Protein kinase C conventional and novel isoforms C1 domain (PKC C1 domain)

The C1 domain is a highly conserved, cysteine-rich structural motif found in conventional (alpha, beta I, beta II, gamma) and novel (delta, epsilon, eta, theta) isoforms of Protein Kinase C (PKC) (Newton, A. C., 2018, Chemical Reviews). It functions as a molecular switch that binds the lipid second messenger diacylglycerol (DAG) or exogenous ligands such as phorbol esters (Igomenos et al., 2013, Journal of Biological Chemistry). Upon ligand binding, the C1 domain facilitates the translocation of PKC from the cytosol to the plasma membrane or other organelle membranes, where the enzyme becomes catalytically active by releasing its pseudosubstrate from the kinase core (Kozikowski et al., 2003, Journal of Medicinal Chemistry). This activation triggers a cascade of phosphorylation events that regulate critical cellular processes including proliferation, differentiation, and apoptosis (UniProt P17252). Dysregulation of PKC signaling via the C1 domain is implicated in numerous pathologies, including oncogenesis, diabetic complications, and neurodegeneration (PubMed ID: 29120617). Consequently, the C1 domain is a significant pharmacological target, with compounds like bryostatin-1 and ingenol mebutate being utilized or investigated for their ability to modulate PKC activity in cancer, Alzheimer's disease, and actinic keratosis (PubChem CID 5280757).

Other names

DAG-binding domainPhorbol ester binding domainCysteine-rich domainC1a and C1b domainsPKC C1 region

Activation of Protein Kinase C through mimetic binding to the C1 domain, replacing diacylglycerol and inducing membrane translocation.