Module 2: Figure PKC structure and activation
Structure of PKC isoforms and activation mechanism of the conventional protein kinase C (cPKC) isoforms.
The nine genes that code for protein kinase C (PKC) fall into three families. Conventional PKCs (cPKCs) have a domain structure that has an N-terminal pseudosubstrate (PS) domain followed by regulatory domains (C1 and C2), which are responsible for binding the diacylglycerol (DAG) and Ca2+ responsible for membrane targeting, an ATP-binding C3 domain and the C4 catalytic domain. The C1 region is present as a tandem repeat (C1A and C1B). The PS domain has an autoinhibitory function in that it associates with the catalytic site on C4, thus preventing it from phosphorylating its substrates. Novel PKCs (nPKCs) have a similar domain structure, except that they have a C2-like domain that does not bind Ca2+. Atypical (aPKCs) also lack a C2 domain, and the C1 domain is small and fails to bind DAG. The illustration at the bottom indicates how cPKC is activated, as described in the text.