Protein kinase C C1 domain (PKC C1 domain) (PKC C1 domain)

The Protein kinase C (PKC) C1 domain is a conserved, cysteine-rich motif that serves as the primary regulatory site for sensing the lipid second messenger diacylglycerol (DAG) (UniProt, 2023). This domain is present in conventional and novel PKC isoforms, where it coordinates two zinc ions to form a hydrophobic pocket that accommodates DAG or exogenous ligands like phorbol esters (PubMed, PMID: 15680311). Upon ligand binding, the C1 domain facilitates the translocation of the PKC enzyme from the cytosol to the plasma membrane, a critical step in various signal transduction pathways including cell growth and differentiation (NCBI, 2022). In the context of disease, dysregulation of C1 domain-mediated signaling is implicated in oncogenesis and neurodegenerative conditions like Alzheimer's disease (StatPearls, 2023). Pharmacologically, the C1 domain is targeted by natural products such as bryostatins and prostratin, which are being investigated for their potential to reverse HIV latency and treat cognitive deficits (PubMed, PMID: 30254001). However, therapeutic development is challenged by the need for isoform selectivity to avoid adverse effects like systemic inflammation or unintended tumor promotion (Nature Reviews Drug Discovery, 2017).

Other names

C1 domainPhorbol ester/diacylglycerol-binding domainCys-rich domainDAG-binding domainProtein kinase C conserved region 1

Ligands bind to the C1 domain to mimic the natural activator diacylglycerol (DAG), inducing a conformational change that recruits the PKC enzyme to the cell membrane and releases the autoinhibitory pseudosubstrate from the catalytic site, thereby activating the kinase (PubMed, PMID: 15680311).