Figure 1

Diagrammatic representation of the domain structure of PRKC isoforms. Conventional, cPRKC isoforms (PRKCA, PRKCB1, PRKCB2, and PRKCG also known as PRKCα,β1,β2, and γ, respectively) are diacylglycerol (DAG) sensitive and Ca2+ responsive (C2 is the Ca2+-binding domain, C1 features the DAG and phosphatidylserine binding; at the N-terminal of the C1 domain is located a pseudosubstrate site that regulates PRKC activity). Novel, nPRKC isoforms (PRKCD, PRKCE, PRKCH, PRKCQ, and PRCKM also known as PRKC δ,ε,η,θ, and μ, respectively) are DAG sensitive but Ca2+ insensitive (the C2-like domain do not retain Ca2+-coordinating residues). Atypical, aPRKC isoforms (PRKCZ and PRKCI, also known as PRKC ζ and λ, respectively) are regulated by phospholipidic mediators products including phosphatidylinositol 3,4,5-triphosphate). All kinases have a conserved kinase core (C4) and a C3 domain, which represents the ATP-binding site (for a review see [12].