PRKCQ

PRKCQ encodes PKCθ, a serine/threonine kinase whose expression and catalytic activity couple upstream regulatory inputs to proliferation, survival, and inflammatory signaling across diverse cell types (PMID:27663795). In megakaryocytic cells, PRKCQ is a direct transcriptional target of RUNX1, which binds a consensus site in the PRKCQ promoter and drives PKCθ protein expression (PMID:21252065). In breast epithelial and triple-negative breast cancer cells, PKCθ kinase activity stimulates ERK/MAPK signaling and Rb phosphorylation to promote cell-cycle progression and growth-factor-independent proliferation, while also conferring anoikis resistance, anchorage-independent survival, and migration (PMID:27663795); the same catalytic activity suppresses pro-apoptotic Bim to limit chemotherapy-induced apoptosis, since Bim re-suppression reverses the sensitizing effect of PRKCQ loss (PMID:32600444). In oral squamous cell carcinoma, PRKCQ sustains autophagic flux by maintaining TRIM22 expression and supporting lysosomal function and autophagosome–lysosome fusion, with TRIM22 overexpression rescuing the PRKCQ-knockdown phenotype (PMID:41764502). Comprehensive germline knockout shows PRKCQ is dispensable for spermatogenesis and male fertility in mice despite high testicular expression (PMID:40051302). The human gene spans ~62 kb on chromosome 10p15 across 15 coding exons (PMID:9790596). The biochemical events directly linking PKCθ catalysis to ERK, NF-κB, and TRIM22 outputs have not been reconstituted in the available corpus.

1. 1998 Medium

   Established the genomic architecture of human PRKCQ, providing the structural foundation for studying its regulation and conservation.

   Evidence P1 genomic library cloning, FISH, and long-range PCR sequencing defining all exon-intron boundaries

   PMID:9790596

   Open questions at the time

   • Does not address protein function or expression control
   • No isoform or promoter-element characterization
2. 2011 High

   Answered how PRKCQ expression is controlled in megakaryocytes, identifying RUNX1 as a direct transcriptional driver of the gene.

   Evidence ChIP, EMSA, promoter-reporter mutagenesis, siRNA knockdown and overexpression in megakaryocytic cells

   PMID:21252065

   Open questions at the time

   • Functional role of PKCθ in megakaryocytes not defined
   • Transcriptional control in other lineages unknown
3. 2016 Medium

   Placed PKCθ kinase activity upstream of ERK/MAPK and Rb phosphorylation, showing catalytic activity is required for proliferation and oncogenic transformation phenotypes in breast cells.

   Evidence Kinase-active vs kinase-inactive cDNA, AEB071 inhibitor, immunoblot for p-Rb/p-ERK, anoikis and xenograft assays in MCF-10A and TNBC lines

   PMID:27663795

   Open questions at the time

   • Direct kinase substrate linking PKCθ to ERK not identified
   • Mechanism of ERK activation not reconstituted
4. 2020 Medium

   Defined a survival mechanism by which PKCθ catalytic activity suppresses pro-apoptotic Bim to confer chemotherapy resistance in TNBC.

   Evidence WT vs kinase-inactive overexpression, knockdown, apoptosis assays, and Bim-suppression rescue in MCF-10A and TNBC lines

   PMID:32600444

   Open questions at the time

   • Biochemical step between PKCθ and Bim regulation unknown
   • Transcriptional vs post-translational control of Bim unresolved
5. 2021 Low

   Linked Prkcq to Schwann cell proliferation, migration, and apoptosis via β-catenin and c-fos/c-jun pathways during nerve injury.

   Evidence Rat sciatic nerve injury model with Schwann cell gain/loss-of-function and pathway immunoblotting

   PMID:34418453

   Open questions at the time

   • Pathway placement based on expression-level readouts without mechanistic reconstitution
   • Direct kinase targets not identified
6. 2025 Medium

   Established PRKCQ as an upstream regulator of autophagic flux, acting through TRIM22 to maintain lysosomal function and autophagosome–lysosome fusion in OSCC.

   Evidence shRNA knockdown, transcriptomics, autophagic flux and lysosomal assays, TRIM22 overexpression rescue, and xenografts in OSCC cells

   PMID:41764502

   Open questions at the time

   • Mechanism by which PRKCQ maintains TRIM22 expression unknown
   • Whether kinase activity is required not tested
7. 2025 Medium

   Tested the requirement for PRKCQ in spermatogenesis, showing it is dispensable for male fertility despite high testicular expression.

   Evidence CRISPR/Cas9 germline knockout mice with histology, sperm analysis, and fertility testing

   PMID:40051302

   Open questions at the time

   • Possible compensation by other PKC family members not excluded
   • Testicular function of PKCθ remains undefined
8. 2025 Low

   Implicated Prkcq in ILC2 cytokine production and tissue-resident macrophage accumulation during chronic pancreatitis.

   Evidence Single-cell sequencing, DBTC pancreatitis mouse model, and siRNA knockdown of Prkcq in ILC2s

   PMID:40706949

   Open questions at the time

   • No direct biochemical mechanism established
   • Pathway placement inferred from cytokine readouts
9. 2026 Low

   Identified PRKCQ as a required mediator of anti-adipogenic effects and as coupled to NF-κB during melanoblast differentiation.

   Evidence High-fat-diet adipogenesis model with PRKCQ deletion, and CAP-treated vitiligo/melanoblast model with NF-κB immunoblotting

   PMID:41596924 PMID:42170107

   Open questions at the time

   • Mechanistic link between PRKCQ kinase activity and adipogenic transcription factors not established
   • Correlative NF-κB placement without mutagenesis

• The direct catalytic substrates of PKCθ that connect it to ERK/MAPK, NF-κB, Bim, and TRIM22 outputs remain unidentified across all contexts.
• No reconstituted phosphorylation substrate reported
• No structural model of PKCθ in these signaling complexes
• Kinase-activity requirement untested for autophagy and NF-κB phenotypes