GOLGA7

GOLGA7 (GCP16) is a palmitoylated accessory subunit that partners with DHHC-family protein S-acyltransferases to control the palmitoylation and trafficking of Ras GTPases and other substrates (PMID:16000296, PMID:14522980). As a Golgi-localized membrane protein, GOLGA7 is itself palmitoylated at Cys69 and Cys72, a modification required for its Golgi membrane association, and its overexpression impedes Golgi-to-surface transport (PMID:14522980). It forms a stable, enzymatically active complex with DHHC9 (ZDHHC9) that constitutes an H-Ras/N-Ras palmitoyltransferase, with GOLGA7 required both for DHHC9 protein stability and for catalytic activity (PMID:16000296). Mechanistically GOLGA7 does not participate directly in catalysis; cryo-EM of the DHHC9-GCP16 and yeast Erf2-Erf4 complexes shows that it stabilizes the architecture of the DHHC enzyme (PMID:38182928), preventing DHHC9 aggregation through a conserved C-terminal cysteine motif of the DHHC9 subfamily (PMID:37035671), and stabilizing the catalytic palmitoyl-enzyme thioester intermediate by slowing its hydrolysis (PMID:22904317). Beyond DHHC9, GOLGA7 also stabilizes and activates DHHC14 and DHHC18 (PMID:37035671, PMID:38182928) and assembles a distinct, mutually stabilizing plasma-membrane complex with ZDHHC5 that drives CIL56-induced nonapoptotic cell death (PMID:31631010, PMID:40930250). Independently of its palmitoyltransferase role, GOLGA7 is required for anterograde trafficking of NRAS from the cis-Golgi to the plasma membrane without affecting NRAS palmitoylation levels, and its loss selectively impairs NRAS-mutant cancer proliferation and NRAS(G12D)-driven oncogenic transformation and myeloid leukemia in vivo while sparing normal adult hematopoiesis (PMID:38317235, PMID:40091521). GOLGA7 is also exploited as a host factor by SARS-CoV-2 and chikungunya virus entry/replication (PMID:34961524).

1. 2003 High

   Established GOLGA7/GCP16 as a Golgi membrane protein whose own palmitoylation governs its localization and whose presence influences secretory transport, defining its baseline cell biology before any enzymatic role was known.

   Evidence Yeast two-hybrid with GCP170, [3H]palmitate labeling, C69A/C72A mutagenesis, immunofluorescence and transport assay

   PMID:14522980

   Open questions at the time

   • Did not connect GCP16 to any DHHC enzyme or palmitoyltransferase activity
   • Mechanism of the Golgi transport inhibition unresolved
2. 2005 High

   Showed that GCP16 is an obligate partner of DHHC9, together forming the H-Ras/N-Ras palmitoyltransferase, answering how Ras becomes palmitoylated at the Golgi.

   Evidence Purified enzyme reconstitution with substrate-specificity assay, co-IP, subcellular fractionation/IF

   PMID:16000296

   Open questions at the time

   • Whether GCP16 contributes to catalysis or only to stability was not resolved
   • Structural basis of the interaction unknown
3. 2008 High

   Characterized the purified DHHC9/GCP16 enzyme pharmacologically, establishing that inhibitors act at the DHHC autoacylation step and exposing discrepancies between cell-based and purified-enzyme inhibitor selectivity.

   Evidence In vitro palmitoyltransferase assay with purified complex and inhibitor profiling (2-bromopalmitate, Compound V)

   PMID:18827284

   Open questions at the time

   • No GCP16-specific binding site for inhibitors defined
   • Cell-based selectivity discrepancy left mechanistically unexplained
4. 2012 High

   Defined the catalytic contribution of the accessory subunit: via the yeast ortholog Erf4, showed it stabilizes the palmitoyl-enzyme thioester intermediate and protects the enzyme through a ubiquitin-mediated stability pathway.

   Evidence Yeast genetics, in vitro palmitoylation assay, reaction-intermediate kinetics, ubiquitin pathway analysis

   PMID:22904317

   Open questions at the time

   • Extrapolated from yeast Erf4 rather than human GCP16 directly
   • Identity of the ubiquitin ligase not established
5. 2019 High

   Revealed a second, distinct GOLGA7 complex with ZDHHC5 at the plasma membrane that is required for CIL56-induced nonapoptotic cell death, broadening GOLGA7 beyond the Golgi DHHC9 axis.

   Evidence CRISPR KO, reciprocal co-IP, immunofluorescence, cell-death assays

   PMID:31631010

   Open questions at the time

   • Substrate(s) of the ZDHHC5-GOLGA7 complex driving cell death not identified
   • Mechanism linking palmitoylation to nonapoptotic death unresolved
6. 2020 Medium

   Synthesized prior work to position GCP16 as a general accessory regulator of DHHC enzyme activity, stability, and trafficking within the broader S-acylation system.

   Evidence Review synthesizing purified-component and cellular studies

   PMID:33203738

   Open questions at the time

   • No new primary data
   • Scope of GOLGA7-dependent DHHC enzymes not yet experimentally bounded
7. 2023 High

   Established the structural/biochemical basis of GCP16 selectivity, showing it stabilizes DHHC9 by preventing aggregation via a conserved C-terminal cysteine motif and extends activation to DHHC14 and DHHC18, while disease mutations in ZDHHC9 weaken complex formation.

   Evidence Size-exclusion chromatography, in vitro PAT assay, mutagenesis, co-expression stability assays

   PMID:37035671

   Open questions at the time

   • Did not provide atomic structure of the interface
   • GOLGA7B vs GOLGA7 paralog selectivity rules incompletely mapped
8. 2024 High

   Cryo-EM structures of human DHHC9-GCP16 and yeast Erf2-Erf4 resolved that the accessory subunit is non-catalytic and acts purely as an architectural stabilizer, while defining DHHC9 lipid binding and autopalmitoylation requirements.

   Evidence Cryo-EM structure determination, mutagenesis, in vitro palmitoylation assay, co-IP

   PMID:38182928

   Open questions at the time

   • Conformational dynamics during the catalytic cycle not captured
   • Structural basis for substrate (Ras) recognition not resolved
9. 2024 High

   Uncovered a palmitoylation-independent function: GOLGA7 is specifically required for NRAS anterograde transport from cis-Golgi to plasma membrane and for NRAS-mutant oncogenic phenotypes, separating its trafficking role from its enzyme-accessory role.

   Evidence siRNA/shRNA/CRISPR knockdown and KO, fluorescence localization, palmitoylation assay, in vivo mouse transformation

   PMID:38317235

   Open questions at the time

   • Molecular machinery linking GOLGA7 to NRAS-selective vesicular transport unknown
   • Why HRAS/KRAS are unaffected not explained
10. 2025 High

    Validated GOLGA7 as a therapeutic target in vivo: conditional knockout suppresses NRAS(G12D)-driven myeloid leukemia by disrupting NRAS plasma-membrane localization without affecting palmitoylation, while being dispensable for normal adult hematopoiesis.

    Evidence Conditional Cre-mediated knockout mouse leukemia model, flow cytometry, localization and palmitoylation assays

    PMID:40091521

    Open questions at the time

    • Embryonic lethality of constitutive knockout indicates essential roles not defined here
    • Whether the trafficking defect is direct or secondary remains open
11. 2025 High

    Resolved the ZDHHC5-GOLGA7 complex by cryo-EM and pinpointed interface residues required for both assembly and CIL56-induced cancer cell death, structurally completing the second GOLGA7 complex.

    Evidence Cryo-EM, co-IP, mutagenesis, functional cell-death assay

    PMID:40930250

    Open questions at the time

    • Substrate engaged by the complex during cell death not defined
    • Generalizability of interface residues to other DHHC-GOLGA7 pairs untested
12. 2026 Medium

    Demonstrated the ZDHHC9-GCP16 complex is druggable, identifying six small-molecule inhibitors with low-micromolar potency in a cell-based assay.

    Evidence Cell-based high-throughput palmitoylation assay (APT1 fusion), dose-response IC50 determination

    PMID:41850277

    Open questions at the time

    • Binding sites and selectivity of compounds not defined
    • Whether compounds act on GCP16, DHHC9, or the interface unknown
13. 2025 Medium

    Implicated GOLGA7 as a host dependency factor for viral infection, expanding its functional reach beyond Ras biology.

    Evidence Genome-wide CRISPR KO replicon screen with live chikungunya virus confirmation (preprint)

    Open questions at the time

    • Mechanism of GOLGA7 requirement in CHIKV replication unknown
    • Preprint, not yet peer-reviewed

• The molecular basis by which GOLGA7 selectively chaperones NRAS Golgi-to-membrane transport independently of palmitoylation, and how this connects to its DHHC-accessory function, remains unresolved.
• No identified trafficking machinery or adaptor linking GOLGA7 to NRAS vesicles
• Cause of constitutive-knockout embryonic lethality uncharacterized
• Substrates of ZDHHC5-GOLGA7 in cell death not identified