MAP7

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0000226 microtubule cytoskeleton organization	IBA GO_REF:0000033	ACCEPT	Summary: MAP7 plays a well-established role in microtubule cytoskeleton organization. The original characterization paper (PMID:8408219) demonstrated that MAP7 is a microtubule-stabilizing protein important during reorganization of microtubules during polarization and differentiation of epithelial cells. Recent structural studies (Adler et al., 2024) confirmed the MTBD binds across the lattice beyond a single tubulin dimer. Reason: Core function of MAP7. The protein binds and stabilizes microtubules via its N-terminal MTBD domain, contributing to cytoskeletal organization. This is well-supported by the original characterization (PMID:8408219) and subsequent structural/functional studies. Supporting Evidence: PMID:8408219 We conclude that E-MAP-115 is a microtubule-stabilizing protein that may play an important role during reorganization of microtubules during polarization and differentiation of epithelial cells. file:human/MAP7/MAP7-deep-research-falcon.md MAP7 is a structural regulator/adaptor on MTs that both stabilizes/bundles MTs and recruits/activates kinesin-1 to the lattice to promote plus-end-directed transport.
GO:0015630 microtubule cytoskeleton	IBA GO_REF:0000033	ACCEPT	Summary: MAP7 localizes to the microtubule cytoskeleton as demonstrated by immunofluorescence and biochemical studies. The original study showed preferential association with perinuclear microtubules in HeLa cells (PMID:8408219). UniProt annotation also notes colocalization on microtubules. Reason: Well-established localization. MAP7 decorates the microtubule lattice as a core part of its function. IBA annotation is appropriate as this is conserved across the MAP7 family. Supporting Evidence: PMID:8408219 In HeLa cells, E-MAP-115 is preferentially associated with subdomains or subsets of perinuclear microtubules.
GO:0000226 microtubule cytoskeleton organization	IEA GO_REF:0000002	ACCEPT	Summary: This IEA annotation from InterPro mapping is consistent with the well-established role of MAP7 in microtubule organization. While redundant with the IBA annotation, it is not incorrect. Reason: Correct annotation consistent with MAP7's core function in microtubule stabilization and organization. Redundancy with IBA is acceptable.
GO:0005856 cytoskeleton	IEA GO_REF:0000044	MARK AS OVER ANNOTATED	Summary: MAP7 is indeed a cytoskeletal protein, specifically associating with microtubules. This is a broad parent term of more specific annotations. Reason: Accurate but general annotation. The more specific microtubule cytoskeleton annotations are more informative but this is not wrong. [2026-08 SL project re-review] Uninformative parent from the UniProt subcellular-location pipeline. The sole source for this annotation is GO_REF:0000044 (UniProtKB-SubCell), and the gene already carries strictly more specific term(s) from independent evidence, namely GO:0005875 microtubule associated complex (TAS) and GO:0005874 microtubule. The term is not false; it is an under-specified location that adds no information over what is already annotated, which is the dominant failure mode of the SL pipeline (see projects/SL.md). Marked over-annotated rather than MODIFY because the more precise term is already present, so there is nothing to replace it with.
GO:0005874 microtubule	IEA GO_REF:0000043	ACCEPT	Summary: MAP7 directly binds microtubules through its N-terminal MTBD domain. This localization is fundamental to its function. ITC measurements indicate KD ~0.94 uM for MAP7 MTBD binding to microtubules (Adler et al., 2024). Reason: Core localization for MAP7. Direct microtubule binding is well-established through multiple experimental approaches including structural studies, binding assays, and immunofluorescence. Supporting Evidence: PMID:8408219 A novel microtubule-binding site has been localized to the basic alpha-helical region in the NH2-terminal domain using in vitro microtubule-binding assays and expression of mutant polypeptides in vivo.
GO:0015630 microtubule cytoskeleton	IEA GO_REF:0000002	ACCEPT	Summary: Consistent with other annotations placing MAP7 at the microtubule cytoskeleton. While redundant with IBA and IDA annotations, this is correct. Reason: Correct annotation, though redundant with higher-quality evidence annotations.
GO:0016323 basolateral plasma membrane	IEA GO_REF:0000044	ACCEPT	Summary: UniProt annotation indicates basolateral cell membrane localization. This is consistent with MAP7's role in epithelial cell polarization, where it redistributes to cortical microtubules organized in spike-like bundles facing intercellular contacts during keratinocyte terminal differentiation (PMID:9989799). Reason: Appropriate for epithelial contexts where MAP7 functions in cell polarity. The localization reflects its role in polarized epithelial cells.
GO:0048471 perinuclear region of cytoplasm	IEA GO_REF:0000044	ACCEPT	Summary: MAP7 shows perinuclear localization in HeLa cells as originally described. The protein associates with perinuclear microtubule subsets. Reason: Well-documented localization from the original characterization paper. Supporting Evidence: PMID:8408219 In HeLa cells, E-MAP-115 is preferentially associated with subdomains or subsets of perinuclear microtubules.
GO:0005515 protein binding	IPI PMID:27018634 Quantitative Mass Spectrometry Identifies Novel Host Binding...	REMOVE	Summary: This annotation comes from a mass spectrometry study identifying MAP7 (ensconsin) as a host binding partner for E. coli type III secretion system effectors NleB1 and EspL. The study confirmed interaction with the microtubule binding domain region. Reason: The term "protein binding" is uninformative and should be replaced with a more specific term. While the study demonstrates physical interaction with bacterial effector proteins, this represents a pathogen-host interaction rather than a core cellular function of MAP7. Furthermore, GO:0005515 provides no mechanistic insight. Bacterial interactions could be annotated more specifically if relevant. Supporting Evidence: PMID:27018634 we identified multiple effectors that interacted with the microtubule associated protein, ensconsin
GO:0005515 protein binding	IPI PMID:32296183 A reference map of the human binary protein interactome.	REMOVE	Summary: This annotation derives from the HuRI high-throughput binary protein interactome study. While MAP7 was detected in protein-protein interactions via Y2H screens, the term "protein binding" is uninformative. Reason: GO:0005515 (protein binding) is too vague to be informative. MAP7's important protein interactions include kinesin-1 binding (which recruits/activates the motor) and tubulin binding. These should be annotated with specific terms like GO:0019894 (kinesin binding) rather than the generic protein binding term. Supporting Evidence: PMID:32296183 With approximately 53,000 protein-protein interactions, HuRI has approximately four times as many such interactions as there are high-quality curated interactions from small-scale studies
GO:0005829 cytosol	IDA GO_REF:0000052	ACCEPT	Summary: Cytosolic localization based on immunofluorescence data from HPA. MAP7 is indeed present in the cytosol where it associates with microtubules. Reason: Appropriate cellular component annotation. MAP7 is a cytosolic protein that associates with the microtubule network.
GO:0015630 microtubule cytoskeleton	IDA GO_REF:0000052	ACCEPT	Summary: Direct experimental evidence (IDA) from immunofluorescence confirming microtubule cytoskeleton localization. This is the highest quality evidence for this localization. Reason: Core localization with experimental support. IDA evidence provides strong validation of MAP7's association with the microtubule cytoskeleton.
GO:0030424 axon	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: MAP7 family proteins have been shown to function in neuronal contexts, particularly in regulating axonal transport through kinesin-1 recruitment. Studies in Drosophila and mouse neurons support axonal localization and function. Reason: While MAP7 can localize to axons and affect axonal transport, its primary and original characterization was as an epithelial MAP. Neuronal function is secondary/pleiotropic. The ISS evidence is appropriate but this should be considered a non-core annotation.
GO:0005102 signaling receptor binding	ISS GO_REF:0000024	REMOVE	Summary: This annotation appears to derive from sequence similarity transfer. However, MAP7's known molecular functions are microtubule binding and kinesin binding/recruitment, not signaling receptor binding. Reason: No strong evidence supports MAP7 functioning as a signaling receptor binding protein. Its established functions are structural (microtubule binding/stabilization) and as an adaptor for kinesin-1 recruitment. This annotation may be an ISS error or over-annotation.
GO:0006970 response to osmotic stress	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: This annotation appears transferred from orthologs. MAP7 has been associated with TRPV4, which is an osmotically-activated channel, but direct involvement in osmotic stress response is not a primary function. Reason: While MAP7 may have indirect roles through its interaction with TRPV4 (an osmosensor), response to osmotic stress is not a core function. The primary roles are microtubule stabilization and kinesin recruitment.
GO:0072659 protein localization to plasma membrane	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: This annotation may relate to MAP7's role in redistributing TRPV4 toward the membrane or its function in cortical microtubule targeting in epithelial polarity. The Wnt5a-Dishevelled pathway involves MAP7 in positioning Dvl at the cell cortex. Reason: While MAP7 can participate in protein localization through its role in kinesin-1 mediated transport and epithelial polarity, this is not a core molecular function. It is a downstream consequence of its microtubule/kinesin activities.
GO:0000226 microtubule cytoskeleton organization	TAS PMID:8408219 Identification and molecular characterization of E-MAP-115, ...	ACCEPT	Summary: The original characterization paper directly supports this annotation. MAP7 stabilizes microtubules and is important for microtubule reorganization during epithelial polarization and differentiation. Reason: Core function with direct literature support. This is well-established from the original characterization and subsequent functional studies. Supporting Evidence: PMID:8408219 We conclude that E-MAP-115 is a microtubule-stabilizing protein that may play an important role during reorganization of microtubules during polarization and differentiation of epithelial cells.
GO:0005198 structural molecule activity	TAS PMID:8408219 Identification and molecular characterization of E-MAP-115, ...	ACCEPT	Summary: MAP7 functions as a structural protein that binds and stabilizes microtubules. Overexpression renders microtubules resistant to nocodazole depolymerization. Reason: Appropriate molecular function term. MAP7 provides structural support to microtubules through its binding and stabilization activity. This is a core function. Supporting Evidence: PMID:8408219 Overexpression of this domain of E-MAP-115 by transfection of fibroblasts lacking significant levels of this protein with its cDNA renders microtubules stable to nocodazole.
GO:0005875 microtubule associated complex	TAS PMID:8408219 Identification and molecular characterization of E-MAP-115, ...	ACCEPT	Summary: MAP7 is a microtubule-associated protein that decorates the microtubule lattice. It forms part of the microtubule-associated protein complex. Reason: Appropriate cellular component annotation. MAP7 is by definition a microtubule-associated protein, as established in the original characterization. Supporting Evidence: PMID:8408219 A novel microtubule-associated protein (MAP) of M(r) 115,000 has been identified
GO:0007163 establishment or maintenance of cell polarity	TAS PMID:8408219 Identification and molecular characterization of E-MAP-115, ...	ACCEPT	Summary: MAP7 plays a role in epithelial cell polarization. The original paper showed increased expression when Caco-2 cells polarize and form blisters. Subsequent work established roles in Wnt5a-Dishevelled signaling for cortical polarity (Kikuchi et al., 2018). Reason: Core biological process for MAP7, especially in epithelial cells. Its role in microtubule reorganization during polarization and differentiation is well-documented. Supporting Evidence: PMID:8408219 In Caco-2 cells, labeling for E-MAP-115 increases when they polarize and form blisters.
GO:0008017 microtubule binding	IDA PMID:8408219 Identification and molecular characterization of E-MAP-115, ...	NEW	Summary: MAP7 directly binds microtubules via its N-terminal microtubule-binding domain (MTBD, ~residues 59-170). This was demonstrated through in vitro binding assays and mutational analysis in the original characterization. Recent structural work measured KD ~0.94 uM for MTBD-microtubule binding. Reason: This is a core molecular function of MAP7 that should be explicitly annotated. The original paper demonstrated microtubule binding through direct biochemical assays. Supporting Evidence: PMID:8408219 A novel microtubule-binding site has been localized to the basic alpha-helical region in the NH2-terminal domain using in vitro microtubule-binding assays and expression of mutant polypeptides in vivo. file:human/MAP7/MAP7-deep-research-falcon.md MAP7 MTBD-MT binding KD ~0.94 uM (ITC) with a stoichiometry of ~0.5 per tubulin tetramer context; binding extends beyond a single tubulin dimer and involves tubulin C-terminal tails.
GO:0019894 kinesin binding	IDA DOI:10.1038/s41467-018-03909-2	NEW	Summary: MAP7 binds kinesin-1 via its C-terminal region and recruits/activates the motor for plus-end-directed transport. This interaction is well-characterized and represents a core molecular function. MAP7 increases kinesin-1 landing rates ~15-fold (Monroy et al., 2018). Reason: Core molecular function that distinguishes MAP7 from other MAPs. The C-terminal kinesin-1 binding activity is essential for its role in regulating microtubule-based transport. This should be explicitly annotated. Supporting Evidence: file:human/MAP7/MAP7-deep-research-falcon.md MAP7 increases K560 (kinesin-1) landing rate ~15-fold; lowers KmMT (1.46 +/- 0.21 uM to 0.27 +/- 0.04 uM); slightly increases processivity (~874 to ~984 nm) and decreases velocity (~434 to ~328 nm/s).
GO:0007026 negative regulation of microtubule depolymerization	IDA PMID:8408219 Identification and molecular characterization of E-MAP-115, ...	NEW	Summary: MAP7 stabilizes microtubules against depolymerization. Overexpression renders microtubules resistant to nocodazole, a microtubule depolymerizing drug. Reason: Core function - MAP7 is explicitly described as a microtubule-stabilizing protein. The nocodazole resistance experiment directly demonstrates this stabilization activity. Supporting Evidence: PMID:8408219 Overexpression of this domain of E-MAP-115 by transfection of fibroblasts lacking significant levels of this protein with its cDNA renders microtubules stable to nocodazole.

Gene Description

Existing Annotations Review

Core Functions

MAP7 binds microtubules via its N-terminal MTBD (residues ~59-170). This binding is essential for its role as a microtubule-associated protein and enables its stabilization and motor recruitment functions.

MAP7's C-terminal region binds and recruits kinesin-1 to microtubules, promoting plus-end-directed cargo transport. This distinguishes MAP7 from other MAPs and underlies its role in intracellular transport regulation.

MAP7 provides structural support to microtubules by binding and stabilizing them against depolymerization (e.g., resistance to nocodazole). This is a core activity of the protein.

References

Deep Research

Cyberian

Falcon

OpenAI

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