notably relevant for TPM1 which has 10 isoforms with different interaction profiles. However "protein binding" remains uninformative.
Reason: While this study is highly relevant to TPM1 isoform biology, showing that alternative isoforms exhibit different interaction profiles, the generic "protein binding" term does not capture the specific binding partners or isoform-specific interactions [PMID:26871637].
Supporting Evidence:
PMID:26871637
The majority of isoform pairs share less than 50% of their interactions. In the global context of interactome network maps, alternative isoforms tend to behave like distinct proteins rather than minor variants of each other
GO:0005515 protein binding
IPI
PMID:30021884
Histone Interaction Landscapes Visualized by Crosslinking Ma...
MARK AS OVER ANNOTATED
Summary: Crosslinking mass spectrometry study of histone interactions in nuclei. TPM1 is a cytoplasmic/cytoskeletal protein; its detection here may be incidental. Generic "protein binding" term is uninformative.
Reason: "Protein binding" from crosslinking MS study of nuclear proteins is not informative for TPM1, which is primarily a cytoskeletal protein. The generic term provides no functional insight [PMID:30021884].
Supporting Evidence:
PMID:30021884
Here we use crosslinking mass spectrometry (XL-MS) to chart the protein-protein interactions in intact human nuclei
GO:0005515 protein binding
IPI
PMID:33961781
Dual proteome-scale networks reveal cell-specific remodeling...
MARK AS OVER ANNOTATED
Summary: BioPlex 3.0 dual proteome-scale network study in 293T and HCT116 cells. While this reveals cell-specific interactome remodeling relevant to TPM1 isoforms, the generic "protein binding" term is uninformative.
Reason: "Protein binding" from large-scale AP-MS interactome study does not provide specific information about TPM1's functional binding partners. More specific terms for actin binding, troponin binding etc. are preferred [PMID:33961781].
Supporting Evidence:
PMID:33961781
Thousands of interactions assemble proteins into modules that impart spatial and functional organization to the cellular proteome
GO:0005515 protein binding
IPI
PMID:40205054
Multimodal cell maps as a foundation for structural and func...
MARK AS OVER ANNOTATED
Summary: Multimodal cell maps study integrating multiple data types for structural and functional genomics. Generic "protein binding" term is uninformative.
Reason: "Protein binding" from multimodal cell mapping study does not convey specific information about TPM1's well-characterized binding partners [PMID:40205054].
Supporting Evidence:
PMID:40205054
Multimodal cell maps as a foundation for structural and functional genomics
GO:0005515 protein binding
IPI
P09493-10
PMID:25910212
Widespread macromolecular interaction perturbations in human...
MARK AS OVER ANNOTATED
Summary: ISOFORM-SPECIFIC ANNOTATION (P09493-10). Study on macromolecular interaction perturbations in genetic disorders. While highly relevant to understanding how TPM1 mutations affect interactions, "protein binding" is uninformative.
Reason: "Protein binding" from edgetic mutation studies is too generic. This study shows disease mutations can perturb specific interactions, but the annotation lacks specificity about which interactions [PMID:25910212].
Supporting Evidence:
PMID:25910212
While common variants from healthy individuals rarely affect interactions, two-thirds of disease-associated alleles perturb protein-protein interactions, with half corresponding to "edgetic" alleles affecting only a subset of interactions while leaving most other interactions unperturbed
GO:0005515 protein binding
IPI
P09493-10
PMID:32296183
A reference map of the human binary protein interactome.
MARK AS OVER ANNOTATED
Summary: ISOFORM-SPECIFIC ANNOTATION (P09493-10). HuRI reference human binary protein interactome map. While highly valuable for mapping interactions, the generic "protein binding" term is uninformative for TPM1.
Reason: "Protein binding" from the comprehensive HuRI interactome map does not convey specific binding partners. TPM1 has well-characterized interactions with actin, troponins, and other thin filament proteins that are more informative [PMID:32296183].
Supporting Evidence:
PMID:32296183
Here we present a human 'all-by-all' reference interactome map of human binary protein interactions, or 'HuRI'
GO:0042802 identical protein binding
ISS
GO_REF:0000024
ACCEPT
Summary: Tropomyosins form coiled-coil dimers (homo- or heterodimers) as their functional unit. UniProt indicates TPM1 forms dimers with itself or other tropomyosin isoforms. This ISS annotation from sequence similarity is consistent with the coiled-coil structure of tropomyosins.
Reason: TPM1 forms parallel coiled-coil dimers that bind along actin filaments. This is a fundamental structural property of all tropomyosins. Self-association (homodimerization) is documented in UniProt. ISS annotation based on sequence similarity to characterized orthologs is appropriate.
GO:0042803 protein homodimerization activity
ISS
GO_REF:0000024
ACCEPT
Summary: Tropomyosins function as coiled-coil dimers. TPM1 homodimerizes to form the functional unit that binds along actin filaments. This is a core structural property of tropomyosins.
Reason: Homodimerization is fundamental to tropomyosin function. Two TPM1 chains form a parallel coiled-coil dimer that spans seven actin subunits. ISS annotation based on sequence similarity is appropriate for this conserved structural property.
GO:0046982 protein heterodimerization activity
ISS
GO_REF:0000024
ACCEPT
Summary: TPM1 can form heterodimers with other tropomyosin isoforms (e.g., TPM2, TPM3). UniProt indicates it interacts with self or TPM2. Heterodimer formation provides functional diversity in different tissue contexts.
Reason: Heterodimerization with other tropomyosin isoforms is a documented property that provides functional diversity. TPM1 can form dimers with TPM2 and potentially other isoforms. ISS annotation based on sequence similarity is appropriate.
GO:0051015 actin filament binding
ISS
GO_REF:0000024
ACCEPT
Summary: Duplicate of the IBA annotation for actin filament binding. This ISS annotation provides additional evidence for this core function from sequence similarity.
Reason: Actin filament binding is the fundamental molecular function of TPM1 across all isoforms. This ISS annotation supplements the IBA annotation and is consistent with the conserved function of tropomyosins.
GO:0008360 regulation of cell shape
IMP
PMID:21817107
MicroRNA-21 regulates vascular smooth muscle cell function v...
KEEP AS NON CORE
Summary: ISOFORM-SPECIFIC: This annotation relates to the cytoskeletal (non-muscle) function of TPM1 isoforms. The study shows TPM1 affects vascular smooth muscle cell morphology via cytoskeletal remodeling [PMID:21817107].
Reason: Regulation of cell shape is a function of cytoskeletal TPM1 isoforms in non-muscle cells. While important, it is not the core function of the striated muscle isoforms. This is a valid annotation for cytoskeletal isoforms [PMID:21817107].
Supporting Evidence:
PMID:21817107
cell proliferation and migration were significantly decreased by
GO:1904706 negative regulation of vascular associated smooth muscle cell proliferation
IMP
PMID:21817107
MicroRNA-21 regulates vascular smooth muscle cell function v...
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Summary: ISOFORM-SPECIFIC: TPM1 overexpression inhibits vascular smooth muscle cell (VSMC) proliferation. This relates to the cytoskeletal function of TPM1 in regulating cell behavior [PMID:21817107].
Reason: This is a valid functional annotation for cytoskeletal TPM1 isoforms in smooth muscle cells. While biologically relevant, it represents a peripheral function rather than the core sarcomeric function of TPM1 [PMID:21817107].
Supporting Evidence:
PMID:21817107
cell proliferation and migration were significantly decreased by
GO:1904753 negative regulation of vascular associated smooth muscle cell migration
IMP
PMID:21817107
MicroRNA-21 regulates vascular smooth muscle cell function v...
KEEP AS NON CORE
Summary: ISOFORM-SPECIFIC: TPM1 overexpression inhibits vascular smooth muscle cell (VSMC) migration. This relates to the cytoskeletal function of TPM1 in regulating cell motility [PMID:21817107].
Reason: This is a valid functional annotation for cytoskeletal TPM1 isoforms in smooth muscle cells. While biologically relevant, it represents a peripheral function rather than the core sarcomeric function of TPM1 [PMID:21817107].
Supporting Evidence:
PMID:21817107
cell proliferation and migration were significantly decreased by
GO:0005829 cytosol
TAS
Reactome:R-HSA-390593
ACCEPT
Summary: Reactome pathway annotation for muscle contraction. TPM1 is a cytosolic/ cytoskeletal protein that associates with actin filaments. Cytosol localization is valid for soluble tropomyosin before assembly.
Reason: Cytosol is an appropriate cellular component for TPM1. Prior to incorporation into actin filaments, tropomyosin exists in the cytosol. Reactome pathway annotations for muscle contraction support this localization.
GO:0005829 cytosol
TAS
Reactome:R-HSA-390595
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization in muscle contraction pathway.
Reason: Valid cellular component annotation from Reactome muscle contraction pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0005829 cytosol
TAS
Reactome:R-HSA-390597
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization.
Reason: Valid cellular component annotation from Reactome pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0005829 cytosol
TAS
Reactome:R-HSA-390598
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization.
Reason: Valid cellular component annotation from Reactome pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0005829 cytosol
TAS
Reactome:R-HSA-445699
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization.
Reason: Valid cellular component annotation from Reactome pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0005829 cytosol
TAS
Reactome:R-HSA-445700
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization.
Reason: Valid cellular component annotation from Reactome pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0005829 cytosol
TAS
Reactome:R-HSA-445704
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization.
Reason: Valid cellular component annotation from Reactome pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0005829 cytosol
TAS
Reactome:R-HSA-445705
ACCEPT
Summary: Duplicate Reactome pathway annotation for cytosol localization.
Reason: Valid cellular component annotation from Reactome pathway. Cytosol localization is appropriate for soluble tropomyosin.
GO:0008092 cytoskeletal protein binding
IPI
PMID:17987659
Nebulette interacts with filamin C.
ACCEPT
Summary: TPM1 binds cytoskeletal proteins including nebulette. The study identified tropomyosin-1 as a binding partner of nebulette in a yeast two-hybrid screen [PMID:17987659].
Reason: Cytoskeletal protein binding accurately describes TPM1's interactions with actin filaments and associated regulatory proteins. This is a valid molecular function annotation that is more specific than "protein binding".
Supporting Evidence:
PMID:17987659
Nebulette interacts with filamin C.
GO:0045214 sarcomere organization
IMP
PMID:11273725
Mutations that alter the surface charge of alpha-tropomyosin...
ACCEPT
Summary: ISOFORM-SPECIFIC: Sarcomere organization is a function of muscle isoforms. TPM1 mutations cause disorganized sarcomere structure in cardiomyopathy [PMID:11273725].
Reason: Sarcomere organization is a core function of striated muscle TPM1 isoforms. Mutations affecting this function cause hypertrophic and dilated cardiomyopathy. This is a well-supported experimental annotation [PMID:11273725].
Supporting Evidence:
PMID:11273725
Proteins in cardiac myocytes assemble into contractile units known as sarcomeres
GO:0001725 stress fiber
IDA
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
ACCEPT
Summary: ISOFORM-SPECIFIC: TPM1 localizes to stress fibers in non-muscle cells. The study shows TPM1 colocalizes with actin stress fibers upon stimulation [PMID:12686598].
Reason: Stress fiber localization is a valid cellular component annotation for cytoskeletal TPM1 isoforms (e.g., Isoform 3/TM3). IDA evidence from direct observation of colocalization with stress fibers [PMID:12686598].
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
GO:0003065 positive regulation of heart rate by epinephrine
ISS
PMID:17556658
Dilated cardiomyopathy mutant tropomyosin mice develop cardi...
KEEP AS NON CORE
Summary: ISOFORM-SPECIFIC: This relates to cardiac isoforms (TPM1alpha, TPM1kappa) and their role in beta-adrenergic signaling in the heart. Tropomyosin phosphorylation modulates cardiac contractility.
Reason: While TPM1 is involved in cardiac muscle contraction, the specific role in epinephrine-mediated heart rate regulation is indirect via modulation of thin filament Ca2+ sensitivity. This is a secondary function rather than a core molecular function.
Supporting Evidence:
PMID:17556658
2007 Jun 7. Dilated cardiomyopathy mutant tropomyosin mice develop cardiac dysfunction with significantly decreased fractional shortening and myofilament calcium sensitivity.
GO:0003779 actin binding
TAS
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
ACCEPT
Summary: Core function of TPM1. Actin binding is fundamental to all TPM1 isoforms. This TAS annotation based on literature review is consistent with the well-established role of tropomyosin [PMID:12686598].
Reason: Actin binding is the fundamental molecular function of tropomyosin. This annotation supplements the more specific "actin filament binding" term already annotated via IBA [PMID:12686598].
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
GO:0005200 structural constituent of cytoskeleton
TAS
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
ACCEPT
Summary: TPM1 is a structural component of the actin cytoskeleton in both muscle and non-muscle cells. In muscle cells it forms thin filaments; in non-muscle cells it stabilizes stress fibers [PMID:12686598].
Reason: Structural constituent of cytoskeleton is an accurate molecular function for TPM1. Tropomyosin provides structural stability to actin filaments and is integral to cytoskeletal architecture [PMID:12686598].
Supporting Evidence:
PMID:12686598
phosphorylation of tropomyosin-1 downstream of ERK by contributing to formation of actin filaments increases cellular contractility and promotes the formation of focal adhesions
GO:0007010 cytoskeleton organization
TAS
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
ACCEPT
Summary: TPM1 contributes to cytoskeleton organization in both muscle and non-muscle cells. This is closely related to actin filament organization [PMID:12686598].
Reason: Cytoskeleton organization is a core function of TPM1 across all isoforms. In muscle, it organizes sarcomere thin filaments; in non-muscle cells, it contributes to stress fiber organization [PMID:12686598].
Supporting Evidence:
PMID:12686598
phosphorylation of tropomyosin-1 downstream of ERK by contributing to formation of actin filaments increases cellular contractility and promotes the formation of focal adhesions
GO:0030049 muscle filament sliding
ISS
PMID:11136687
Hypertrophic cardiomyopathy caused by a novel alpha-tropomyo...
ACCEPT
Summary: ISOFORM-SPECIFIC: Muscle filament sliding is a function of striated muscle isoforms. TPM1 regulates the interaction between thin and thick filaments during muscle contraction [PMID:11136687].
Reason: Muscle filament sliding is a core function of muscle TPM1 isoforms. Tropomyosin regulates the actin-myosin interaction that drives filament sliding during contraction. Mutations affecting this cause cardiomyopathy [PMID:11136687].
Supporting Evidence:
PMID:11136687
The mutation caused a 40% to 50% increase in calcium affinity in regulated thin filament-myosin subfragment-1 (S1) MgATPase assays
GO:0030336 negative regulation of cell migration
ISS
PMID:15897890
Silencing of the Tropomyosin-1 gene by DNA methylation alter...
KEEP AS NON CORE
Summary: ISOFORM-SPECIFIC: Cytoskeletal TPM1 isoforms regulate cell migration. High molecular weight tropomyosins stabilize stress fibers and inhibit cell motility [PMID:15897890].
Reason: Regulation of cell migration is a function of cytoskeletal TPM1 isoforms in non-muscle cells. While valid, this is a peripheral function related to the core actin-binding activity [PMID:15897890].
Supporting Evidence:
PMID:15897890
TGF-beta induction of stress fibers in epithelial cells requires high molecular weight tropomyosins encoded by TPM1 and TPM2 genes
GO:0031529 ruffle organization
ISS
PMID:15897890
Silencing of the Tropomyosin-1 gene by DNA methylation alter...
KEEP AS NON CORE
Summary: ISOFORM-SPECIFIC: TPM1 affects membrane ruffle organization in non-muscle cells. This relates to cytoskeletal actin dynamics [PMID:15897890].
Reason: Ruffle organization is a function of cytoskeletal TPM1 isoforms in non-muscle cells. This is a peripheral function related to the core actin-organizing activity [PMID:15897890].
Supporting Evidence:
PMID:15897890
TGF-beta induction of stress fibers in epithelial cells requires high molecular weight tropomyosins encoded by TPM1 and TPM2 genes
IMP
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
KEEP AS NON CORE
Summary: TPM1 localizes to membrane blebs in response to oxidative stress. This relates to cytoskeletal reorganization during stress responses [PMID:12686598].
Reason: Bleb localization is a peripheral cellular component annotation related to stress responses rather than core TPM1 function [PMID:12686598].
Supporting Evidence:
PMID:12686598
presence of H(2)O(2) resulted in a quick and intense membrane blebbing
GO:0032587 ruffle membrane
IDA
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
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Summary: ISOFORM-SPECIFIC: TPM1 localizes to ruffle membranes in non-muscle cells. This relates to cytoskeletal actin dynamics at the cell periphery [PMID:12686598].
Reason: Ruffle membrane localization is a cellular component for cytoskeletal TPM1 isoforms in non-muscle cells. This is a peripheral localization related to actin dynamics [PMID:12686598].
Supporting Evidence:
PMID:12686598
tropomyosin-1 was found diffuse in the cells, whereas it quickly colocalized with actin and stress fibers upon stimulation
GO:0034614 cellular response to reactive oxygen species
IEP
PMID:12686598
Extracellular signal-regulated kinase mediates phosphorylati...
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Summary: TPM1 is phosphorylated in response to oxidative stress via ERK signaling. This leads to cytoskeletal remodeling and affects membrane dynamics [PMID:12686598].
Reason: Response to ROS is a peripheral function related to stress-induced cytoskeletal remodeling. TPM1 phosphorylation downstream of ERK modulates stress fiber formation during oxidative stress [PMID:12686598].
Supporting Evidence:
PMID:12686598
phosphorylation of tropomyosin-1 downstream of ERK by contributing to formation of actin filaments increases cellular contractility and promotes the formation of focal adhesions
GO:0042060 wound healing
ISS
PMID:17721995
Role of high-molecular weight tropomyosins in TGF-beta-media...
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Summary: ISOFORM-SPECIFIC: TPM1 is involved in wound healing through its role in cytoskeletal remodeling and cell migration during tissue repair [PMID:17721995].
Reason: Wound healing is a peripheral function of cytoskeletal TPM1 isoforms related to cell migration and tissue remodeling. While biologically relevant, this is not a core molecular function [PMID:17721995].
Supporting Evidence:
PMID:17721995
HMW-tropomyosins are important for TGF-beta-mediated control of cell
GO:0045785 positive regulation of cell adhesion
ISS
PMID:17721995
Role of high-molecular weight tropomyosins in TGF-beta-media...
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Summary: ISOFORM-SPECIFIC: TPM1 promotes cell adhesion by enhancing actin stress fibers and focal adhesions in non-muscle cells [PMID:17721995].
Reason: Regulation of cell adhesion is a peripheral function of cytoskeletal TPM1 isoforms related to stress fiber stabilization [PMID:17721995].
Supporting Evidence:
PMID:17721995
Tropomyosin increased cell adhesion to matrix by enhancing actin fibers and focal adhesions
GO:0051496 positive regulation of stress fiber assembly
ISS
PMID:15897890
Silencing of the Tropomyosin-1 gene by DNA methylation alter...
ACCEPT
Summary: ISOFORM-SPECIFIC: TPM1 (HMW tropomyosins) are required for TGF-beta-induced stress fiber assembly in epithelial cells [PMID:15897890].
Reason: Positive regulation of stress fiber assembly is a well-documented function of cytoskeletal TPM1 isoforms. HMW tropomyosins stabilize and promote stress fiber formation [PMID:15897890].
Supporting Evidence:
PMID:15897890
TGF-beta induction of stress fibers in epithelial cells requires high molecular weight tropomyosins encoded by TPM1 and TPM2 genes
GO:0055010 ventricular cardiac muscle tissue morphogenesis
IMP
PMID:11136687
Hypertrophic cardiomyopathy caused by a novel alpha-tropomyo...
KEEP AS NON CORE
Summary: ISOFORM-SPECIFIC: Cardiac TPM1 isoforms are essential for ventricular morphogenesis. Mutations cause hypertrophic cardiomyopathy with ventricular hypertrophy [PMID:11136687].
Reason: Ventricular morphogenesis is a developmental process that TPM1 mutations affect. While important, this is a downstream consequence of TPM1's role in cardiac muscle function rather than a core molecular function [PMID:11136687].
Supporting Evidence:
PMID:11136687
The mutation caused a 40% to 50% increase in calcium affinity in regulated thin filament-myosin subfragment-1 (S1) MgATPase assays
GO:0060048 cardiac muscle contraction
IMP
PMID:11136687
Hypertrophic cardiomyopathy caused by a novel alpha-tropomyo...
ACCEPT
Summary: ISOFORM-SPECIFIC: This IMP annotation with experimental evidence complements the IBA annotation for cardiac muscle contraction. TPM1 mutations affect Ca2+ sensitivity and muscle contraction [PMID:11136687].
Reason: Cardiac muscle contraction is a core function of cardiac TPM1 isoforms. This experimental annotation provides direct evidence that TPM1 mutations affect cardiac contractile function [PMID:11136687].
Supporting Evidence:
PMID:11136687
The mutation caused a 40% to 50% increase in calcium affinity in regulated thin filament-myosin subfragment-1 (S1) MgATPase assays
GO:0030017 sarcomere
TAS
PMID:16754800
Single-gene mutations and increased left ventricular wall th...
ACCEPT
Summary: ISOFORM-SPECIFIC: Sarcomere localization is specific to striated muscle TPM1 isoforms. TPM1 is an integral component of thin filaments in sarcomeres.
Reason: Sarcomere is a core cellular component for muscle TPM1 isoforms. Tropomyosin is an integral part of the thin filament in sarcomeric structures. TAS annotation from literature supports this well-established localization.
Supporting Evidence:
PMID:16754800
Single-gene mutations and increased left ventricular wall thickness in the community: the Framingham Heart Study.
GO:0005856 cytoskeleton
TAS
PMID:16130169
Proteomics of human umbilical vein endothelial cells applied...
ACCEPT
Summary: TPM1 is a cytoskeletal protein identified in proteomic studies of endothelial cells. This annotation complements the IEA cytoskeleton annotation.
Reason: Cytoskeleton is a valid cellular component for TPM1. All isoforms are components of the cytoskeleton, whether in sarcomeres or stress fibers. TAS annotation is appropriate.
Supporting Evidence:
PMID:16130169
Proteomics of human umbilical vein endothelial cells applied to etoposide-induced apoptosis.
GO:0005862 muscle thin filament tropomyosin
TAS
PMID:8205619
Alpha-tropomyosin and cardiac troponin T mutations cause fam...
ACCEPT
Summary: ISOFORM-SPECIFIC: This TAS annotation complements the IEA annotation for muscle thin filament tropomyosin. TPM1 mutations in this complex cause familial hypertrophic cardiomyopathy [PMID:8205619].
Reason: Muscle thin filament tropomyosin is a core cellular component for muscle TPM1 isoforms. The cited study demonstrates TPM1's role in the thin filament complex and disease consequences of mutations [PMID:8205619].
Supporting Evidence:
PMID:8205619
alpha-tropomyosin and cardiac troponin T as well as beta myosin heavy chain mutations cause the same phenotype, we conclude that FHC is a disease of the sarcomere
GO:0006937 regulation of muscle contraction
TAS
PMID:3336363
Human hTM alpha gene: expression in muscle and nonmuscle tis...
ACCEPT
Summary: ISOFORM-SPECIFIC: Regulation of muscle contraction is a core function of muscle TPM1 isoforms. The study describes expression of alpha-tropomyosin in muscle and non-muscle tissues.
Reason: Regulation of muscle contraction is a core biological process for muscle TPM1 isoforms. Tropomyosin regulates actin-myosin interaction in a Ca2+-dependent manner via the troponin complex. TAS annotation is appropriate.
Supporting Evidence:
PMID:3336363
Human hTM alpha gene: expression in muscle and nonmuscle tissue.
GO:0008016 regulation of heart contraction
TAS
PMID:8205619
Alpha-tropomyosin and cardiac troponin T mutations cause fam...
ACCEPT
Summary: ISOFORM-SPECIFIC: Cardiac TPM1 isoforms regulate heart contraction. Mutations cause familial hypertrophic cardiomyopathy, demonstrating the essential role of TPM1 in cardiac function [PMID:8205619].
Reason: Regulation of heart contraction is a core function of cardiac TPM1 isoforms. Mutations affecting this function cause cardiomyopathy [PMID:8205619].
Supporting Evidence:
PMID:8205619
We demonstrate that missense mutations (Asp175Asn; Glu180Gly) in the alpha-tropomyosin gene cause familial hypertrophic cardiomyopathy (FHC)
GO:0008307 structural constituent of muscle
TAS
PMID:8205619
Alpha-tropomyosin and cardiac troponin T mutations cause fam...
ACCEPT
Summary: ISOFORM-SPECIFIC: Muscle TPM1 isoforms are structural constituents of muscle thin filaments in sarcomeres [PMID:8205619].
Reason: Structural constituent of muscle is a core molecular function for muscle TPM1 isoforms. TPM1 is an integral structural component of thin filaments in sarcomeres [PMID:8205619].
Supporting Evidence:
PMID:8205619
alpha-tropomyosin and cardiac troponin T as well as beta myosin heavy chain mutations cause the same phenotype, we conclude that FHC is a disease of the sarcomere

Core Functions

Actin filament binding is the fundamental molecular function of all TPM1 isoforms. Tropomyosin dimers bind along the length of actin filaments in both muscle (thin filaments) and non-muscle (stress fibers) cells, stabilizing actin filaments and regulating their interactions with other proteins.

Molecular Function:
actin filament binding
Directly Involved In:
Cellular Locations:

ISOFORM-SPECIFIC (Cardiac isoforms): Cardiac muscle contraction is a core function of striated muscle isoforms (TPM1alpha, TPM1kappa). TPM1 regulates calcium-dependent actin-myosin interaction via the troponin complex. Mutations cause cardiomyopathy (CMH3, CMD1Y).

ISOFORM-SPECIFIC (Cytoskeletal isoforms): Non-muscle TPM1 isoforms (e.g., TM3) bind actin filaments in stress fibers and contribute to cytoskeletal organization, cell shape regulation, and cell motility.

References

Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Electronic Gene Ontology annotations created by ARBA machine learning models
Hypertrophic cardiomyopathy caused by a novel alpha-tropomyosin mutation (V95A) is associated with mild cardiac phenotype, abnormal calcium binding to troponin, abnormal myosin cycling, and poor prognosis.
Mutations that alter the surface charge of alpha-tropomyosin are associated with dilated cardiomyopathy.
Extracellular signal-regulated kinase mediates phosphorylation of tropomyosin-1 to promote cytoskeleton remodeling in response to oxidative stress: impact on membrane blebbing.
Silencing of the Tropomyosin-1 gene by DNA methylation alters tumor suppressor function of TGF-beta.
Proteomics of human umbilical vein endothelial cells applied to etoposide-induced apoptosis.
Towards a proteome-scale map of the human protein-protein interaction network.
Single-gene mutations and increased left ventricular wall thickness in the community: the Framingham Heart Study.
Dilated cardiomyopathy mutant tropomyosin mice develop cardiac dysfunction with significantly decreased fractional shortening and myofilament calcium sensitivity.
Role of high-molecular weight tropomyosins in TGF-beta-mediated control of cell motility.
Nebulette interacts with filamin C.
Next-generation sequencing to generate interactome datasets.
MicroRNA-21 regulates vascular smooth muscle cell function via targeting tropomyosin 1 in arteriosclerosis obliterans of lower extremities.
A proteome-scale map of the human interactome network.
Widespread macromolecular interaction perturbations in human genetic disorders.
Widespread Expansion of Protein Interaction Capabilities by Alternative Splicing.
Histone Interaction Landscapes Visualized by Crosslinking Mass Spectrometry in Intact Cell Nuclei.
A reference map of the human binary protein interactome.
Human hTM alpha gene: expression in muscle and nonmuscle tissue.
Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.
Multimodal cell maps as a foundation for structural and functional genomics.
Alpha-tropomyosin and cardiac troponin T mutations cause familial hypertrophic cardiomyopathy: a disease of the sarcomere.
Reactome:R-HSA-390593
ATP Hydrolysis By Myosin
Reactome:R-HSA-390595
Calcium Binds Troponin-C
Reactome:R-HSA-390597
Release Of ADP From Myosin
Reactome:R-HSA-390598
Myosin Binds ATP
Reactome:R-HSA-445699
ATP Hydrolysis By Myosin
Reactome:R-HSA-445700
Myosin Binds ATP
Reactome:R-HSA-445704
Calcium Binds Caldesmon
Reactome:R-HSA-445705
Release Of ADP From Myosin

📚 Additional Documentation

Notes

(TPM1-notes.md)

TPM1 (Tropomyosin 1) Notes - ISOFORMS Project

Key Isoform Biology

TPM1 has 10 named isoforms with tissue-specific expression patterns.

Tissue-Specific Isoforms

Isoform UniProt ID Synonym Tissue Key Feature
Isoform 1 P09493-1 TPM1alpha, Skeletal Skeletal muscle Adult striated muscle
Isoform 2 P09493-2 Smooth muscle Smooth muscle Vascular, visceral
Isoform 3 P09493-3 TM3, Fibroblast Non-muscle cells Cytoskeletal function
Isoform 6 P09493-6 TPM1kappa Cardiac Cardiac-specific

Functional Distinctions

Striated muscle isoforms (1, 6):
- Regulate actin-myosin interaction in sarcomeres
- Essential for muscle contraction
- Mutations cause cardiomyopathy

Smooth muscle isoform (2):
- Different N-terminal sequence
- Expressed in blood vessels, uterus, GI tract
- Regulates smooth muscle contraction

Non-muscle isoforms (3, etc.):
- Cytoskeletal organization
- Cell motility
- Different actin binding properties

Disease Associations

Cardiomyopathy mutations:
- CMH3: Familial hypertrophic cardiomyopathy
- CMD1Y: Dilated cardiomyopathy
- Mutations affect sarcomere function

UniProt tissue specificity:

"Isoform 1 is expressed in adult and fetal skeletal muscle and cardiac tissues, with higher expression levels in the cardiac tissues. Isoform 10 is expressed in adult and fetal cardiac tissues, but not in skeletal muscle."

Expected Annotation Issues

  1. "Muscle contraction" - true for muscle isoforms, not cytoskeletal
  2. "Sarcomere organization" - only striated muscle isoforms
  3. "Cytoskeleton organization" - primarily non-muscle isoforms
  4. "Cardiac muscle function" - isoforms 1, 6, 10 specifically

GOA Annotation Count: 55

📄 View Raw YAML

id: P09493
gene_symbol: TPM1
product_type: PROTEIN
status: INITIALIZED
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: 'TPM1 (Tropomyosin 1) is a coiled-coil actin-binding protein with 10
  tissue-specific isoforms. ISOFORM BIOLOGY: (1) Isoform 1 (TPM1alpha, P09493-1) is
  expressed in SKELETAL MUSCLE; (2) Isoform 2 is SMOOTH MUSCLE-specific; (3) Isoform
  3 (TM3) is the FIBROBLAST/cytoskeletal form; (4) Isoform 6 (TPM1kappa) is CARDIAC-specific.
  UniProt states "Isoform 1 is expressed in adult and fetal skeletal muscle and cardiac
  tissues. Isoform 10 is expressed in adult and fetal cardiac tissues, but not in
  skeletal muscle." Muscle isoforms regulate actin-myosin interaction in sarcomeres;
  cytoskeletal isoforms organize non-muscle actin. DISEASE: Mutations cause cardiomyopathy
  (CMH3, CMD1Y) affecting sarcomere function. Annotations for "muscle contraction"
  and "sarcomere" apply primarily to muscle isoforms, while "cytoskeleton organization"
  applies more to non-muscle isoforms.'
existing_annotations:
  - term:
      id: GO:0051015
      label: actin filament binding
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: Core function of all TPM1 isoforms. Tropomyosin binds along the 
        length of actin filaments in both muscle and non-muscle cells. UniProt 
        states that TPM1 binds to actin filaments. This function is conserved 
        across all isoforms - muscle isoforms bind thin filament actin while 
        cytoskeletal isoforms bind stress fiber actin.
      action: ACCEPT
      reason: Actin filament binding is the fundamental molecular function of 
        all tropomyosins. IBA annotation is appropriate as this function is 
        phylogenetically conserved. Supported by functional studies showing TPM1
        binds actin filaments in both muscle and non-muscle contexts 
        [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
        - reference_id: PMID:8205619
          supporting_text: alpha-tropomyosin and cardiac troponin T as well as 
            beta myosin heavy chain mutations cause the same phenotype, we 
            conclude that FHC is a disease of the sarcomere
  - term:
      id: GO:0007015
      label: actin filament organization
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: TPM1 plays a role in actin filament organization in both muscle 
        and non-muscle cells. In muscle, it organizes thin filaments; in 
        non-muscle cells, it contributes to stress fiber formation and 
        cytoskeletal organization [PMID:12686598].
      action: ACCEPT
      reason: Actin filament organization is a core function of tropomyosins 
        across all isoforms. Muscle isoforms organize thin filaments in 
        sarcomeres; cytoskeletal isoforms stabilize stress fibers in non-muscle 
        cells. IBA annotation is appropriate.
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: phosphorylation of tropomyosin-1 downstream of ERK by
            contributing to formation of actin filaments increases cellular 
            contractility and promotes the formation of focal adhesions
        - reference_id: PMID:15897890
          supporting_text: TGF-beta induction of stress fibers in epithelial 
            cells requires high molecular weight tropomyosins encoded by TPM1 
            and TPM2 genes
  - term:
      id: GO:0005884
      label: actin filament
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: TPM1 localizes to actin filaments in both muscle and non-muscle 
        cells. This cellular component annotation reflects the physical location
        of tropomyosin bound along actin filaments.
      action: ACCEPT
      reason: Tropomyosin is an integral component of actin filaments. In muscle
        cells it forms the thin filament regulatory complex; in non-muscle cells
        it associates with stress fibers and other actin structures. IBA 
        annotation is appropriate.
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
  - term:
      id: GO:0060048
      label: cardiac muscle contraction
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: 'ISOFORM-SPECIFIC: Cardiac muscle contraction is a function of the
        striated muscle isoforms (Isoform 1/TPM1alpha and Isoform 6/TPM1kappa). UniProt
        states Isoform 1 is expressed in cardiac tissues and Isoform 6 is cardiac-specific.
        Mutations cause cardiomyopathy (CMH3, CMD1Y) [PMID:8205619, PMID:11273725].'
      action: ACCEPT
      reason: This is a core function for cardiac isoforms. TPM1 plays a central
        role in calcium-dependent regulation of cardiac muscle contraction via 
        the troponin complex. Mutations affecting this function cause 
        hypertrophic and dilated cardiomyopathy, demonstrating its importance 
        [PMID:8205619]. IBA annotation is appropriate as this function is 
        conserved in striated muscle isoforms.
      supported_by:
        - reference_id: PMID:8205619
          supporting_text: We demonstrate that missense mutations (Asp175Asn; 
            Glu180Gly) in the alpha-tropomyosin gene cause familial hypertrophic
            cardiomyopathy (FHC)
        - reference_id: PMID:11136687
          supporting_text: HCM was linked to the TPM1 gene... The mutation 
            caused a 40% to 50% increase in calcium affinity in regulated thin 
            filament-myosin subfragment-1 (S1) MgATPase assays
  - term:
      id: GO:0003779
      label: actin binding
    evidence_type: IEA
    original_reference_id: GO_REF:0000043
    review:
      summary: Actin binding is the fundamental molecular function of all 
        tropomyosins. This IEA annotation based on UniProt keyword mapping is 
        correct but less specific than GO:0051015 (actin filament binding) which
        is already annotated via IBA.
      action: ACCEPT
      reason: While this is a broader parent term of actin filament binding, it 
        is still correct. IEA annotations at a broader level are acceptable 
        alongside more specific experimental annotations. No action needed as 
        the more specific IBA annotation (GO:0051015) captures the precise 
        function.
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
  - term:
      id: GO:0005856
      label: cytoskeleton
    evidence_type: IEA
    original_reference_id: GO_REF:0000044
    review:
      summary: TPM1 is a cytoskeletal protein. UniProt subcellular location 
        indicates "Cytoplasm, cytoskeleton" and notes it "Associates with 
        F-actin stress fibers." This is a broad cellular component annotation 
        appropriate for all isoforms.
      action: ACCEPT
      reason: This is a valid broad localization term. All TPM1 isoforms are 
        components of the cytoskeleton, whether in sarcomeres (muscle isoforms) 
        or stress fibers (non-muscle isoforms). IEA based on UniProt subcellular
        location is appropriate.
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
  - term:
      id: GO:0005862
      label: muscle thin filament tropomyosin
    evidence_type: IEA
    original_reference_id: GO_REF:0000117
    review:
      summary: 'ISOFORM-SPECIFIC: This cellular component term is specifically for
        muscle isoforms (Isoform 1/skeletal, Isoform 2/smooth, Isoform 6/cardiac).
        The muscle thin filament tropomyosin complex contains tropomyosin bound to
        actin filaments in sarcomeres. Non-muscle isoforms (e.g., Isoform 3/fibroblast)
        do not form this specific complex.'
      action: ACCEPT
      reason: This is a core localization for muscle isoforms of TPM1. The 
        annotation is correct for the muscle-expressed isoforms that are 
        integral to the thin filament regulatory complex in sarcomeres 
        [PMID:8205619].
      supported_by:
        - reference_id: PMID:8205619
          supporting_text: FHC is a disease of the sarcomere
        - reference_id: PMID:11136687
          supporting_text: regulated thin filament-myosin subfragment-1 (S1) 
            MgATPase assays
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:16189514
    review:
      summary: High-throughput Y2H interactome study. The term "protein binding"
        is uninformative and does not indicate specific binding partners or 
        functional context. TPM1 binds actin, troponins, and other 
        muscle/cytoskeletal proteins, but this generic term does not capture 
        those specific interactions.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" (GO:0005515) is an uninformative annotation that
        does not convey the specific molecular interactions of TPM1 (e.g., actin binding,
        troponin complex binding). High-throughput interactome studies often generate
        these generic annotations. More specific MF terms are preferred [PMID:16189514].'
      supported_by:
        - reference_id: PMID:16189514
          supporting_text: Using a stringent, high-throughput yeast two-hybrid 
            system, we tested pairwise interactions among the products of 
            approximately 8,100 currently available Gateway-cloned open reading 
            frames and detected approximately 2,800 interactions
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:21516116
    review:
      summary: High-throughput Stitch-seq Y2H interactome study. The generic 
        term "protein binding" is uninformative for this well-characterized 
        actin-binding protein.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" (GO:0005515) from high-throughput interactome studies
        is too generic. TPM1 has specific, well-characterized binding partners (actin,
        troponins, LMOD2, TMOD1) that are more informative [PMID:21516116].'
      supported_by:
        - reference_id: PMID:21516116
          supporting_text: We describe a massively parallel interactome-mapping 
            pipeline, Stitch-seq, that combines PCR stitching with 
            next-generation sequencing and used it to generate a new human 
            interactome dataset
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:25416956
    review:
      summary: Large-scale proteome-scale human interactome map study. Generic 
        "protein binding" term is uninformative for TPM1 which has 
        well-characterized specific interactions.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" (GO:0005515) from systematic interactome mapping
        is too generic. TPM1 has specific, functionally important binding partners
        that should be annotated instead [PMID:25416956].'
      supported_by:
        - reference_id: PMID:25416956
          supporting_text: Here, we describe a systematic map of ?14,000 
            high-quality human binary protein-protein interactions
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:26871637
    review:
      summary: Study on alternative splicing and protein interaction 
        capabilities. Notably relevant for TPM1 which has 10 isoforms with 
        different interaction profiles. However "protein binding" remains 
        uninformative.
      action: MARK_AS_OVER_ANNOTATED
      reason: While this study is highly relevant to TPM1 isoform biology, 
        showing that alternative isoforms exhibit different interaction 
        profiles, the generic "protein binding" term does not capture the 
        specific binding partners or isoform-specific interactions 
        [PMID:26871637].
      supported_by:
        - reference_id: PMID:26871637
          supporting_text: The majority of isoform pairs share less than 50% of 
            their interactions. In the global context of interactome network 
            maps, alternative isoforms tend to behave like distinct proteins 
            rather than minor variants of each other
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:30021884
    review:
      summary: Crosslinking mass spectrometry study of histone interactions in 
        nuclei. TPM1 is a cytoplasmic/cytoskeletal protein; its detection here 
        may be incidental. Generic "protein binding" term is uninformative.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" from crosslinking MS study of nuclear proteins is
        not informative for TPM1, which is primarily a cytoskeletal protein. The generic
        term provides no functional insight [PMID:30021884].'
      supported_by:
        - reference_id: PMID:30021884
          supporting_text: Here we use crosslinking mass spectrometry (XL-MS) to
            chart the protein-protein interactions in intact human nuclei
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:33961781
    review:
      summary: BioPlex 3.0 dual proteome-scale network study in 293T and HCT116 
        cells. While this reveals cell-specific interactome remodeling relevant 
        to TPM1 isoforms, the generic "protein binding" term is uninformative.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" from large-scale AP-MS interactome study does not
        provide specific information about TPM1''s functional binding partners. More
        specific terms for actin binding, troponin binding etc. are preferred [PMID:33961781].'
      supported_by:
        - reference_id: PMID:33961781
          supporting_text: Thousands of interactions assemble proteins into 
            modules that impart spatial and functional organization to the 
            cellular proteome
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:40205054
    review:
      summary: Multimodal cell maps study integrating multiple data types for 
        structural and functional genomics. Generic "protein binding" term is 
        uninformative.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" from multimodal cell mapping study does not convey
        specific information about TPM1''s well-characterized binding partners [PMID:40205054].'
      supported_by:
        - reference_id: PMID:40205054
          supporting_text: Multimodal cell maps as a foundation for structural 
            and functional genomics
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:25910212
    isoform: P09493-10
    review:
      summary: ISOFORM-SPECIFIC ANNOTATION (P09493-10). Study on macromolecular 
        interaction perturbations in genetic disorders. While highly relevant to
        understanding how TPM1 mutations affect interactions, "protein binding" 
        is uninformative.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" from edgetic mutation studies is too generic. This
        study shows disease mutations can perturb specific interactions, but the annotation
        lacks specificity about which interactions [PMID:25910212].'
      supported_by:
        - reference_id: PMID:25910212
          supporting_text: While common variants from healthy individuals rarely
            affect interactions, two-thirds of disease-associated alleles 
            perturb protein-protein interactions, with half corresponding to 
            "edgetic" alleles affecting only a subset of interactions while 
            leaving most other interactions unperturbed
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:32296183
    isoform: P09493-10
    review:
      summary: ISOFORM-SPECIFIC ANNOTATION (P09493-10). HuRI reference human 
        binary protein interactome map. While highly valuable for mapping 
        interactions, the generic "protein binding" term is uninformative for 
        TPM1.
      action: MARK_AS_OVER_ANNOTATED
      reason: '"Protein binding" from the comprehensive HuRI interactome map does
        not convey specific binding partners. TPM1 has well-characterized interactions
        with actin, troponins, and other thin filament proteins that are more informative
        [PMID:32296183].'
      supported_by:
        - reference_id: PMID:32296183
          supporting_text: Here we present a human 'all-by-all' reference 
            interactome map of human binary protein interactions, or 'HuRI'
  - term:
      id: GO:0042802
      label: identical protein binding
    evidence_type: ISS
    original_reference_id: GO_REF:0000024
    review:
      summary: Tropomyosins form coiled-coil dimers (homo- or heterodimers) as 
        their functional unit. UniProt indicates TPM1 forms dimers with itself 
        or other tropomyosin isoforms. This ISS annotation from sequence 
        similarity is consistent with the coiled-coil structure of tropomyosins.
      action: ACCEPT
      reason: TPM1 forms parallel coiled-coil dimers that bind along actin 
        filaments. This is a fundamental structural property of all 
        tropomyosins. Self-association (homodimerization) is documented in 
        UniProt. ISS annotation based on sequence similarity to characterized 
        orthologs is appropriate.
  - term:
      id: GO:0042803
      label: protein homodimerization activity
    evidence_type: ISS
    original_reference_id: GO_REF:0000024
    review:
      summary: Tropomyosins function as coiled-coil dimers. TPM1 homodimerizes 
        to form the functional unit that binds along actin filaments. This is a 
        core structural property of tropomyosins.
      action: ACCEPT
      reason: Homodimerization is fundamental to tropomyosin function. Two TPM1 
        chains form a parallel coiled-coil dimer that spans seven actin 
        subunits. ISS annotation based on sequence similarity is appropriate for
        this conserved structural property.
  - term:
      id: GO:0046982
      label: protein heterodimerization activity
    evidence_type: ISS
    original_reference_id: GO_REF:0000024
    review:
      summary: TPM1 can form heterodimers with other tropomyosin isoforms (e.g.,
        TPM2, TPM3). UniProt indicates it interacts with self or TPM2. 
        Heterodimer formation provides functional diversity in different tissue 
        contexts.
      action: ACCEPT
      reason: Heterodimerization with other tropomyosin isoforms is a documented
        property that provides functional diversity. TPM1 can form dimers with 
        TPM2 and potentially other isoforms. ISS annotation based on sequence 
        similarity is appropriate.
  - term:
      id: GO:0051015
      label: actin filament binding
    evidence_type: ISS
    original_reference_id: GO_REF:0000024
    review:
      summary: Duplicate of the IBA annotation for actin filament binding. This 
        ISS annotation provides additional evidence for this core function from 
        sequence similarity.
      action: ACCEPT
      reason: Actin filament binding is the fundamental molecular function of 
        TPM1 across all isoforms. This ISS annotation supplements the IBA 
        annotation and is consistent with the conserved function of 
        tropomyosins.
  - term:
      id: GO:0008360
      label: regulation of cell shape
    evidence_type: IMP
    original_reference_id: PMID:21817107
    review:
      summary: 'ISOFORM-SPECIFIC: This annotation relates to the cytoskeletal (non-muscle)
        function of TPM1 isoforms. The study shows TPM1 affects vascular smooth muscle
        cell morphology via cytoskeletal remodeling [PMID:21817107].'
      action: KEEP_AS_NON_CORE
      reason: Regulation of cell shape is a function of cytoskeletal TPM1 
        isoforms in non-muscle cells. While important, it is not the core 
        function of the striated muscle isoforms. This is a valid annotation for
        cytoskeletal isoforms [PMID:21817107].
      supported_by:
        - reference_id: PMID:21817107
          supporting_text: cell proliferation and migration were significantly 
            decreased by
  - term:
      id: GO:1904706
      label: negative regulation of vascular associated smooth muscle cell 
        proliferation
    evidence_type: IMP
    original_reference_id: PMID:21817107
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 overexpression inhibits vascular smooth muscle
        cell (VSMC) proliferation. This relates to the cytoskeletal function of TPM1
        in regulating cell behavior [PMID:21817107].'
      action: KEEP_AS_NON_CORE
      reason: This is a valid functional annotation for cytoskeletal TPM1 
        isoforms in smooth muscle cells. While biologically relevant, it 
        represents a peripheral function rather than the core sarcomeric 
        function of TPM1 [PMID:21817107].
      supported_by:
        - reference_id: PMID:21817107
          supporting_text: cell proliferation and migration were significantly 
            decreased by
  - term:
      id: GO:1904753
      label: negative regulation of vascular associated smooth muscle cell 
        migration
    evidence_type: IMP
    original_reference_id: PMID:21817107
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 overexpression inhibits vascular smooth muscle
        cell (VSMC) migration. This relates to the cytoskeletal function of TPM1 in
        regulating cell motility [PMID:21817107].'
      action: KEEP_AS_NON_CORE
      reason: This is a valid functional annotation for cytoskeletal TPM1 
        isoforms in smooth muscle cells. While biologically relevant, it 
        represents a peripheral function rather than the core sarcomeric 
        function of TPM1 [PMID:21817107].
      supported_by:
        - reference_id: PMID:21817107
          supporting_text: cell proliferation and migration were significantly 
            decreased by
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-390593
    review:
      summary: Reactome pathway annotation for muscle contraction. TPM1 is a 
        cytosolic/ cytoskeletal protein that associates with actin filaments. 
        Cytosol localization is valid for soluble tropomyosin before assembly.
      action: ACCEPT
      reason: Cytosol is an appropriate cellular component for TPM1. Prior to 
        incorporation into actin filaments, tropomyosin exists in the cytosol. 
        Reactome pathway annotations for muscle contraction support this 
        localization.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-390595
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization in
        muscle contraction pathway.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome muscle 
        contraction pathway. Cytosol localization is appropriate for soluble 
        tropomyosin.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-390597
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome pathway. Cytosol
        localization is appropriate for soluble tropomyosin.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-390598
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome pathway. Cytosol
        localization is appropriate for soluble tropomyosin.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-445699
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome pathway. Cytosol
        localization is appropriate for soluble tropomyosin.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-445700
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome pathway. Cytosol
        localization is appropriate for soluble tropomyosin.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-445704
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome pathway. Cytosol
        localization is appropriate for soluble tropomyosin.
  - term:
      id: GO:0005829
      label: cytosol
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-445705
    review:
      summary: Duplicate Reactome pathway annotation for cytosol localization.
      action: ACCEPT
      reason: Valid cellular component annotation from Reactome pathway. Cytosol
        localization is appropriate for soluble tropomyosin.
  - term:
      id: GO:0008092
      label: cytoskeletal protein binding
    evidence_type: IPI
    original_reference_id: PMID:17987659
    review:
      summary: TPM1 binds cytoskeletal proteins including nebulette. The study 
        identified tropomyosin-1 as a binding partner of nebulette in a yeast 
        two-hybrid screen [PMID:17987659].
      action: ACCEPT
      reason: Cytoskeletal protein binding accurately describes TPM1's 
        interactions with actin filaments and associated regulatory proteins. 
        This is a valid molecular function annotation that is more specific than
        "protein binding".
      supported_by:
        - reference_id: PMID:17987659
          supporting_text: Nebulette interacts with filamin C.
  - term:
      id: GO:0045214
      label: sarcomere organization
    evidence_type: IMP
    original_reference_id: PMID:11273725
    review:
      summary: 'ISOFORM-SPECIFIC: Sarcomere organization is a function of muscle isoforms.
        TPM1 mutations cause disorganized sarcomere structure in cardiomyopathy [PMID:11273725].'
      action: ACCEPT
      reason: Sarcomere organization is a core function of striated muscle TPM1 
        isoforms. Mutations affecting this function cause hypertrophic and 
        dilated cardiomyopathy. This is a well-supported experimental annotation
        [PMID:11273725].
      supported_by:
        - reference_id: PMID:11273725
          supporting_text: Proteins in cardiac myocytes assemble into 
            contractile units known as sarcomeres
  - term:
      id: GO:0001725
      label: stress fiber
    evidence_type: IDA
    original_reference_id: PMID:12686598
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 localizes to stress fibers in non-muscle cells.
        The study shows TPM1 colocalizes with actin stress fibers upon stimulation
        [PMID:12686598].'
      action: ACCEPT
      reason: Stress fiber localization is a valid cellular component annotation
        for cytoskeletal TPM1 isoforms (e.g., Isoform 3/TM3). IDA evidence from 
        direct observation of colocalization with stress fibers [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
  - term:
      id: GO:0003065
      label: positive regulation of heart rate by epinephrine
    evidence_type: ISS
    original_reference_id: PMID:17556658
    review:
      summary: 'ISOFORM-SPECIFIC: This relates to cardiac isoforms (TPM1alpha, TPM1kappa)
        and their role in beta-adrenergic signaling in the heart. Tropomyosin phosphorylation
        modulates cardiac contractility.'
      action: KEEP_AS_NON_CORE
      reason: While TPM1 is involved in cardiac muscle contraction, the specific
        role in epinephrine-mediated heart rate regulation is indirect via 
        modulation of thin filament Ca2+ sensitivity. This is a secondary 
        function rather than a core molecular function.
      supported_by:
        - reference_id: PMID:17556658
          supporting_text: 2007 Jun 7. Dilated cardiomyopathy mutant tropomyosin
            mice develop cardiac dysfunction with significantly decreased 
            fractional shortening and myofilament calcium sensitivity.
  - term:
      id: GO:0003779
      label: actin binding
    evidence_type: TAS
    original_reference_id: PMID:12686598
    review:
      summary: Core function of TPM1. Actin binding is fundamental to all TPM1 
        isoforms. This TAS annotation based on literature review is consistent 
        with the well-established role of tropomyosin [PMID:12686598].
      action: ACCEPT
      reason: Actin binding is the fundamental molecular function of 
        tropomyosin. This annotation supplements the more specific "actin 
        filament binding" term already annotated via IBA [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
  - term:
      id: GO:0005200
      label: structural constituent of cytoskeleton
    evidence_type: TAS
    original_reference_id: PMID:12686598
    review:
      summary: TPM1 is a structural component of the actin cytoskeleton in both 
        muscle and non-muscle cells. In muscle cells it forms thin filaments; in
        non-muscle cells it stabilizes stress fibers [PMID:12686598].
      action: ACCEPT
      reason: Structural constituent of cytoskeleton is an accurate molecular 
        function for TPM1. Tropomyosin provides structural stability to actin 
        filaments and is integral to cytoskeletal architecture [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: phosphorylation of tropomyosin-1 downstream of ERK by
            contributing to formation of actin filaments increases cellular 
            contractility and promotes the formation of focal adhesions
  - term:
      id: GO:0007010
      label: cytoskeleton organization
    evidence_type: TAS
    original_reference_id: PMID:12686598
    review:
      summary: TPM1 contributes to cytoskeleton organization in both muscle and 
        non-muscle cells. This is closely related to actin filament organization
        [PMID:12686598].
      action: ACCEPT
      reason: Cytoskeleton organization is a core function of TPM1 across all 
        isoforms. In muscle, it organizes sarcomere thin filaments; in 
        non-muscle cells, it contributes to stress fiber organization 
        [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: phosphorylation of tropomyosin-1 downstream of ERK by
            contributing to formation of actin filaments increases cellular 
            contractility and promotes the formation of focal adhesions
  - term:
      id: GO:0030049
      label: muscle filament sliding
    evidence_type: ISS
    original_reference_id: PMID:11136687
    review:
      summary: 'ISOFORM-SPECIFIC: Muscle filament sliding is a function of striated
        muscle isoforms. TPM1 regulates the interaction between thin and thick filaments
        during muscle contraction [PMID:11136687].'
      action: ACCEPT
      reason: Muscle filament sliding is a core function of muscle TPM1 
        isoforms. Tropomyosin regulates the actin-myosin interaction that drives
        filament sliding during contraction. Mutations affecting this cause 
        cardiomyopathy [PMID:11136687].
      supported_by:
        - reference_id: PMID:11136687
          supporting_text: The mutation caused a 40% to 50% increase in calcium 
            affinity in regulated thin filament-myosin subfragment-1 (S1) 
            MgATPase assays
  - term:
      id: GO:0030336
      label: negative regulation of cell migration
    evidence_type: ISS
    original_reference_id: PMID:15897890
    review:
      summary: 'ISOFORM-SPECIFIC: Cytoskeletal TPM1 isoforms regulate cell migration.
        High molecular weight tropomyosins stabilize stress fibers and inhibit cell
        motility [PMID:15897890].'
      action: KEEP_AS_NON_CORE
      reason: Regulation of cell migration is a function of cytoskeletal TPM1 
        isoforms in non-muscle cells. While valid, this is a peripheral function
        related to the core actin-binding activity [PMID:15897890].
      supported_by:
        - reference_id: PMID:15897890
          supporting_text: TGF-beta induction of stress fibers in epithelial 
            cells requires high molecular weight tropomyosins encoded by TPM1 
            and TPM2 genes
  - term:
      id: GO:0031529
      label: ruffle organization
    evidence_type: ISS
    original_reference_id: PMID:15897890
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 affects membrane ruffle organization in non-muscle
        cells. This relates to cytoskeletal actin dynamics [PMID:15897890].'
      action: KEEP_AS_NON_CORE
      reason: Ruffle organization is a function of cytoskeletal TPM1 isoforms in
        non-muscle cells. This is a peripheral function related to the core 
        actin-organizing activity [PMID:15897890].
      supported_by:
        - reference_id: PMID:15897890
          supporting_text: TGF-beta induction of stress fibers in epithelial 
            cells requires high molecular weight tropomyosins encoded by TPM1 
            and TPM2 genes
  - term:
      id: GO:0032059
      label: bleb
    evidence_type: IMP
    original_reference_id: PMID:12686598
    review:
      summary: TPM1 localizes to membrane blebs in response to oxidative stress.
        This relates to cytoskeletal reorganization during stress responses 
        [PMID:12686598].
      action: KEEP_AS_NON_CORE
      reason: Bleb localization is a peripheral cellular component annotation 
        related to stress responses rather than core TPM1 function 
        [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: presence of H(2)O(2) resulted in a quick and intense 
            membrane blebbing
  - term:
      id: GO:0032587
      label: ruffle membrane
    evidence_type: IDA
    original_reference_id: PMID:12686598
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 localizes to ruffle membranes in non-muscle
        cells. This relates to cytoskeletal actin dynamics at the cell periphery [PMID:12686598].'
      action: KEEP_AS_NON_CORE
      reason: Ruffle membrane localization is a cellular component for 
        cytoskeletal TPM1 isoforms in non-muscle cells. This is a peripheral 
        localization related to actin dynamics [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: tropomyosin-1 was found diffuse in the cells, whereas
            it quickly colocalized with actin and stress fibers upon stimulation
  - term:
      id: GO:0034614
      label: cellular response to reactive oxygen species
    evidence_type: IEP
    original_reference_id: PMID:12686598
    review:
      summary: TPM1 is phosphorylated in response to oxidative stress via ERK 
        signaling. This leads to cytoskeletal remodeling and affects membrane 
        dynamics [PMID:12686598].
      action: KEEP_AS_NON_CORE
      reason: Response to ROS is a peripheral function related to stress-induced
        cytoskeletal remodeling. TPM1 phosphorylation downstream of ERK 
        modulates stress fiber formation during oxidative stress 
        [PMID:12686598].
      supported_by:
        - reference_id: PMID:12686598
          supporting_text: phosphorylation of tropomyosin-1 downstream of ERK by
            contributing to formation of actin filaments increases cellular 
            contractility and promotes the formation of focal adhesions
  - term:
      id: GO:0042060
      label: wound healing
    evidence_type: ISS
    original_reference_id: PMID:17721995
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 is involved in wound healing through its role
        in cytoskeletal remodeling and cell migration during tissue repair [PMID:17721995].'
      action: KEEP_AS_NON_CORE
      reason: Wound healing is a peripheral function of cytoskeletal TPM1 
        isoforms related to cell migration and tissue remodeling. While 
        biologically relevant, this is not a core molecular function 
        [PMID:17721995].
      supported_by:
        - reference_id: PMID:17721995
          supporting_text: HMW-tropomyosins are important for TGF-beta-mediated 
            control of cell
  - term:
      id: GO:0045785
      label: positive regulation of cell adhesion
    evidence_type: ISS
    original_reference_id: PMID:17721995
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 promotes cell adhesion by enhancing actin stress
        fibers and focal adhesions in non-muscle cells [PMID:17721995].'
      action: KEEP_AS_NON_CORE
      reason: Regulation of cell adhesion is a peripheral function of 
        cytoskeletal TPM1 isoforms related to stress fiber stabilization 
        [PMID:17721995].
      supported_by:
        - reference_id: PMID:17721995
          supporting_text: Tropomyosin increased cell adhesion to matrix by 
            enhancing actin fibers and focal adhesions
  - term:
      id: GO:0051496
      label: positive regulation of stress fiber assembly
    evidence_type: ISS
    original_reference_id: PMID:15897890
    review:
      summary: 'ISOFORM-SPECIFIC: TPM1 (HMW tropomyosins) are required for TGF-beta-induced
        stress fiber assembly in epithelial cells [PMID:15897890].'
      action: ACCEPT
      reason: Positive regulation of stress fiber assembly is a well-documented 
        function of cytoskeletal TPM1 isoforms. HMW tropomyosins stabilize and 
        promote stress fiber formation [PMID:15897890].
      supported_by:
        - reference_id: PMID:15897890
          supporting_text: TGF-beta induction of stress fibers in epithelial 
            cells requires high molecular weight tropomyosins encoded by TPM1 
            and TPM2 genes
  - term:
      id: GO:0055010
      label: ventricular cardiac muscle tissue morphogenesis
    evidence_type: IMP
    original_reference_id: PMID:11136687
    review:
      summary: 'ISOFORM-SPECIFIC: Cardiac TPM1 isoforms are essential for ventricular
        morphogenesis. Mutations cause hypertrophic cardiomyopathy with ventricular
        hypertrophy [PMID:11136687].'
      action: KEEP_AS_NON_CORE
      reason: Ventricular morphogenesis is a developmental process that TPM1 
        mutations affect. While important, this is a downstream consequence of 
        TPM1's role in cardiac muscle function rather than a core molecular 
        function [PMID:11136687].
      supported_by:
        - reference_id: PMID:11136687
          supporting_text: The mutation caused a 40% to 50% increase in calcium 
            affinity in regulated thin filament-myosin subfragment-1 (S1) 
            MgATPase assays
  - term:
      id: GO:0060048
      label: cardiac muscle contraction
    evidence_type: IMP
    original_reference_id: PMID:11136687
    review:
      summary: 'ISOFORM-SPECIFIC: This IMP annotation with experimental evidence complements
        the IBA annotation for cardiac muscle contraction. TPM1 mutations affect Ca2+
        sensitivity and muscle contraction [PMID:11136687].'
      action: ACCEPT
      reason: Cardiac muscle contraction is a core function of cardiac TPM1 
        isoforms. This experimental annotation provides direct evidence that 
        TPM1 mutations affect cardiac contractile function [PMID:11136687].
      supported_by:
        - reference_id: PMID:11136687
          supporting_text: The mutation caused a 40% to 50% increase in calcium 
            affinity in regulated thin filament-myosin subfragment-1 (S1) 
            MgATPase assays
  - term:
      id: GO:0030017
      label: sarcomere
    evidence_type: TAS
    original_reference_id: PMID:16754800
    review:
      summary: 'ISOFORM-SPECIFIC: Sarcomere localization is specific to striated muscle
        TPM1 isoforms. TPM1 is an integral component of thin filaments in sarcomeres.'
      action: ACCEPT
      reason: Sarcomere is a core cellular component for muscle TPM1 isoforms. 
        Tropomyosin is an integral part of the thin filament in sarcomeric 
        structures. TAS annotation from literature supports this 
        well-established localization.
      supported_by:
        - reference_id: PMID:16754800
          supporting_text: 'Single-gene mutations and increased left ventricular wall
            thickness in the community: the Framingham Heart Study.'
  - term:
      id: GO:0005856
      label: cytoskeleton
    evidence_type: TAS
    original_reference_id: PMID:16130169
    review:
      summary: TPM1 is a cytoskeletal protein identified in proteomic studies of
        endothelial cells. This annotation complements the IEA cytoskeleton 
        annotation.
      action: ACCEPT
      reason: Cytoskeleton is a valid cellular component for TPM1. All isoforms 
        are components of the cytoskeleton, whether in sarcomeres or stress 
        fibers. TAS annotation is appropriate.
      supported_by:
        - reference_id: PMID:16130169
          supporting_text: Proteomics of human umbilical vein endothelial cells 
            applied to etoposide-induced apoptosis.
  - term:
      id: GO:0005862
      label: muscle thin filament tropomyosin
    evidence_type: TAS
    original_reference_id: PMID:8205619
    review:
      summary: 'ISOFORM-SPECIFIC: This TAS annotation complements the IEA annotation
        for muscle thin filament tropomyosin. TPM1 mutations in this complex cause
        familial hypertrophic cardiomyopathy [PMID:8205619].'
      action: ACCEPT
      reason: Muscle thin filament tropomyosin is a core cellular component for 
        muscle TPM1 isoforms. The cited study demonstrates TPM1's role in the 
        thin filament complex and disease consequences of mutations 
        [PMID:8205619].
      supported_by:
        - reference_id: PMID:8205619
          supporting_text: alpha-tropomyosin and cardiac troponin T as well as 
            beta myosin heavy chain mutations cause the same phenotype, we 
            conclude that FHC is a disease of the sarcomere
  - term:
      id: GO:0006937
      label: regulation of muscle contraction
    evidence_type: TAS
    original_reference_id: PMID:3336363
    review:
      summary: 'ISOFORM-SPECIFIC: Regulation of muscle contraction is a core function
        of muscle TPM1 isoforms. The study describes expression of alpha-tropomyosin
        in muscle and non-muscle tissues.'
      action: ACCEPT
      reason: Regulation of muscle contraction is a core biological process for 
        muscle TPM1 isoforms. Tropomyosin regulates actin-myosin interaction in 
        a Ca2+-dependent manner via the troponin complex. TAS annotation is 
        appropriate.
      supported_by:
        - reference_id: PMID:3336363
          supporting_text: 'Human hTM alpha gene: expression in muscle and nonmuscle
            tissue.'
  - term:
      id: GO:0008016
      label: regulation of heart contraction
    evidence_type: TAS
    original_reference_id: PMID:8205619
    review:
      summary: 'ISOFORM-SPECIFIC: Cardiac TPM1 isoforms regulate heart contraction.
        Mutations cause familial hypertrophic cardiomyopathy, demonstrating the essential
        role of TPM1 in cardiac function [PMID:8205619].'
      action: ACCEPT
      reason: Regulation of heart contraction is a core function of cardiac TPM1
        isoforms. Mutations affecting this function cause cardiomyopathy 
        [PMID:8205619].
      supported_by:
        - reference_id: PMID:8205619
          supporting_text: We demonstrate that missense mutations (Asp175Asn; 
            Glu180Gly) in the alpha-tropomyosin gene cause familial hypertrophic
            cardiomyopathy (FHC)
  - term:
      id: GO:0008307
      label: structural constituent of muscle
    evidence_type: TAS
    original_reference_id: PMID:8205619
    review:
      summary: 'ISOFORM-SPECIFIC: Muscle TPM1 isoforms are structural constituents
        of muscle thin filaments in sarcomeres [PMID:8205619].'
      action: ACCEPT
      reason: Structural constituent of muscle is a core molecular function for 
        muscle TPM1 isoforms. TPM1 is an integral structural component of thin 
        filaments in sarcomeres [PMID:8205619].
      supported_by:
        - reference_id: PMID:8205619
          supporting_text: alpha-tropomyosin and cardiac troponin T as well as 
            beta myosin heavy chain mutations cause the same phenotype, we 
            conclude that FHC is a disease of the sarcomere
core_functions:
  - molecular_function:
      id: GO:0051015
      label: actin filament binding
    description: Actin filament binding is the fundamental molecular function of
      all TPM1 isoforms. Tropomyosin dimers bind along the length of actin 
      filaments in both muscle (thin filaments) and non-muscle (stress fibers) 
      cells, stabilizing actin filaments and regulating their interactions with 
      other proteins.
    directly_involved_in:
      - id: GO:0007015
        label: actin filament organization
    locations:
      - id: GO:0005884
        label: actin filament
  - molecular_function:
      id: GO:0051015
      label: actin filament binding
    description: 'ISOFORM-SPECIFIC (Cardiac isoforms): Cardiac muscle contraction
      is a core function of striated muscle isoforms (TPM1alpha, TPM1kappa). TPM1
      regulates calcium-dependent actin-myosin interaction via the troponin complex.
      Mutations cause cardiomyopathy (CMH3, CMD1Y).'
    directly_involved_in:
      - id: GO:0060048
        label: cardiac muscle contraction
      - id: GO:0006937
        label: regulation of muscle contraction
    locations:
      - id: GO:0030017
        label: sarcomere
    in_complex:
      id: GO:0005862
      label: muscle thin filament tropomyosin
  - molecular_function:
      id: GO:0051015
      label: actin filament binding
    description: 'ISOFORM-SPECIFIC (Cytoskeletal isoforms): Non-muscle TPM1 isoforms
      (e.g., TM3) bind actin filaments in stress fibers and contribute to cytoskeletal
      organization, cell shape regulation, and cell motility.'
    directly_involved_in:
      - id: GO:0007015
        label: actin filament organization
      - id: GO:0051496
        label: positive regulation of stress fiber assembly
    locations:
      - id: GO:0001725
        label: stress fiber
references:
  - id: GO_REF:0000024
    title: Manual transfer of experimentally-verified manual GO annotation data 
      to orthologs by curator judgment of sequence similarity
    findings: []
  - id: GO_REF:0000033
    title: Annotation inferences using phylogenetic trees
    findings: []
  - id: GO_REF:0000043
    title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword 
      mapping
    findings: []
  - id: GO_REF:0000044
    title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular 
      Location vocabulary mapping, accompanied by conservative changes to GO 
      terms applied by UniProt
    findings: []
  - id: GO_REF:0000117
    title: Electronic Gene Ontology annotations created by ARBA machine learning
      models
    findings: []
  - id: PMID:11136687
    title: Hypertrophic cardiomyopathy caused by a novel alpha-tropomyosin 
      mutation (V95A) is associated with mild cardiac phenotype, abnormal 
      calcium binding to troponin, abnormal myosin cycling, and poor prognosis.
    findings: []
  - id: PMID:11273725
    title: Mutations that alter the surface charge of alpha-tropomyosin are 
      associated with dilated cardiomyopathy.
    findings: []
  - id: PMID:12686598
    title: 'Extracellular signal-regulated kinase mediates phosphorylation of tropomyosin-1
      to promote cytoskeleton remodeling in response to oxidative stress: impact on
      membrane blebbing.'
    findings: []
  - id: PMID:15897890
    title: Silencing of the Tropomyosin-1 gene by DNA methylation alters tumor 
      suppressor function of TGF-beta.
    findings: []
  - id: PMID:16130169
    title: Proteomics of human umbilical vein endothelial cells applied to 
      etoposide-induced apoptosis.
    findings: []
  - id: PMID:16189514
    title: Towards a proteome-scale map of the human protein-protein interaction
      network.
    findings: []
  - id: PMID:16754800
    title: 'Single-gene mutations and increased left ventricular wall thickness in
      the community: the Framingham Heart Study.'
    findings: []
  - id: PMID:17556658
    title: Dilated cardiomyopathy mutant tropomyosin mice develop cardiac 
      dysfunction with significantly decreased fractional shortening and 
      myofilament calcium sensitivity.
    findings: []
  - id: PMID:17721995
    title: Role of high-molecular weight tropomyosins in TGF-beta-mediated 
      control of cell motility.
    findings: []
  - id: PMID:17987659
    title: Nebulette interacts with filamin C.
    findings: []
  - id: PMID:21516116
    title: Next-generation sequencing to generate interactome datasets.
    findings: []
  - id: PMID:21817107
    title: MicroRNA-21 regulates vascular smooth muscle cell function via 
      targeting tropomyosin 1 in arteriosclerosis obliterans of lower 
      extremities.
    findings: []
  - id: PMID:25416956
    title: A proteome-scale map of the human interactome network.
    findings: []
  - id: PMID:25910212
    title: Widespread macromolecular interaction perturbations in human genetic 
      disorders.
    findings: []
  - id: PMID:26871637
    title: Widespread Expansion of Protein Interaction Capabilities by 
      Alternative Splicing.
    findings: []
  - id: PMID:30021884
    title: Histone Interaction Landscapes Visualized by Crosslinking Mass 
      Spectrometry in Intact Cell Nuclei.
    findings: []
  - id: PMID:32296183
    title: A reference map of the human binary protein interactome.
    findings: []
  - id: PMID:3336363
    title: 'Human hTM alpha gene: expression in muscle and nonmuscle tissue.'
    findings: []
  - id: PMID:33961781
    title: Dual proteome-scale networks reveal cell-specific remodeling of the 
      human interactome.
    findings: []
  - id: PMID:40205054
    title: Multimodal cell maps as a foundation for structural and functional 
      genomics.
    findings: []
  - id: PMID:8205619
    title: 'Alpha-tropomyosin and cardiac troponin T mutations cause familial hypertrophic
      cardiomyopathy: a disease of the sarcomere.'
    findings: []
  - id: Reactome:R-HSA-390593
    title: ATP Hydrolysis By Myosin
    findings: []
  - id: Reactome:R-HSA-390595
    title: Calcium Binds Troponin-C
    findings: []
  - id: Reactome:R-HSA-390597
    title: Release Of ADP From Myosin
    findings: []
  - id: Reactome:R-HSA-390598
    title: Myosin Binds ATP
    findings: []
  - id: Reactome:R-HSA-445699
    title: ATP Hydrolysis By Myosin
    findings: []
  - id: Reactome:R-HSA-445700
    title: Myosin Binds ATP
    findings: []
  - id: Reactome:R-HSA-445704
    title: Calcium Binds Caldesmon
    findings: []
  - id: Reactome:R-HSA-445705
    title: Release Of ADP From Myosin
    findings: []
alternative_products:
  - name: 1 (Skeletal muscle, TPM1alpha)
    id: P09493-1
    description: >-
      The canonical striated muscle isoform (284 AA). Also called TPM1alpha. Expressed
      in
      skeletal and cardiac muscle where it regulates actin-myosin interaction during
      muscle
      contraction. Mutations cause familial hypertrophic cardiomyopathy (HCM). GO
      annotations
      for "muscle contraction" and "sarcomere organization" refer primarily to this
      isoform.
  - name: 2 (Smooth muscle)
    id: P09493-2
    sequence_note: VSP_006576, VSP_006578, VSP_006579
    description: >-
      The smooth muscle-specific isoform. Contains alternative exons that confer smooth
      muscle-
      specific properties. Regulates contraction in blood vessels, intestine, and
      other smooth
      muscle tissues. Distinct from striated muscle function of isoform 1.
  - name: 3 (Fibroblast, TM3)
    id: P09493-3
    sequence_note: VSP_006577, VSP_006579
    description: >-
      A cytoskeletal/non-muscle isoform expressed in fibroblasts. Also called TM3.
      Functions
      in non-muscle actin cytoskeleton organization rather than muscle contraction.
      Regulates
      cell morphology, motility, and cytokinesis. GO annotations for "muscle contraction"
      do NOT apply to this isoform.
  - name: '4'
    id: P09493-4
    sequence_note: VSP_006577
    description: >-
      A less characterized isoform. May have cytoskeletal rather than muscle-specific
      functions.
  - name: '5'
    id: P09493-5
    sequence_note: VSP_017498, VSP_017499
    description: >-
      A less characterized isoform. Functional role not well established in the literature.
  - name: 6 (10, TPM1kappa)
    id: P09493-6
    sequence_note: VSP_036064
    description: >-
      Also called TPM1kappa. A non-muscle/cytoskeletal isoform. Functions in actin
      cytoskeleton
      organization in non-muscle cells.
  - name: '7'
    id: P09493-7
    sequence_note: VSP_036064, VSP_006579
    description: >-
      A less characterized isoform with combined features. Functional role not well
      established.
  - name: '8'
    id: P09493-8
    sequence_note: VSP_047297, VSP_047298, VSP_047299,
    description: >-
      A less characterized isoform. Functional role not well established in the literature.
  - name: '9'
    id: P09493-9
    sequence_note: VSP_006579
    description: >-
      A less characterized isoform. Functional role not well established in the literature.
  - name: '10'
    id: P09493-10
    sequence_note: VSP_047299, VSP_047300, VSP_047301
    description: >-
      A less characterized isoform. Functional role not well established in the literature.