TIMM50

UniProt ID: Q3ZCQ8
Organism: Homo sapiens
Review Status: COMPLETE
πŸ“ Provide Detailed Feedback

Gene Description

TIMM50 encodes the single-pass mitochondrial inner membrane Tim50 subunit of the TIM23 presequence translocase. TIMM50 acts from the intermembrane-space side as a primary presequence receptor and gatekeeper for TIM23-dependent import of transit peptide-containing precursor proteins, while its reported phosphatase, nuclear Tim50a, and calpain-associated roles are secondary or insufficiently established as core human TIMM50 functions.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0030150 protein import into mitochondrial matrix
IBA
GO_REF:0000033
ACCEPT
Summary: Correct and core. TIMM50 is the TIM23 presequence receptor/gatekeeper needed for import of transit peptide-containing precursors through the inner membrane toward the matrix or IMM sorting pathway.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 primarily acts on **presequence-containing precursor proteins**, which constitute a large fraction of the mitochondrial proteome and are imported through the TIM23 pathway for matrix delivery or IMM insertion.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0005744 TIM23 mitochondrial import inner membrane translocase complex
IBA
GO_REF:0000033
ACCEPT
Summary: Correct and core. TIMM50 is a core TIM23 complex subunit that directly coordinates presequence handoff and channel gating.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
PMID:15044455
complex with human Tim23. Down-regulation of human Tim50 expression by RNA
GO:0004722 protein serine/threonine phosphatase activity
IEA
GO_REF:0000117
KEEP AS NON CORE
Summary: Direct assays reported phosphatase activity, but current synthesis indicates the physiological substrate and in vivo relevance remain unclear; TIMM50 should be curated primarily as a TIM23 presequence receptor/gatekeeper.
Reason: The phosphatase activity is not the core validated biological function of TIMM50 and has no established physiological substrate in the import pathway.
Supporting Evidence:
PMID:15044455
demonstrate that human Tim50 possesses phosphatase activity and is present in a
file:human/TIMM50/TIMM50-deep-research-falcon.md
Therefore, based on available evidence, the primary validated function remains **protein import receptor/gating**, not a defined metabolic reaction with established substrates.
GO:0005743 mitochondrial inner membrane
IEA
GO_REF:0000044
ACCEPT
Summary: Correct. Canonical TIMM50 is a single-pass mitochondrial inner membrane protein with its receptor/gating domain exposed to the intermembrane space.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0016607 nuclear speck
IEA
Q3ZCQ8-2
GO_REF:0000044
KEEP AS NON CORE
Summary: Supported for the Tim50a isoform, but not the core function of the canonical mitochondrial TIMM50 protein.
Reason: Track as isoform-specific, non-core nuclear localization; canonical TIMM50 function is mitochondrial TIM23 import.
Supporting Evidence:
PMID:16008839
cytoplasm and mitochondria, Tim50a is strictly nuclear and is enriched in
GO:0005515 protein binding
IPI
PMID:12620389
Novel raf kinase protein-protein interactions found by an ex...
MARK AS OVER ANNOTATED
Summary: Protein binding is true but uninformative for TIMM50. The biologically meaningful interaction context is TIM23 presequence receptor/gating and TIMM23/TIM17 complex membership.
Reason: Replace generic interaction capture with TIM23 complex membership and presequence/targeting-sequence binding where supported.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0005515 protein binding
IPI
PMID:25852190
Integrative analysis of kinase networks in TRAIL-induced apo...
MARK AS OVER ANNOTATED
Summary: Protein binding is true but uninformative for TIMM50. The biologically meaningful interaction context is TIM23 presequence receptor/gating and TIMM23/TIM17 complex membership.
Reason: Replace generic interaction capture with TIM23 complex membership and presequence/targeting-sequence binding where supported.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0005515 protein binding
IPI
PMID:31980649
Extensive rewiring of the EGFR network in colorectal cancer ...
MARK AS OVER ANNOTATED
Summary: Protein binding is true but uninformative for TIMM50. The biologically meaningful interaction context is TIM23 presequence receptor/gating and TIMM23/TIM17 complex membership.
Reason: Replace generic interaction capture with TIM23 complex membership and presequence/targeting-sequence binding where supported.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0005515 protein binding
IPI
PMID:37045861
Interactome dynamics of RAF1-BRAF kinase monomers and dimers...
MARK AS OVER ANNOTATED
Summary: Protein binding is true but uninformative for TIMM50. The biologically meaningful interaction context is TIM23 presequence receptor/gating and TIMM23/TIM17 complex membership.
Reason: Replace generic interaction capture with TIM23 complex membership and presequence/targeting-sequence binding where supported.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0005743 mitochondrial inner membrane
IDA
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
ACCEPT
Summary: Correct. Canonical TIMM50 is a single-pass mitochondrial inner membrane protein with its receptor/gating domain exposed to the intermembrane space.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0005743 mitochondrial inner membrane
NAS
PMID:10339406
Genetic and structural characterization of the human mitocho...
ACCEPT
Summary: Correct. Canonical TIMM50 is a single-pass mitochondrial inner membrane protein with its receptor/gating domain exposed to the intermembrane space.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0005744 TIM23 mitochondrial import inner membrane translocase complex
NAS
PMID:10339406
Genetic and structural characterization of the human mitocho...
ACCEPT
Summary: Correct and core. TIMM50 is a core TIM23 complex subunit that directly coordinates presequence handoff and channel gating.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
PMID:15044455
complex with human Tim23. Down-regulation of human Tim50 expression by RNA
GO:0006886 intracellular protein transport
NAS
PMID:10339406
Genetic and structural characterization of the human mitocho...
MARK AS OVER ANNOTATED
Summary: Correct pathway family but too broad. TIMM50 specifically mediates TIM23-dependent mitochondrial presequence protein import rather than general intracellular protein transport.
Reason: Use mitochondrial matrix import/TIM23 terms instead of generic intracellular transport.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 primarily acts on **presequence-containing precursor proteins**, which constitute a large fraction of the mitochondrial proteome and are imported through the TIM23 pathway for matrix delivery or IMM insertion.
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0005654 nucleoplasm
IDA
GO_REF:0000052
MARK AS OVER ANNOTATED
Summary: Broad nuclear localization is less informative than the isoform-specific nuclear speck evidence for Tim50a and is not the canonical TIMM50 localization.
Reason: Use isoform-specific nuclear speck annotation for Tim50a; canonical TIMM50 is an inner mitochondrial membrane TIM23 subunit.
Supporting Evidence:
PMID:16008839
cytoplasm and mitochondria, Tim50a is strictly nuclear and is enriched in
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0005739 mitochondrion
IDA
GO_REF:0000052
MARK AS OVER ANNOTATED
Summary: Correct but broad. Canonical TIMM50 is specifically an inner mitochondrial membrane TIM23 complex subunit.
Reason: Prefer mitochondrial inner membrane and TIM23 complex annotations over generic mitochondrion.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0030150 protein import into mitochondrial matrix
IDA
PMID:38828998
Reduced Protein Import via TIM23 SORT Drives Disease Patholo...
ACCEPT
Summary: Correct and core. TIMM50 is the TIM23 presequence receptor/gatekeeper needed for import of transit peptide-containing precursors through the inner membrane toward the matrix or IMM sorting pathway.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 primarily acts on **presequence-containing precursor proteins**, which constitute a large fraction of the mitochondrial proteome and are imported through the TIM23 pathway for matrix delivery or IMM insertion.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0005739 mitochondrion
HTP
PMID:34800366
Quantitative high-confidence human mitochondrial proteome an...
MARK AS OVER ANNOTATED
Summary: Correct but broad. Canonical TIMM50 is specifically an inner mitochondrial membrane TIM23 complex subunit.
Reason: Prefer mitochondrial inner membrane and TIM23 complex annotations over generic mitochondrion.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0005744 TIM23 mitochondrial import inner membrane translocase complex
IDA
PMID:30598479
ROMO1 is a constituent of the human presequence translocase ...
ACCEPT
Summary: Correct and core. TIMM50 is a core TIM23 complex subunit that directly coordinates presequence handoff and channel gating.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
PMID:15044455
complex with human Tim23. Down-regulation of human Tim50 expression by RNA
GO:0005739 mitochondrion
IDA
PMID:32848200
Ttm50 facilitates calpain activation by anchoring it to calc...
MARK AS OVER ANNOTATED
Summary: Correct but broad. Canonical TIMM50 is specifically an inner mitochondrial membrane TIM23 complex subunit.
Reason: Prefer mitochondrial inner membrane and TIM23 complex annotations over generic mitochondrion.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.
GO:0005783 endoplasmic reticulum
IDA
PMID:32848200
Ttm50 facilitates calpain activation by anchoring it to calc...
MARK AS OVER ANNOTATED
Summary: The cited FlyBase-sourced study supports a Drosophila Ttm50 calpain/ER-Golgi calcium-store context, but the human TIMM50 synthesis supports mitochondrial TIM23 import as the established function.
Reason: PMID:32848200 studies Drosophila Ttm50, not human TIMM50. Do not treat the noncanonical Ttm50 calpain calcium-store finding as a core human TIMM50 activity or localization without human TIMM50-specific support.
Supporting Evidence:
PMID:32848200
GluRIIA at the Drosophila neuromuscular junction as a readout, we uncovered that
PMID:32848200
stores Golgi and endoplasmic reticulum (ER), and Ttm50 interacts with calpain
PMID:32848200
magnitude. Our findings reveal the regulation of calpain activation by Ttm50,
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0005794 Golgi apparatus
IDA
PMID:32848200
Ttm50 facilitates calpain activation by anchoring it to calc...
MARK AS OVER ANNOTATED
Summary: The cited FlyBase-sourced study supports a Drosophila Ttm50 calpain/ER-Golgi calcium-store context, but the human TIMM50 synthesis supports mitochondrial TIM23 import as the established function.
Reason: PMID:32848200 studies Drosophila Ttm50, not human TIMM50. Do not treat the noncanonical Ttm50 calpain calcium-store finding as a core human TIMM50 activity or localization without human TIMM50-specific support.
Supporting Evidence:
PMID:32848200
GluRIIA at the Drosophila neuromuscular junction as a readout, we uncovered that
PMID:32848200
stores Golgi and endoplasmic reticulum (ER), and Ttm50 interacts with calpain
PMID:32848200
magnitude. Our findings reveal the regulation of calpain activation by Ttm50,
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0140608 cysteine-type endopeptidase activator activity
IDA
PMID:32848200
Ttm50 facilitates calpain activation by anchoring it to calc...
MARK AS OVER ANNOTATED
Summary: The cited FlyBase-sourced study supports a Drosophila Ttm50 calpain/ER-Golgi calcium-store context, but the human TIMM50 synthesis supports mitochondrial TIM23 import as the established function.
Reason: PMID:32848200 studies Drosophila Ttm50, not human TIMM50. Do not treat the noncanonical Ttm50 calpain calcium-store finding as a core human TIMM50 activity or localization without human TIMM50-specific support.
Supporting Evidence:
PMID:32848200
GluRIIA at the Drosophila neuromuscular junction as a readout, we uncovered that
PMID:32848200
stores Golgi and endoplasmic reticulum (ER), and Ttm50 interacts with calpain
PMID:32848200
magnitude. Our findings reveal the regulation of calpain activation by Ttm50,
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0001836 release of cytochrome c from mitochondria
IDA
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
KEEP AS NON CORE
Summary: Supported as a downstream consequence of TIMM50 depletion and mitochondrial membrane dysfunction, but it is not the core molecular/cellular role of TIMM50.
Reason: TIMM50 loss can accelerate cytochrome c release, but TIMM50 itself is primarily a TIM23 import receptor/gatekeeper.
Supporting Evidence:
PMID:15044455
accelerating the release of cytochrome c from the mitochondria. Furthermore,
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0004721 phosphoprotein phosphatase activity
IDA
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
KEEP AS NON CORE
Summary: Direct assays reported phosphatase activity, but current synthesis indicates the physiological substrate and in vivo relevance remain unclear; TIMM50 should be curated primarily as a TIM23 presequence receptor/gatekeeper.
Reason: The phosphatase activity is not the core validated biological function of TIMM50 and has no established physiological substrate in the import pathway.
Supporting Evidence:
PMID:15044455
demonstrate that human Tim50 possesses phosphatase activity and is present in a
file:human/TIMM50/TIMM50-deep-research-falcon.md
Therefore, based on available evidence, the primary validated function remains **protein import receptor/gating**, not a defined metabolic reaction with established substrates.
GO:0005134 interleukin-2 receptor binding
IDA
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
REMOVE
Summary: The cited Tim50 paper and Falcon synthesis do not support an interleukin-2 receptor binding activity for TIMM50; the established molecular role is TIM23 presequence receptor/gating.
Reason: PMID:15044455 describes human Tim50 as a mitochondrial translocator/TIM23-associated protein and contains no mention of IL-2 receptor binding. This annotation appears to be a database misattribution, because a mitochondrial inner-membrane translocase subunit is not expected to function as an IL-2 receptor ligand or receptor-binding protein.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Therefore, based on available evidence, the primary validated function remains **protein import receptor/gating**, not a defined metabolic reaction with established substrates.
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0005744 TIM23 mitochondrial import inner membrane translocase complex
IPI
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
ACCEPT
Summary: Correct and core. TIMM50 is a core TIM23 complex subunit that directly coordinates presequence handoff and channel gating.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
PMID:15044455
complex with human Tim23. Down-regulation of human Tim50 expression by RNA
GO:0004722 protein serine/threonine phosphatase activity
IDA
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
KEEP AS NON CORE
Summary: Direct assays reported phosphatase activity, but current synthesis indicates the physiological substrate and in vivo relevance remain unclear; TIMM50 should be curated primarily as a TIM23 presequence receptor/gatekeeper.
Reason: The phosphatase activity is not the core validated biological function of TIMM50 and has no established physiological substrate in the import pathway.
Supporting Evidence:
PMID:15044455
demonstrate that human Tim50 possesses phosphatase activity and is present in a
file:human/TIMM50/TIMM50-deep-research-falcon.md
Therefore, based on available evidence, the primary validated function remains **protein import receptor/gating**, not a defined metabolic reaction with established substrates.
GO:0004725 protein tyrosine phosphatase activity
IDA
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
KEEP AS NON CORE
Summary: Direct assays reported phosphatase activity, but current synthesis indicates the physiological substrate and in vivo relevance remain unclear; TIMM50 should be curated primarily as a TIM23 presequence receptor/gatekeeper.
Reason: The phosphatase activity is not the core validated biological function of TIMM50 and has no established physiological substrate in the import pathway.
Supporting Evidence:
PMID:15044455
demonstrate that human Tim50 possesses phosphatase activity and is present in a
file:human/TIMM50/TIMM50-deep-research-falcon.md
Therefore, based on available evidence, the primary validated function remains **protein import receptor/gating**, not a defined metabolic reaction with established substrates.
GO:0005515 protein binding
IPI
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
MARK AS OVER ANNOTATED
Summary: Protein binding is true but uninformative for TIMM50. The biologically meaningful interaction context is TIM23 presequence receptor/gating and TIMM23/TIM17 complex membership.
Reason: Replace generic interaction capture with TIM23 complex membership and presequence/targeting-sequence binding where supported.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
GO:0007006 mitochondrial membrane organization
IMP
PMID:15044455
Tim50, a component of the mitochondrial translocator, regula...
KEEP AS NON CORE
Summary: Supported as a cellular consequence of TIMM50 loss causing mitochondrial membrane permeabilization/dysfunction, but it is downstream of the core TIM23 import role.
Reason: Keep as non-core because membrane organization phenotypes arise from impaired mitochondrial import/integrity rather than a direct membrane-organizing function.
Supporting Evidence:
PMID:15044455
indicate that loss of Tim50 in vertebrates causes mitochondrial membrane
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
GO:0016607 nuclear speck
IDA
Q3ZCQ8-2
PMID:16008839
Tim50a, a nuclear isoform of the mitochondrial Tim50, intera...
KEEP AS NON CORE
Summary: Supported for the Tim50a isoform, but not the core function of the canonical mitochondrial TIMM50 protein.
Reason: Track as isoform-specific, non-core nuclear localization; canonical TIMM50 function is mitochondrial TIM23 import.
Supporting Evidence:
PMID:16008839
cytoplasm and mitochondria, Tim50a is strictly nuclear and is enriched in
GO:0043021 ribonucleoprotein complex binding
IDA
Q3ZCQ8-2
PMID:16008839
Tim50a, a nuclear isoform of the mitochondrial Tim50, intera...
KEEP AS NON CORE
Summary: Supported for the nuclear Tim50a isoform, which interacts with snRNP-associated proteins, but this is not the canonical mitochondrial import function.
Reason: Keep as an isoform-specific non-core activity distinct from TIM23 presequence import.
Supporting Evidence:
PMID:16008839
In addition to coilin, Tim50a interacts with snRNPs and
PMID:16008839
cytoplasm and mitochondria, Tim50a is strictly nuclear and is enriched in
GO:0140436 mitochondrial signal sequence receptor activity
NAS
file:human/TIMM50/TIMM50-deep-research-falcon.md
NEW
Summary: TIMM50 is described as the primary inner-membrane presequence receptor for TIM23 substrates, so mitochondrial signal sequence receptor activity (GO:0140436, the replacement for the obsolete GO:0030943) captures its core molecular function better than generic protein binding.
Reason: Existing GOA lacks a specific molecular-function term for TIMM50 presequence/targeting-signal receptor activity.
Supporting Evidence:
file:human/TIMM50/TIMM50-deep-research-falcon.md
Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
file:human/TIMM50/TIMM50-deep-research-falcon.md
TIMM50 primarily acts on **presequence-containing precursor proteins**, which constitute a large fraction of the mitochondrial proteome and are imported through the TIM23 pathway for matrix delivery or IMM insertion.
file:human/TIMM50/TIMM50-deep-research-falcon.md
This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.

Core Functions

TIMM50 is the inner-membrane TIM23 presequence receptor and gatekeeper that captures transit peptide-containing mitochondrial precursors on the intermembrane-space side, coordinates TIM23 channel gating, and supports import into the matrix or IMM sorting pathway.

Supporting Evidence:
  • file:human/TIMM50/TIMM50-deep-research-falcon.md
    Tim50 is widely regarded as the **primary presequence receptor at the inner membrane**, positioned in the **intermembrane space (IMS)** to receive precursors emerging from the TOM pore and coordinate their entry into TIM23.
  • file:human/TIMM50/TIMM50-deep-research-falcon.md
    TIMM50 primarily acts on **presequence-containing precursor proteins**, which constitute a large fraction of the mitochondrial proteome and are imported through the TIM23 pathway for matrix delivery or IMM insertion.
  • file:human/TIMM50/TIMM50-deep-research-falcon.md
    This receptor/gating logic is supported by direct presequence-binding mapping and the conclusion that Tim50 binding to Tim23 can induce channel closure when no substrate is being transported.
  • file:human/TIMM50/TIMM50-deep-research-falcon.md
    TIMM50 is a **single-pass IMM protein** with an N-terminal mitochondrial targeting sequence, a transmembrane anchor, and a large **IMS-exposed hydrophilic domain** that mediates receptor/gating functions.

References

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Suggested Questions for Experts

Q: What are the physiological substrates, if any, of the TIMM50 phosphatase-like domain in human cells?

Q: Which human TIM23SORT substrates depend most strongly on TIMM50 presequence recognition or gating?

Q: Is the Tim50a nuclear speck/snRNP role broadly physiological or restricted to specific transformed or neural cell contexts?

Suggested Experiments

Experiment: Use TIMM50 rescue mutants affecting presequence-binding and TIMM23-interaction surfaces in TIMM50-deficient human cells, then measure TIM23 complex assembly, channel gating, and import of TIM23MOTOR versus TIM23SORT reporter substrates.

Hypothesis: TIMM50 presequence binding and channel-gating surfaces are separable.

Experiment: Compare phosphatase-dead TIMM50 mutants with receptor/gating mutants for rescue of matrix import, IMM sorting, TIM23 complex stability, and patient-cell respiratory phenotypes.

Hypothesis: TIMM50 phosphatase-like activity is dispensable for most TIM23 import functions.

Deep Research

Falcon

(TIMM50-deep-research-falcon.md)

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