PRKCH Protein, Human (Active, sf9, GST)

PRKCA is a calcium-independent, phospholipid- and diacylglycerol (DAG)-dependent serine/threonine-protein kinase involved in regulating cell differentiation in keratinocytes and pre-B cell receptor signaling, mediating epithelial tight junction integrity and foam cell formation, and required for glioblastoma proliferation and apoptosis prevention in MCF-7 cells. In keratinocytes, PRKCA binds and activates the tyrosine kinase FYN, blocking epidermal growth factor receptor (EGFR) signaling to induce growth arrest and differentiation. It associates with the cyclin CCNE1-CDK2-CDKN1B complex, inhibiting CDK2 activity to promote RB1 dephosphorylation and G1 arrest. Together with RALA, PRKCA drives actin depolymerization, essential for keratinocyte differentiation. In pre-B cell receptor signaling, PRKCA acts downstream of BLNK by upregulating IRF4, facilitating L chain gene rearrangement. It regulates tight junctions (TJs) by phosphorylating occludin (OCLN) on threonine residues, crucial for TJ assembly and maintenance. In collaboration with PLD2 and TLR4 signaling, PRKCA contributes to lipopolysaccharide (LPS)-induced RGS2 downregulation and foam cell formation. Upon PMA stimulation, PRKCA promotes glioblastoma proliferation via mTOR, PI3K/AKT, and ERK1-dependent ELK1 phosphorylation. It protects glioblastoma cells from irradiation-induced apoptosis by inhibiting caspase-9 activation. In camptothecin-treated MCF-7 cells, PRKCA regulates NF-kappa-B upstream signaling through IKBKB activation, conferring resistance to DNA damage-induced apoptosis. PRKCA enhances ATF2's oncogenic nuclear functions while suppressing its mitochondrial apoptotic role. By phosphorylating ATF2, PRKCA promotes its nuclear retention and transcriptional activity while inhibiting mitochondrial localization.