Protein kinase C enzyme family (PKC)

The **protein kinase C enzyme family** (PKC) comprises a group of related **serine/threonine kinases** that play essential roles in cellular signal transduction[1][5]. PKCs regulate other proteins by phosphorylating them on serine and threonine residues, and their activation is mediated by signals such as increased concentrations of diacylglycerol (DAG) and, for some isoforms, calcium ions (Ca²⁺)[1][2]. PKCs are divided into three main subfamilies: - **Conventional (cPKC: α, βI, βII, γ)** — require both calcium and DAG for activation. - **Novel (nPKC: δ, ε, η, θ)** — require DAG but not calcium. - **Atypical (aPKC: ζ, ι/λ)** — require neither calcium nor DAG for activity[1][2][5]. PKC family members modulate diverse processes, including cell growth, proliferation, survival, migration, differentiation, and apoptosis. Aberrant PKC signaling is implicated in multiple human diseases, from **cancer** and **cardiovascular disease** to **neurodegeneration** and **inflammation**[5][8]. PKC inhibitors and modulators have been explored as therapeutic agents, though targeting individual isoforms presents challenges due to high structural similarity and complex biology. This target is considered druggable and has been the focus of considerable pharmaceutical research, although **off-target effects** and toxicity remain significant hurdles. Individual PKC **isoforms** may serve as both **biomarkers** and **therapeutic targets** in various disease contexts[1][5][2].

Other names

Protein kinase CPKCProtein kinase C enzymesAGC kinase family (includes PKC as subgroup)ABC kinase subfamily

Inhibition of serine/threonine phosphorylation; Allosteric modulation of kinase activity; Competition with diacylglycerol for binding; Inhibition of cofactor binding (Calcium, DAG)