Single-pass type II membrane alpha/beta-hydrolase (271 aa) containing an N-terminal signal-anchor transmembrane helix (residues 35-55), predicted lumenal N-glycosylation sites at Asn67 and Asn201, and a conserved Ser171-Asp222-His249 charge-relay catalytic triad within a secretory-lumenal alpha/beta-hydrolase domain. Full-length human ABHD14A-GFP localizes to the Golgi apparatus upon expression in human HEK293T cells, and an engineered soluble N-terminally truncated human variant turns over synthetic short-chain p-nitrophenyl esters with coenzyme A-dependent enhancement in vitro, whereas its native physiological substrates and cellular biological process remain undetermined. Closely related in sequence to — yet topologically and compartmentally distinct from — its soluble cytosolic/nuclear lysine deacetylase paralog ABHD14B; its rodent ortholog Dorz1 is transcriptionally upregulated downstream of ZIC1 in differentiating embryonic cerebellar granule neuron precursors without an established protein-level phenotype.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005737 cytoplasm | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT phylogenetic inference of cytoplasmic localization from ancestral ABHD14 family node PANTHER:PTN002475422 seeded by mouse Abhd14a (MGI:1915894, PMID:14667578) and human ABHD14B (Q96IU4). Reason: Compatible with human ABHD14A's single-pass type II endomembrane/Golgi topology (residues 35-55 signal-anchor presenting its N-terminal tail to the cytoplasm) and orthologous mouse MGI:1915894 seed evidence on PTN002475422, while noting that the glycosylated C-terminal Ser171-Asp222-His249 catalytic domain is predicted to face the Golgi lumen rather than the cytosol. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN002475422 · PTN002475422 SUPPORTS TRANSFER Seeded by orthologous mouse Abhd14a (MGI:1915894, PMID:14667578) as well as paralogous soluble human ABHD14B (Q96IU4). Supporting Evidence: file:human/ABHD14A/ABHD14A-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250}. Membrane {ECO:0000305}; file:human/ABHD14A/ABHD14A-uniprot.txt Single-pass type II membrane protein {ECO:0000305}. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: Electronic mapping from UniProt Subcellular Location SL-0086 (Cytoplasm, ECO:0000250), reinforcing the independent PAINT IBA row. Reason: Accepted consistently with the PAINT IBA row on GO:0005737, with the standing topological caveat that human ABHD14A is a type II Golgi membrane protein (unlike soluble paralog ABHD14B) whose catalytic domain is predicted to face the secretory lumen. Supporting Evidence: file:human/ABHD14A/ABHD14A-uniprot.txt CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250}. Membrane {ECO:0000305}; file:human/ABHD14A/ABHD14A-uniprot.txt Single-pass type II membrane protein {ECO:0000305}. |
| GO:0016020 membrane | IEA GO_REF:0000044 | MODIFY | Summary: Generic UniProt Subcellular Location membrane mapping (SL-0162) from single-pass type II signal-anchor topology (residues 35-55); refined to GO:0000139 (Golgi membrane), which human ABHD14A already carries. Reason: Human ABHD14A carries an N-terminal type II signal-anchor transmembrane helix (residues 35-55), and full-length human ABHD14A-GFP localizes specifically to the Golgi apparatus in human HEK293T cells (PMID:42469586); generic GO:0016020 (membrane) is therefore refined to the supported descendant GO:0000139 (Golgi membrane) already asserted on Q9BUJ0. Proposed replacements: Golgi membrane Supporting Evidence: file:human/ABHD14A/ABHD14A-uniprot.txt FT /note="Helical; Signal-anchor for type II membrane protein" PMID:42469586 Here, we found that the ABHD14A-GFP fusion protein is catalytically active and localizes specifically to the Golgi apparatus, suggesting a specialized role in the secretory pathway biology. |
| GO:0000139 Golgi membrane | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Golgi membrane localization supported by heterologous human ABHD14A-GFP imaging in HEK293T cells (PMID:42469586) and human ABHD14A's predicted type II signal-anchor helix (residues 35-55) and lumenal N-glycosylation sites (Asn67, Asn201), routed in GOA as ISS via rat Q5I0C4. Reason: PMID:42469586 demonstrates that catalytically active human ABHD14A-GFP localizes specifically to the Golgi apparatus in HEK293T cells, matching the conserved type II signal-anchor topology. Kept as non-core rather than core because localization rests on heterologous GFP-fusion overexpression without endogenous human protein detection and the native Golgi biological function remains unknown; also flagged with a PROBABLE CHECK source defect because UniProt entered the PMID:42469586 Golgi IDA on rat Q5I0C4 and projected ISS back to human Q9BUJ0. Supporting Evidence: PMID:42469586 Here, we found that the ABHD14A-GFP fusion protein is catalytically active and localizes specifically to the Golgi apparatus, suggesting a specialized role in the secretory pathway biology. file:human/ABHD14A/ABHD14A-uniprot.txt FT /note="Helical; Signal-anchor for type II membrane protein" |
| GO:0016407 acetyltransferase activity | IDA PMID:42469586 Biochemical Characterization of ABHD14A, an Outlying Member ... | MARK AS OVER ANNOTATED | Summary: In vitro coenzyme A-enhanced turnover of synthetic short-chain p-nitrophenyl acetate by an engineered soluble N-terminally truncated human ABHD14A construct (PMID:42469586). Reason: Gupta, Dhaware & Kamat 2026 (PMID:42469586) demonstrated real in vitro esterase/CoA-enhanced acetyl-transfer activity using an N-terminally truncated soluble construct and artificial chromogenic p-nitrophenyl esters while explicitly stating that physiological substrates remain to be discovered; per the enzyme-specificity policy, real in vitro activity on surrogate substrates of unknown physiological relevance is marked as over-annotated consistently with mouse and rat Abhd14a. Supporting Evidence: PMID:42469586 Notably, ABHD14A exhibits a coenzyme A-dependent enhancement of p-nitrophenyl acetate hydrolysis, indicative of a ping-pong type acetyltransferase mechanism similar to that previously described for another homologous ABHD14 enzyme, ABHD14B. PMID:42469586 Together, these findings establish the enzymatic activity, mechanistic features, and subcellular localization of ABHD14A while providing essential biochemical tools that can now enable the systematic discovery of its physiological substrates and regulatory contexts. |
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Download this section (compressed HTML)Q: Which side of the Golgi membrane does the Ser171-Asp222-His249 catalytic domain of endogenous human ABHD14A face, and if it is lumenal (as predicted by the residues 35-55 type II signal-anchor and Asn67/Asn201 glycosylation sites), what lumenal acyl donor and acceptor replace cytosolic CoA in vivo?
Q: Which physiological initiator methionine (Met1 vs Met30, both upstream of the residues 35-55 signal-anchor) is translated in endogenous human neural and secretory tissues?
Q: Did PMID:42469586 assay only human ABHD14A-GFP for Golgi localization (in which case UniProt's GO:0000139 IDA on rat Q5I0C4 and ISS back to Q9BUJ0 should be inverted)?
Experiment: Perform PNGase F / Endo H deglycosylation and proteinase K protection assays on Golgi-enriched microsomes expressing WT vs S171A human ABHD14A, followed by comparative untargeted LC-MS/MS metabolomics, lipidomics, and acylome profiling.
Hypothesis: Full-length human ABHD14A is a lumenally oriented type II Golgi membrane enzyme that modifies a secretory-pathway lipid, metabolite, or glycoprotein substrate distinct from cytosolic/nuclear ABHD14B targets.
Type: topology assay and untargeted mass spectrometry
Experiment: Generate a paralog-specific monoclonal antibody or endogenous epitope knock-in validated against ABHD14B cross-reactivity (using sequence determinants from PMID:37974539) and profile human iPSC-derived neural progenitors and developing mouse cerebellum.
Hypothesis: Endogenous ABHD14A protein expression is developmentally restricted to specific neural or secretory cell populations such as differentiating cerebellar granule neuron precursors.
Type: expression and localization analysis
What is not known — curated, literature-grounded statements of the open unknowns (the inverse of core functions).
Gap: The endogenous physiological acyl donor and acceptor substrates of human Golgi-localized type II membrane enzyme ABHD14A are unknown, and whether coenzyme A or another lumenal thiol/protein acceptor serves as cosubstrate for its predicted lumenal catalytic domain in vivo is unresolved.
NARROWING BIOLOGY MF_DARK
What is known: Human ABHD14A (Q9BUJ0) retains a complete Ser171-Asp222-His249 catalytic triad and N-terminal type II signal-anchor (residues 35-55; note UniProt also flags uncertainty between Met1 and Met30 initiation), and an engineered soluble N-terminally truncated human construct turns over short-chain p-nitrophenyl esters with CoA enhancement in vitro while full-length ABHD14A-GFP localizes to the Golgi apparatus in HEK293T cells (PMID:42469586).
Significance: Prevents premature assignment of a specific physiological molecular function from surrogate p-nitrophenyl acetate assays and guards against paralog conflation with cytosolic/nuclear KDAC ABHD14B (PMID:37974539).
What would resolve it: Perform untargeted lipidomic, glycoproteomic, and acyl-acceptor profiling on Golgi membranes from wild-type vs catalytic-dead S171A human ABHD14A cells, combined with protease-protection/glycosylation topology mapping of the catalytic domain.
Provenance (the field's own admissions):
Gap: No physiological biological process or loss-of-function cellular/organismal phenotype has been established for human ABHD14A.
OPEN BIOLOGY BP_DARK
What is known: UniProt's ECO:0000250 comment ('Possible role in granule neuron development') derives solely from Zic1-dependent mRNA expression of rodent Dorz1 in embryonic cerebellar granule neuron precursors (PMID:14667578), and Golgi localization of ABHD14A-GFP in HEK293T cells (PMID:42469586) has not yet been linked to a specific secretory-pathway process.
Significance: Separates regulated neuronal transcript expression and heterologous Golgi localization from demonstrated participation in a biological process.
What would resolve it: Assess secretory-pathway glycoprotein/lipid processing and neuronal differentiation phenotypes in human iPSC-derived cerebellar/secretory cells or Abhd14a knockout mice rescued with WT vs S171A ABHD14A.
Provenance (the field's own admissions):
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