COQ5

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0006744 ubiquinone biosynthetic process	IBA GO_REF:0000033	ACCEPT	Summary: Core biological process. COQ5 performs the only C-methylation of the ubiquinone head group and is a conserved member of the COQ family; the phylogenetic (IBA) inference to ubiquinone biosynthesis is well supported and concordant with direct experimental evidence. Supporting Evidence: PMID:25152161 catalyzes the only C-methylation involved in the biosynthesis of coenzyme Q
GO:0008425 2-methoxy-6-polyprenyl-1,4-benzoquinol methyltransferase activity	IBA GO_REF:0000033	ACCEPT	Summary: Core molecular function; the exact, specific activity of COQ5. The phylogenetic inference matches the enzyme's demonstrated C-methyltransferase activity in the ubiquinone pathway. Supporting Evidence: PMID:25152161 catalyzes the only C-methylation involved in the biosynthesis of coenzyme Q
GO:0005743 mitochondrial inner membrane	IEA GO_REF:0000044	ACCEPT	Summary: Correct localization. COQ5 is a peripheral (extrinsic) inner-membrane protein on the matrix side; the SubCell-based electronic annotation is consistent with experimental IDA/EXP evidence. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0006744 ubiquinone biosynthetic process	IEA GO_REF:0000120	ACCEPT	Summary: Correct core BP by electronic pipeline (UniRule/UniPathway UPA00232); redundant with experimental and phylogenetic annotations to the same term. Supporting Evidence: PMID:38425362 C2 methylation of 4b by COQ5
GO:0008168 methyltransferase activity	IEA GO_REF:0000002	MARK AS OVER ANNOTATED	Summary: Correct but generic. GO:0008168 is a broad parent of the specific activity GO:0008425 that is already annotated; the specific term should be preferred, so this general term is an over-annotation. Reason: Parent (generic methyltransferase activity) of the specific and experimentally supported GO:0008425.
GO:0008425 2-methoxy-6-polyprenyl-1,4-benzoquinol methyltransferase activity	IEA GO_REF:0000120	ACCEPT	Summary: Core molecular function assigned electronically from RHEA:44764 / EC:2.1.1.201, matching the UniProt catalytic activity; redundant with the experimental IDA annotations to the same term. Supporting Evidence: PMID:38425362 C2 methylation of 4b by COQ5
GO:0031314 extrinsic component of mitochondrial inner membrane	IEA GO_REF:0000104	ACCEPT	Summary: Accurate and informative CC. COQ5 is a peripheral membrane protein bound to the matrix face of the inner membrane, matching "extrinsic component of mitochondrial inner membrane". Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005515 protein binding	IPI PMID:27499296 Mitochondrial Protein Interaction Mapping Identifies Regulat...	MARK AS OVER ANNOTATED	Summary: Bona fide binary interaction with COQ9 (O75208), a COQ synthome partner, but "protein binding" is uninformative. The interaction is better captured by the ubiquinone biosynthesis complex (COQ synthome) part_of annotation. Reason: Uninformative generic GO:0005515; the biology (COQ synthome membership) is captured by GO:0110142.
GO:0006744 ubiquinone biosynthetic process	TAS Reactome:R-HSA-2142789	ACCEPT	Summary: Correct core BP asserted by Reactome (Ubiquinol biosynthesis); redundant with experimental evidence but accurately captures COQ5's role. Supporting Evidence: PMID:38425362 C2 methylation of 4b by COQ5
GO:0008425 2-methoxy-6-polyprenyl-1,4-benzoquinol methyltransferase activity	TAS Reactome:R-HSA-2162188	ACCEPT	Summary: Correct core MF asserted by Reactome for the COQ5-catalyzed methylation reaction (R-HSA-2162188 "COQ5 methylates MDMQ10H2"); consistent with the experimental IDA annotations. Supporting Evidence: PMID:38425362 C2 methylation of 4b by COQ5
GO:0005743 mitochondrial inner membrane	IDA PMID:27499296 Mitochondrial Protein Interaction Mapping Identifies Regulat...	ACCEPT	Summary: Experimental (ComplexPortal IDA) localization of COQ5 to the mitochondrial inner membrane, consistent with its role as a matrix-side peripheral inner-membrane protein and COQ synthome component. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0006744 ubiquinone biosynthetic process	NAS PMID:28927698 Biochemistry of Mitochondrial Coenzyme Q Biosynthesis.	ACCEPT	Summary: Correct core BP asserted (NAS) in a review of mitochondrial coenzyme Q biosynthesis; redundant with experimental evidence but accurate. Supporting Evidence: PMID:38425362 C2 methylation of 4b by COQ5
GO:0110142 ubiquinone biosynthesis complex	IPI PMID:27499296 Mitochondrial Protein Interaction Mapping Identifies Regulat...	ACCEPT	Summary: Core cellular component. COQ5 is a subunit of the multi-subunit COQ enzyme complex (CoQ synthome / COQ metabolon) with COQ3, COQ4, COQ6, COQ7 and COQ9; this part_of annotation precisely captures that membership. Supporting Evidence: PMID:25152161 assemble with the multi-subunit complex termed the CoQ-synthome PMID:38425362 These include COQ3, COQ4, COQ5, COQ6, COQ7 and COQ9
GO:0005739 mitochondrion	IDA GO_REF:0000052	KEEP AS NON CORE	Summary: Correct but least specific localization (HPA immunofluorescence IDA). The specific matrix / inner-membrane locations are more informative. Reason: Parent compartment of the specific mitochondrial matrix / inner-membrane annotations.
GO:0005759 mitochondrial matrix	TAS Reactome:R-HSA-2162186	ACCEPT	Summary: Correct matrix-side localization asserted by Reactome; this Reactome reaction is the COQ3 step but Reactome co-annotates all COQ synthome members to the mitochondrial matrix. Concordant with the experimental IDA matrix annotation. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005759 mitochondrial matrix	TAS Reactome:R-HSA-2162187	ACCEPT	Summary: Correct matrix-side localization asserted by Reactome (COQ6 reaction step, co-annotated to the synthome). Concordant with the experimental IDA matrix annotation. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005759 mitochondrial matrix	TAS Reactome:R-HSA-2162188	ACCEPT	Summary: Correct matrix-side localization asserted by Reactome for the COQ5 methylation reaction step (R-HSA-2162188). Concordant with the experimental IDA matrix annotation. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005759 mitochondrial matrix	TAS Reactome:R-HSA-2162193	ACCEPT	Summary: Correct matrix-side localization asserted by Reactome (COQ3 reaction step, co-annotated to the synthome). Concordant with the experimental IDA matrix annotation. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005759 mitochondrial matrix	TAS Reactome:R-HSA-2162194	ACCEPT	Summary: Correct matrix-side localization asserted by Reactome (COQ7:COQ9 reaction step, co-annotated to the synthome). Concordant with the experimental IDA matrix annotation. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005759 mitochondrial matrix	TAS Reactome:R-HSA-2162195	ACCEPT	Summary: Correct matrix-side localization asserted by Reactome (COQ4 reaction step, co-annotated to the synthome). Concordant with the experimental IDA matrix annotation. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005743 mitochondrial inner membrane	EXP PMID:35614220 Defining mitochondrial protein functions through deep multio...	ACCEPT	Summary: Experimental localization of COQ5 to the mitochondrial inner membrane (deep multiomic profiling study that also defined the direct PYURF-COQ5 interaction). Consistent with the matrix-side peripheral inner-membrane localization. Supporting Evidence: file:human/COQ5/COQ5-uniprot.txt Mitochondrion inner membrane
GO:0006744 ubiquinone biosynthetic process	IDA PMID:38425362 In vitro construction of the COQ metabolon unveils the molec...	ACCEPT	Summary: Direct experimental support for the core BP. In vitro reconstruction of the COQ metabolon showed COQ5 performs the C2 methylation step of the ubiquinone head-group biosynthetic pathway. Supporting Evidence: PMID:38425362 COQ5 was incubated overnight at 30 °C with SAM and its substrate, 4b; GC/MS analysis confirmed enzymatic activity and production of 5
GO:0008425 2-methoxy-6-polyprenyl-1,4-benzoquinol methyltransferase activity	IDA PMID:38425362 In vitro construction of the COQ metabolon unveils the molec...	ACCEPT	Summary: Direct experimental demonstration of the core molecular function. Purified COQ5 catalyzed SAM-dependent C2 methylation of the benzoquinol substrate with Michaelis-Menten kinetics (kcat 2.4 min-1, KM 444 uM). Supporting Evidence: PMID:38425362 COQ5 showed typical Michaelis−Menten kinetics over titration of 4b
GO:0005739 mitochondrion	HTP PMID:34800366 Quantitative high-confidence human mitochondrial proteome an...	KEEP AS NON CORE	Summary: High-throughput mitochondrial proteome study places COQ5 in the mitochondrion; correct but least specific compartment. Reason: Parent compartment of the specific matrix / inner-membrane annotations.
GO:0005515 protein binding	IPI PMID:35614220 Defining mitochondrial protein functions through deep multio...	MARK AS OVER ANNOTATED	Summary: Direct interaction with PYURF (Q96I23), which stabilizes COQ5 and links PYURF to the COQ enzyme complex. A real and biologically important interaction, but the generic "protein binding" term is uninformative. Reason: Uninformative generic GO:0005515; the PYURF interaction is documented in the description and SUBUNIT notes.
GO:0005515 protein binding	IPI PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	MARK AS OVER ANNOTATED	Summary: Bona fide interaction with COQ4 (Q9Y3A0) demonstrated by reciprocal co-immunoprecipitation in human cells, but "protein binding" is uninformative; membership in the COQ synthome is captured by GO:0110142. Reason: Uninformative generic GO:0005515; the COQ4 interaction reflects COQ synthome membership (GO:0110142). Supporting Evidence: PMID:25152161 immune-precipitation of COQ4-V5 captures COQ5-myc and vice versa
GO:0005743 mitochondrial inner membrane	IDA PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	ACCEPT	Summary: Experimental colocalization of COQ5 with the mitochondrial inner membrane; consistent with its matrix-side peripheral inner-membrane localization. The colocalizes_with qualifier appropriately reflects that it is a peripheral, not integral, membrane protein. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0005759 mitochondrial matrix	IDA PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	ACCEPT	Summary: Core cellular component supported by direct experimental evidence. COQ5 is a peripheral inner-membrane protein exposed on the matrix side, consistent with mitochondrial matrix localization. Supporting Evidence: PMID:25152161 associated with the mitochondrial inner membrane on the matrix side
GO:0006744 ubiquinone biosynthetic process	IGI PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	ACCEPT	Summary: Genetic-interaction (yeast complementation) evidence for the core BP. Human COQ5 partially rescued yeast coq5 mutants for respiratory growth and Q6 content, demonstrating a conserved role in ubiquinone biosynthesis. Supporting Evidence: PMID:25152161 catalyzes the only C-methylation involved in the biosynthesis of coenzyme Q
GO:0008425 2-methoxy-6-polyprenyl-1,4-benzoquinol methyltransferase activity	IDA PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	ACCEPT	Summary: Direct experimental support for the core molecular function; COQ5 is the C-methyltransferase catalyzing the sole C-methylation of the coenzyme Q head group. Supporting Evidence: PMID:25152161 catalyzes the only C-methylation involved in the biosynthesis of coenzyme Q
GO:0032259 methylation	IDA PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	MARK AS OVER ANNOTATED	Summary: "Methylation" is a generic BP grouping term. The specific molecular function (GO:0008425) and specific biological process (GO:0006744) already capture the methyltransferase role, making this general term redundant. Reason: Generic process term subsumed by the specific MF (GO:0008425) and BP (GO:0006744) annotations.
GO:0032991 protein-containing complex	IDA PMID:25152161 Molecular characterization of the human COQ5 C-methyltransfe...	MARK AS OVER ANNOTATED	Summary: Correct but generic. COQ5 is part of the COQ synthome, but the specific complex term GO:0110142 (ubiquinone biosynthesis complex) is already annotated and is far more informative. Reason: Parent of the specific GO:0110142 ubiquinone biosynthesis complex.

Gene Description

Existing Annotations Review

Core Functions

2-methoxy-6-polyprenyl-1,4-benzoquinol C-methyltransferase: catalyzes the sole C-methylation of the coenzyme Q head group, transferring a methyl group from S-adenosyl-L-methionine to the C2 position of the polyprenylated benzoquinol ring and producing S-adenosyl-L-homocysteine.

References

📚 Additional Documentation

Notes

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