PMPCA encodes the alpha subunit of the mitochondrial processing peptidase (MPP), a matrix heterodimer with PMPCB that removes N-terminal mitochondrial targeting presequences from imported precursor proteins. PMPCA is the substrate-recognition/binding subunit, including a glycine-rich loop that helps position precursor proteins for cleavage by the catalytic PMPCB beta subunit; it is essential for productive MPP activity but is not itself the catalytic metalloprotease.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0017087 mitochondrial processing peptidase complex | IBA GO_REF:0000033 | ACCEPT | Summary: PMPCA is a defining alpha subunit of the heterodimeric mitochondrial processing peptidase complex with PMPCB. Reason: The annotation captures the core complex membership of PMPCA in MPP. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0004222 metalloendopeptidase activity | IEA GO_REF:0000002 | MODIFY | Summary: The MPP complex has Zn2+-dependent metalloendopeptidase activity, but the catalytic site is in PMPCB; PMPCA contributes substrate recognition and positioning. Reason: As an enabled molecular function on PMPCA alone, metalloendopeptidase activity overstates the alpha subunit. Replace the direct enabled MF with protein-macromolecule adaptor activity and represent complex protease activity as contributes_to in core_functions. Proposed replacements: protein-macromolecule adaptor activity Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **Zn2+-dependent metallopeptidase**. The catalytic model described for MPP cleavage is thermolysin-like, in which a **Zn2+-bound water** (polarized by a catalytic glutamate) performs nucleophilic attack on the scissile peptide bond; the **Zn2+-binding motif** resides in PMPCB/MPPĪ² (HxxEHā¦E) (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). PMPCA is therefore **catalytically inactive** in the metalloprotease sense but essential for productive substrate engagement (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, joshi2016mutationsinthe pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005743 mitochondrial inner membrane | IEA GO_REF:0000044 | MODIFY | Summary: PMPCA/MPP acts in the mitochondrial matrix after precursor import rather than being an inner-membrane component. Reason: The more precise supported cellular component for PMPCA is mitochondrial matrix. Proposed replacements: mitochondrial matrix Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005759 mitochondrial matrix | IEA GO_REF:0000120 | ACCEPT | Summary: MPP acts in the mitochondrial matrix where imported precursor proteins are processed. Reason: Matrix localization is directly consistent with the synthesized literature and Reactome annotations for MPP processing events. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0006508 proteolysis | IEA GO_REF:0000002 | MODIFY | Summary: PMPCA contributes to proteolytic removal of mitochondrial targeting presequences as part of MPP, but generic proteolysis is less informative than protein processing. Reason: Use protein processing to capture the maturation of imported mitochondrial precursor proteins rather than broad proteolysis. Proposed replacements: protein processing Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0016485 protein processing | IEA GO_REF:0000117 | ACCEPT | Summary: PMPCA contributes to MPP-dependent maturation of imported mitochondrial precursor proteins by presequence cleavage. Reason: Protein processing is the appropriate biological process for MPP-dependent precursor maturation. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0046872 metal ion binding | IEA GO_REF:0000002 | REMOVE | Summary: The catalytic zinc-binding motif of MPP resides in PMPCB/MPP beta, not PMPCA. Reason: The available evidence does not support metal ion binding as a direct PMPCA activity; this appears to be propagated from the complex/beta subunit metalloprotease mechanism. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **Zn2+-dependent metallopeptidase**. The catalytic model described for MPP cleavage is thermolysin-like, in which a **Zn2+-bound water** (polarized by a catalytic glutamate) performs nucleophilic attack on the scissile peptide bond; the **Zn2+-binding motif** resides in PMPCB/MPPĪ² (HxxEHā¦E) (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). PMPCA is therefore **catalytically inactive** in the metalloprotease sense but essential for productive substrate engagement (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, joshi2016mutationsinthe pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005515 protein binding | IPI PMID:30021884 Histone Interaction Landscapes Visualized by Crosslinking Ma... | MARK AS OVER ANNOTATED | Summary: Generic protein binding is uninformative for PMPCA. The biologically meaningful interaction is substrate recognition/positioning within the MPP complex. Reason: The annotation should be replaced in curation practice by specific MPP complex membership and the substrate-recognition/adaptor role, rather than retained as broad protein binding. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP recognizes presequences that are typically **positively charged amphipathic Ī±-helices**; reviews emphasize a frequent preference for **arginine at ā2 or ā3** relative to the cleavage site (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). PMPCAās **glycine-rich loop** is described as critical for substrate binding and/or guiding the precursor toward the catalytic center (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | MARK AS OVER ANNOTATED | Summary: Generic protein binding is uninformative for PMPCA. The biologically meaningful interaction is substrate recognition/positioning within the MPP complex. Reason: The annotation should be replaced in curation practice by specific MPP complex membership and the substrate-recognition/adaptor role, rather than retained as broad protein binding. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP recognizes presequences that are typically **positively charged amphipathic Ī±-helices**; reviews emphasize a frequent preference for **arginine at ā2 or ā3** relative to the cleavage site (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). PMPCAās **glycine-rich loop** is described as critical for substrate binding and/or guiding the precursor toward the catalytic center (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | MARK AS OVER ANNOTATED | Summary: Generic protein binding is uninformative for PMPCA. The biologically meaningful interaction is substrate recognition/positioning within the MPP complex. Reason: The annotation should be replaced in curation practice by specific MPP complex membership and the substrate-recognition/adaptor role, rather than retained as broad protein binding. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP recognizes presequences that are typically **positively charged amphipathic Ī±-helices**; reviews emphasize a frequent preference for **arginine at ā2 or ā3** relative to the cleavage site (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). PMPCAās **glycine-rich loop** is described as critical for substrate binding and/or guiding the precursor toward the catalytic center (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). |
| GO:0005739 mitochondrion | NAS PMID:32443488 Mitochondrial Protein Quality Control Mechanisms. | MODIFY | Summary: PMPCA is mitochondrial, but the evidence supports the more specific mitochondrial matrix localization of the MPP machinery. Reason: Use mitochondrial matrix rather than the broad parent term mitochondrion. Proposed replacements: mitochondrial matrix Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0017087 mitochondrial processing peptidase complex | NAS PMID:32443488 Mitochondrial Protein Quality Control Mechanisms. | ACCEPT | Summary: PMPCA is a defining alpha subunit of the heterodimeric mitochondrial processing peptidase complex with PMPCB. Reason: The annotation captures the core complex membership of PMPCA in MPP. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0070585 protein localization to mitochondrion | NAS PMID:32443488 Mitochondrial Protein Quality Control Mechanisms. | MARK AS OVER ANNOTATED | Summary: MPP processing is coupled to import for some substrates, but PMPCA acts after import by cleaving targeting presequences rather than serving as the localization/import machinery. Reason: The core process is mitochondrial precursor protein processing, not general protein localization to mitochondrion. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005739 mitochondrion | IDA GO_REF:0000052 | MODIFY | Summary: PMPCA is mitochondrial, but the evidence supports the more specific mitochondrial matrix localization of the MPP machinery. Reason: Use mitochondrial matrix rather than the broad parent term mitochondrion. Proposed replacements: mitochondrial matrix Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0016485 protein processing | IDA PMID:22354088 Mitochondrial processing peptidase regulates PINK1 processin... | ACCEPT | Summary: PMPCA contributes to MPP-dependent maturation of imported mitochondrial precursor proteins by presequence cleavage. Reason: Protein processing is the appropriate biological process for MPP-dependent precursor maturation. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0016485 protein processing | IMP PMID:25808372 PMPCA mutations cause abnormal mitochondrial protein process... | ACCEPT | Summary: PMPCA contributes to MPP-dependent maturation of imported mitochondrial precursor proteins by presequence cleavage. Reason: Protein processing is the appropriate biological process for MPP-dependent precursor maturation. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005739 mitochondrion | HTP PMID:34800366 Quantitative high-confidence human mitochondrial proteome an... | MODIFY | Summary: PMPCA is mitochondrial, but the evidence supports the more specific mitochondrial matrix localization of the MPP machinery. Reason: Use mitochondrial matrix rather than the broad parent term mitochondrion. Proposed replacements: mitochondrial matrix Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005759 mitochondrial matrix | ISS GO_REF:0000024 | ACCEPT | Summary: MPP acts in the mitochondrial matrix where imported precursor proteins are processed. Reason: Matrix localization is directly consistent with the synthesized literature and Reactome annotations for MPP processing events. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005759 mitochondrial matrix | TAS Reactome:R-HSA-8949649 | ACCEPT | Summary: MPP acts in the mitochondrial matrix where imported precursor proteins are processed. Reason: Matrix localization is directly consistent with the synthesized literature and Reactome annotations for MPP processing events. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005759 mitochondrial matrix | TAS Reactome:R-HSA-9838081 | ACCEPT | Summary: MPP acts in the mitochondrial matrix where imported precursor proteins are processed. Reason: Matrix localization is directly consistent with the synthesized literature and Reactome annotations for MPP processing events. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005759 mitochondrial matrix | TAS Reactome:R-HSA-9838093 | ACCEPT | Summary: MPP acts in the mitochondrial matrix where imported precursor proteins are processed. Reason: Matrix localization is directly consistent with the synthesized literature and Reactome annotations for MPP processing events. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005743 mitochondrial inner membrane | IDA PMID:25808372 PMPCA mutations cause abnormal mitochondrial protein process... | MODIFY | Summary: PMPCA/MPP acts in the mitochondrial matrix after precursor import rather than being an inner-membrane component. Reason: The more precise supported cellular component for PMPCA is mitochondrial matrix. Proposed replacements: mitochondrial matrix Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005576 extracellular region | HDA PMID:22664934 Comparison of tear protein levels in breast cancer patients ... | REMOVE | Summary: PMPCA is a mitochondrial matrix MPP subunit; the extracellular-region annotation is inconsistent with the curated functional literature. Reason: This high-throughput extracellular annotation is not supported by the gene-specific evidence and conflicts with the mitochondrial matrix role. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0005739 mitochondrion | IDA GO_REF:0000054 | MODIFY | Summary: PMPCA is mitochondrial, but the evidence supports the more specific mitochondrial matrix localization of the MPP machinery. Reason: Use mitochondrial matrix rather than the broad parent term mitochondrion. Proposed replacements: mitochondrial matrix Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md | Localization | MPP acts in the **mitochondrial matrix** after precursor import; human studies describe PMPCA/PMPCB as matrix-localized machinery that cleaves imported presequences, and impaired function leads to accumulation of **matrix precursors**. | Joshi 2016; KĆ¼cĆ¼kkƶse 2021 (joshi2016mutationsinthe pages 1-2, kucukkose2021functionalcouplingof pages 1-2) | file:human/PMPCA/PMPCA-deep-research-falcon.md **Primary function:** PMPCA, as part of MPP, enables **proteolytic cleavage of N-terminal mitochondrial targeting presequences** from imported precursor proteins, generating mature proteins competent for folding and assembly (kucukkose2021functionalcouplingof pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). MPP is described as the **primary** presequence-processing enzyme for the majority of presequence-containing mitochondrial proteins (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4, jobling2015pmpcamutationscause pages 1-2). |
| GO:0030674 protein-macromolecule adaptor activity | NAS file:human/PMPCA/PMPCA-deep-research-falcon.md | NEW | Summary: PMPCA has a substrate-recognition/positioning role within the MPP heterodimer, guiding precursor proteins toward the PMPCB catalytic site. Reason: This is the best available MF-level representation of the alpha subunit role distinct from PMPCB catalytic metalloendopeptidase activity. Supporting Evidence: file:human/PMPCA/PMPCA-deep-research-falcon.md MPP is a **heterodimer** of **PMPCA (Ī± subunit)** and **PMPCB (Ī² subunit)**. PMPCB provides the **Zn2+-dependent catalytic site**, while PMPCA provides **substrate recognition/binding**, including a conserved **glycine-rich loop** required for substrate handling (joshi2016mutationsinthe pages 1-2, kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). This division of labor is clinically important: pathogenic variants in PMPCA can disrupt substrate recognition and thereby impair processing of specific client proteins and broader mitochondrial biogenesis (joshi2016mutationsinthe pages 1-2, jobling2015pmpcamutationscause pages 1-2). file:human/PMPCA/PMPCA-deep-research-falcon.md MPP recognizes presequences that are typically **positively charged amphipathic Ī±-helices**; reviews emphasize a frequent preference for **arginine at ā2 or ā3** relative to the cleavage site (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). PMPCAās **glycine-rich loop** is described as critical for substrate binding and/or guiding the precursor toward the catalytic center (kunova2022mitochondrialprocessingpeptidasesāstructure pages 2-4). |
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Download this section (compressed HTML)Q: Would GO benefit from a term for mitochondrial presequence-recognition activity or MPP alpha-subunit substrate-guiding activity, distinct from generic adaptor activity and from PMPCB catalytic metalloendopeptidase activity?
Experiment: Reconstitute human PMPCA/PMPCB MPP variants with precursor substrates and measure substrate binding, positioning, and cleavage kinetics for PMPCA glycine-loop and patient alleles.
Hypothesis: PMPCA variants primarily impair precursor recognition/positioning while PMPCB provides the catalytic metallopeptidase chemistry.
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