GNA14

GNA14 encodes a Gαq-family heterotrimeric G protein subunit that couples receptor signaling to growth-controlling pathways, and which becomes oncogenic through a somatic activating mutation. The recurrent c.614A>T (p.Gln205Leu) substitution upregulates MAPK signaling in primary endothelial cells and melanocytes, conferring growth-factor independence and altered morphology (PMID:27476652), and in vivo drives MAPK and angiogenesis-related transcriptional programs to produce enlarged vessels in xenografts (PMID:38917801), consistent with a role in vascular tumor formation. In non-vascular epithelial cancers, GNA14 acts as a pro-proliferative effector: it promotes colorectal cancer growth through ERK phosphorylation and β-catenin phosphorylation at S675, and Gna14 loss reduces intestinal polyp burden in APC mice (PMID:37760541), while in endometrial carcinoma it engages a KLF7→HAS2 cascade to drive proliferation, migration, and xenograft growth (PMID:33892667). Conversely, in hepatocellular carcinoma GNA14 is tumor-suppressive, directly binding RACK1 to compete with PKC and thereby dampen MAPK/JNK and PI3K/AKT signaling (PMID:34657150), and promoting Notch1 cleavage to activate the RB pathway while suppressing JMJD6-driven metastasis; its expression in this context is silenced by HBx-induced promoter methylation (PMID:33500727). This context-dependent oncogene/tumor-suppressor duality is the central feature of GNA14 biology in the available corpus.

1. 2013 Low

   Established that Gna14 is a downstream transcriptional target of inflammatory signaling and contributes to tumor-initiating properties, linking it to cancer before its mutational role was known.

   Evidence Microarray-guided identification plus colony formation assay in a TNF-α/TNFR1 knockout × Gan gastric cancer mouse model

   PMID:23975421

   Open questions at the time

   • Colony formation as the primary functional readout; no pathway mechanism placed for Gna14 specifically
   • Does not establish whether the effect is via G-protein signaling
2. 2014 Low

   Addressed where GNA14 protein resides, finding both nuclear and cytoplasmic localization in vascular cell types.

   Evidence Immunocytochemistry, confocal microscopy, and bioinformatic NLS prediction in HPAECs and HPASMCs

   PMID:24797109

   Open questions at the time

   • No functional consequence tied to nuclear localization
   • Single study, no validation of the predicted NLS
3. 2016 Medium

   Identified the somatic gain-of-function p.Gln205Leu mutation as the driver of constitutive MAPK activation, defining GNA14 as an oncogene in vascular/melanocytic lineages.

   Evidence Expression of mutant GNA14 in primary human endothelial cells and melanocytes with MAPK, morphology, and growth-factor independence readouts

   PMID:27476652

   Open questions at the time

   • Single lab cell-based assay; no in vivo tumor formation in this study
   • Effector mechanism downstream of Gαq not dissected
4. 2018 Low

   Demonstrated a pro-proliferative, anti-apoptotic role for GNA14 in endometrial carcinoma, supporting an oncogenic function in this epithelial context.

   Evidence Lentiviral knockdown with caspase 3/7, apoptosis array, and cell cycle analysis

   PMID:30054423

   Open questions at the time

   • Limited mechanistic placement beyond caspase-3/Fas and G2/M arrest
   • No upstream signaling pathway defined
5. 2021 Medium

   Resolved a downstream transcriptional cascade for the oncogenic role in endometrial cancer, placing GNA14 upstream of a KLF7→HAS2 axis.

   Evidence Lentiviral knockdown/overexpression, RNA-seq, qRT-PCR, proliferation/migration assays, and xenograft model

   PMID:33892667

   Open questions at the time

   • Mechanism linking GNA14 G-protein activity to KLF7 induction not defined
   • Single lab
6. 2021 Medium

   Revealed a tumor-suppressive mechanism in a different tissue, showing GNA14 directly binds RACK1 to compete with PKC and downregulate MAPK/JNK and PI3K/AKT signaling.

   Evidence Reciprocal co-IP, mass spectrometry, GST pull-down, RNA-Seq, and gain/loss-of-function assays with PLC inhibitor co-treatment

   PMID:34657150

   Open questions at the time

   • Structural basis of GNA14–RACK1 competition with PKC not resolved
   • Single lab
7. 2021 Medium

   Established GNA14 as a tumor suppressor in hepatocellular carcinoma acting through Notch1/RB activation and JMJD6 suppression, and identified its epigenetic silencing by HBx.

   Evidence In vitro gain/loss-of-function, subcutaneous/lung colonization/orthotopic liver tumor models, methyl-target sequencing

   PMID:33500727

   Open questions at the time

   • Direct mechanism by which GNA14 promotes Notch1 cleavage unclear
   • Single lab
8. 2023 Medium

   Provided genetic in vivo evidence for an oncogenic role in colorectal cancer via ERK and β-catenin S675 phosphorylation.

   Evidence siRNA knockdown in CRC lines, Gna14 knockout × Apc mice, and Western blot for p-ERK and p-β-catenin

   PMID:37760541

   Open questions at the time

   • Whether wild-type GNA14 signaling or a mutant drives the effect not separated
   • Single lab
9. 2024 Medium

   Confirmed in vivo that the p.Gln205Leu mutation drives MAPK and angiogenic programs and produces vascular phenotypes, reinforcing the original oncogenic mechanism.

   Evidence Whole-exome/targeted deep sequencing, transcriptomic analysis, and mouse xenograft model

   PMID:38917801

   Open questions at the time

   • Effectors bridging mutant Gαq to angiogenic transcription not enumerated
   • Single lab

• It remains unresolved what determines GNA14's context-dependent switch between oncogene (endometrial, colorectal, vascular) and tumor suppressor (hepatocellular), and how its receptor coupling and effector selection differ across these tissues.
• No unified model reconciling pro- and anti-tumorigenic functions
• Upstream GPCRs coupling to GNA14 in each tissue not identified
• Structural consequences of p.Gln205Leu on effector binding not characterized