TOMM22

UniProt ID: Q9NS69
Organism: Homo sapiens
Review Status: COMPLETE
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Gene Description

TOMM22 encodes hTom22, a single-pass mitochondrial outer membrane receptor and scaffold subunit of the TOM complex. TOMM22 recognizes mitochondrial precursor proteins, helps transfer them toward the TOMM40 pore, and supports TOM complex assembly and stability; its transporter annotation is best interpreted as contribution to TOM complex protein import rather than standalone pore activity.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0030150 protein import into mitochondrial matrix
IBA
GO_REF:0000033
ACCEPT
Summary: Correct as a TOM-complex entry step for matrix-destined mitochondrial preproteins. TOMM22 is a receptor/scaffold that recognizes precursors and transfers them toward the TOMM40 pore before downstream inner-membrane import.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
The **TOM complex** is the primary entry gate for most nucleus-encoded mitochondrial proteins into mitochondria.
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
GO:0005742 mitochondrial outer membrane translocase complex
IBA
GO_REF:0000033
ACCEPT
Summary: Correct. TOMM22 is a core receptor/scaffold subunit of the TOM complex / mitochondrial outer membrane translocase complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Human **TOMM22 (Q9NS69)** encodes **hTom22**, a **single-pass outer mitochondrial membrane** subunit of the TOM complex that acts as the **central receptor** and an **assembly-organizing scaffold**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
2) an **organizational scaffold** required for correct **TOM complex assembly** and stability.
GO:0008320 protein transmembrane transporter activity
IBA
GO_REF:0000033
ACCEPT
Summary: Accepted as contribution to TOM complex protein transmembrane transporter activity. TOMM22 is the receptor/scaffold that transfers precursors toward the TOMM40 pore, not the pore-forming subunit by itself.
Reason: Retain only as complex contribution; TOMM40 is the conducting pore, whereas TOMM22 provides receptor/scaffold function needed for import.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
The 2024 PNAS Nexus study (Su et al.) reports a **human TOM holo complex cryo-EM structure** including intact Tom20 at **~6 Γ…** and explicitly frames Tom22 as one of the TOM receptors that recognize targeting signals and collaborate in translocation.
GO:0005741 mitochondrial outer membrane
IEA
GO_REF:0000120
ACCEPT
Summary: Correct. TOMM22 is a single-pass mitochondrial outer membrane component of the TOM complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0006886 intracellular protein transport
IEA
GO_REF:0000002
MARK AS OVER ANNOTATED
Summary: Correct pathway family but too broad. TOMM22 specifically functions in TOM-complex mitochondrial protein import.
Reason: Use mitochondrial protein import/localization and TOM complex terms rather than generic intracellular protein transport.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
The **TOM complex** is the primary entry gate for most nucleus-encoded mitochondrial proteins into mitochondria.
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
GO:0005515 protein binding
IPI
PMID:12198123
Insertion and assembly of human tom7 into the preprotein tra...
MARK AS OVER ANNOTATED
Summary: Protein binding is too generic for TOMM22. The informative functions are precursor/targeting-sequence recognition and TOM complex scaffold membership.
Reason: Documented interactions should be captured by TOM complex and targeting-sequence/preprotein receptor annotations rather than generic protein binding.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Within this machinery, **TOMM22/hTom22** is described as the **central receptor** of the TOM complex, functioning both as:
file:human/TOMM22/TOMM22-deep-research-falcon.md
1) a **major preprotein-binding site** and transfer platform, and
GO:0005515 protein binding
IPI
PMID:25556234
New host factors important for respiratory syncytial virus (...
MARK AS OVER ANNOTATED
Summary: Protein binding is too generic for TOMM22. The informative functions are precursor/targeting-sequence recognition and TOM complex scaffold membership.
Reason: Documented interactions should be captured by TOM complex and targeting-sequence/preprotein receptor annotations rather than generic protein binding.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Within this machinery, **TOMM22/hTom22** is described as the **central receptor** of the TOM complex, functioning both as:
file:human/TOMM22/TOMM22-deep-research-falcon.md
1) a **major preprotein-binding site** and transfer platform, and
GO:0005515 protein binding
IPI
PMID:32296183
A reference map of the human binary protein interactome.
MARK AS OVER ANNOTATED
Summary: Protein binding is too generic for TOMM22. The informative functions are precursor/targeting-sequence recognition and TOM complex scaffold membership.
Reason: Documented interactions should be captured by TOM complex and targeting-sequence/preprotein receptor annotations rather than generic protein binding.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Within this machinery, **TOMM22/hTom22** is described as the **central receptor** of the TOM complex, functioning both as:
file:human/TOMM22/TOMM22-deep-research-falcon.md
1) a **major preprotein-binding site** and transfer platform, and
GO:0005515 protein binding
IPI
PMID:32814053
Interactome Mapping Provides a Network of Neurodegenerative ...
MARK AS OVER ANNOTATED
Summary: Protein binding is too generic for TOMM22. The informative functions are precursor/targeting-sequence recognition and TOM complex scaffold membership.
Reason: Documented interactions should be captured by TOM complex and targeting-sequence/preprotein receptor annotations rather than generic protein binding.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Within this machinery, **TOMM22/hTom22** is described as the **central receptor** of the TOM complex, functioning both as:
file:human/TOMM22/TOMM22-deep-research-falcon.md
1) a **major preprotein-binding site** and transfer platform, and
GO:0030150 protein import into mitochondrial matrix
TAS
PMID:10982837
Identification and functional analysis of human Tom22 for pr...
ACCEPT
Summary: Correct as a TOM-complex entry step for matrix-destined mitochondrial preproteins. TOMM22 is a receptor/scaffold that recognizes precursors and transfers them toward the TOMM40 pore before downstream inner-membrane import.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
The **TOM complex** is the primary entry gate for most nucleus-encoded mitochondrial proteins into mitochondria.
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
GO:0005739 mitochondrion
IDA
GO_REF:0000052
MARK AS OVER ANNOTATED
Summary: Correct but broad. TOMM22 is specifically localized to the mitochondrial outer membrane/TOM complex.
Reason: Prefer mitochondrial outer membrane and TOM complex annotations over generic mitochondrion.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0005741 mitochondrial outer membrane
EXP
PMID:10982837
Identification and functional analysis of human Tom22 for pr...
ACCEPT
Summary: Correct. TOMM22 is a single-pass mitochondrial outer membrane component of the TOM complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0030150 protein import into mitochondrial matrix
IDA
PMID:15644312
Dissection of the mitochondrial import and assembly pathway ...
ACCEPT
Summary: Correct as a TOM-complex entry step for matrix-destined mitochondrial preproteins. TOMM22 is a receptor/scaffold that recognizes precursors and transfers them toward the TOMM40 pore before downstream inner-membrane import.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
The **TOM complex** is the primary entry gate for most nucleus-encoded mitochondrial proteins into mitochondria.
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
GO:0005741 mitochondrial outer membrane
NAS
PMID:18331822
Identification of Tom5 and Tom6 in the preprotein translocas...
ACCEPT
Summary: Correct. TOMM22 is a single-pass mitochondrial outer membrane component of the TOM complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0045040 protein insertion into mitochondrial outer membrane
NAS
PMID:18331822
Identification of Tom5 and Tom6 in the preprotein translocas...
KEEP AS NON CORE
Summary: Supported as a TOM-complex assembly/import pathway role, but TOMM22 is primarily the TOM receptor/scaffold rather than a general outer-membrane protein insertase.
Reason: Keep as non-core because TOMM22 affects TOM assembly and insertion of TOM-related substrates, while the core function is preprotein receptor/scaffold activity.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
2) an **organizational scaffold** required for correct **TOM complex assembly** and stability.
file:human/TOMM22/TOMM22-deep-research-falcon.md
Functional perturbation evidence supports a role for Tom22 as an assembly determinant and, in some contexts, a rate-limiting factor for full TOM complex formation.
GO:0140596 TOM complex
NAS
PMID:18331822
Identification of Tom5 and Tom6 in the preprotein translocas...
ACCEPT
Summary: Correct. TOMM22 is a core receptor/scaffold subunit of the TOM complex / mitochondrial outer membrane translocase complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Human **TOMM22 (Q9NS69)** encodes **hTom22**, a **single-pass outer mitochondrial membrane** subunit of the TOM complex that acts as the **central receptor** and an **assembly-organizing scaffold**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
2) an **organizational scaffold** required for correct **TOM complex assembly** and stability.
GO:0005739 mitochondrion
HTP
PMID:34800366
Quantitative high-confidence human mitochondrial proteome an...
MARK AS OVER ANNOTATED
Summary: Correct but broad. TOMM22 is specifically localized to the mitochondrial outer membrane/TOM complex.
Reason: Prefer mitochondrial outer membrane and TOM complex annotations over generic mitochondrion.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0030943 mitochondrion targeting sequence binding
IDA
PMID:35733257
Structural basis of Tom20 and Tom22 cytosolic domains as the...
MODIFY
Summary: Correct and core. TOMM22 functions as a major mitochondrial preprotein/targeting-signal binding receptor in the TOM complex.
Reason: GO:0030943 (mitochondrion targeting sequence binding) is obsolete in the current GO release (consider GO:0140436 / GO:0008320). TOMM22 is the central TOM receptor for presequences, so the receptor MF GO:0140436 is the designated replacement.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
1) a **major preprotein-binding site** and transfer platform, and
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
The 2024 PNAS Nexus study (Su et al.) reports a **human TOM holo complex cryo-EM structure** including intact Tom20 at **~6 Γ…** and explicitly frames Tom22 as one of the TOM receptors that recognize targeting signals and collaborate in translocation.
GO:0016020 membrane
HDA
PMID:19946888
Defining the membrane proteome of NK cells.
MARK AS OVER ANNOTATED
Summary: Correct but very broad. TOMM22 is specifically a mitochondrial outer membrane TOM complex subunit.
Reason: Use mitochondrial outer membrane/TOM complex annotations instead of generic membrane.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0005741 mitochondrial outer membrane
TAS
Reactome:R-HSA-5205661
ACCEPT
Summary: Correct. TOMM22 is a single-pass mitochondrial outer membrane component of the TOM complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0016020 membrane
IDA
PMID:15644312
Dissection of the mitochondrial import and assembly pathway ...
MARK AS OVER ANNOTATED
Summary: Correct but very broad. TOMM22 is specifically a mitochondrial outer membrane TOM complex subunit.
Reason: Use mitochondrial outer membrane/TOM complex annotations instead of generic membrane.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.
GO:0008320 protein transmembrane transporter activity
ISS
GO_REF:0000024
ACCEPT
Summary: Accepted as contribution to TOM complex protein transmembrane transporter activity. TOMM22 is the receptor/scaffold that transfers precursors toward the TOMM40 pore, not the pore-forming subunit by itself.
Reason: Retain only as complex contribution; TOMM40 is the conducting pore, whereas TOMM22 provides receptor/scaffold function needed for import.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
The 2024 PNAS Nexus study (Su et al.) reports a **human TOM holo complex cryo-EM structure** including intact Tom20 at **~6 Γ…** and explicitly frames Tom22 as one of the TOM receptors that recognize targeting signals and collaborate in translocation.
GO:0005742 mitochondrial outer membrane translocase complex
IDA
PMID:12198123
Insertion and assembly of human tom7 into the preprotein tra...
ACCEPT
Summary: Correct. TOMM22 is a core receptor/scaffold subunit of the TOM complex / mitochondrial outer membrane translocase complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Human **TOMM22 (Q9NS69)** encodes **hTom22**, a **single-pass outer mitochondrial membrane** subunit of the TOM complex that acts as the **central receptor** and an **assembly-organizing scaffold**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
2) an **organizational scaffold** required for correct **TOM complex assembly** and stability.
GO:0005742 mitochondrial outer membrane translocase complex
IDA
PMID:15644312
Dissection of the mitochondrial import and assembly pathway ...
ACCEPT
Summary: Correct. TOMM22 is a core receptor/scaffold subunit of the TOM complex / mitochondrial outer membrane translocase complex.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Human **TOMM22 (Q9NS69)** encodes **hTom22**, a **single-pass outer mitochondrial membrane** subunit of the TOM complex that acts as the **central receptor** and an **assembly-organizing scaffold**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
2) an **organizational scaffold** required for correct **TOM complex assembly** and stability.
GO:0008320 protein transmembrane transporter activity
TAS
PMID:15644312
Dissection of the mitochondrial import and assembly pathway ...
ACCEPT
Summary: Accepted as contribution to TOM complex protein transmembrane transporter activity. TOMM22 is the receptor/scaffold that transfers precursors toward the TOMM40 pore, not the pore-forming subunit by itself.
Reason: Retain only as complex contribution; TOMM40 is the conducting pore, whereas TOMM22 provides receptor/scaffold function needed for import.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
file:human/TOMM22/TOMM22-deep-research-falcon.md
The 2024 PNAS Nexus study (Su et al.) reports a **human TOM holo complex cryo-EM structure** including intact Tom20 at **~6 Γ…** and explicitly frames Tom22 as one of the TOM receptors that recognize targeting signals and collaborate in translocation.
GO:0005515 protein binding
IPI
PMID:14557246
AIP is a mitochondrial import mediator that binds to both im...
MARK AS OVER ANNOTATED
Summary: Protein binding is too generic for TOMM22. The informative functions are precursor/targeting-sequence recognition and TOM complex scaffold membership.
Reason: Documented interactions should be captured by TOM complex and targeting-sequence/preprotein receptor annotations rather than generic protein binding.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
Within this machinery, **TOMM22/hTom22** is described as the **central receptor** of the TOM complex, functioning both as:
file:human/TOMM22/TOMM22-deep-research-falcon.md
1) a **major preprotein-binding site** and transfer platform, and
GO:0070585 protein localization to mitochondrion
TAS
PMID:14557246
AIP is a mitochondrial import mediator that binds to both im...
ACCEPT
Summary: Correct. TOMM22 is a central TOM-complex receptor/scaffold enabling localization/import of nuclear-encoded mitochondrial precursor proteins.
Supporting Evidence:
file:human/TOMM22/TOMM22-deep-research-falcon.md
The **TOM complex** is the primary entry gate for most nucleus-encoded mitochondrial proteins into mitochondria.
file:human/TOMM22/TOMM22-deep-research-falcon.md
TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.

Core Functions

TOMM22 is the central receptor/scaffold subunit of the mitochondrial outer membrane TOM complex, binding mitochondrial precursor proteins and transferring them toward the TOMM40 pore while stabilizing TOM complex assembly.

Supporting Evidence:
  • file:human/TOMM22/TOMM22-deep-research-falcon.md
    Human **TOMM22 (Q9NS69)** encodes **hTom22**, a **single-pass outer mitochondrial membrane** subunit of the TOM complex that acts as the **central receptor** and an **assembly-organizing scaffold**.
  • file:human/TOMM22/TOMM22-deep-research-falcon.md
    TOMM22 functions as a **major preprotein-binding site** and **organizational scaffold** for the TOM complex, helping recognize mitochondrial precursor proteins and transfer them toward the **Tom40 import pore**.
  • file:human/TOMM22/TOMM22-deep-research-falcon.md
    2) an **organizational scaffold** required for correct **TOM complex assembly** and stability.
  • file:human/TOMM22/TOMM22-deep-research-falcon.md
    hTom22 is an **outer mitochondrial membrane (OMM)** component and is structurally a **single-pass amphipathic Ξ±-helical** protein.

References

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Suggested Questions for Experts

Q: Which human mitochondrial precursor classes rely most directly on TOMM22 rather than TOMM20 or TOMM70 receptor engagement?

Q: How separable are TOMM22 precursor-receptor functions from its TOM complex assembly/stability role in human cells?

Suggested Experiments

Experiment: Use TOMM22 cytosolic-domain and transmembrane/interface mutants in rescue cells, then compare precursor binding, TOM complex assembly by BN-PAGE, and import of presequence versus internal-signal substrates.

Hypothesis: TOMM22 targeting-sequence binding and TOM complex scaffold functions are separable.

Experiment: Titrate TOMM22 expression in human cells and measure TOM assembly intermediates, Tom40/Tom7 incorporation, and import flux for representative matrix, inner-membrane, and outer-membrane substrates.

Hypothesis: TOMM22 abundance can become rate-limiting for TOM complex assembly and mitochondrial protein import in high-biogenesis contexts.

Deep Research

Falcon

(TOMM22-deep-research-falcon.md)

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