Protein kinase Cα (PKCα):: Regulation and biological function

Protein kinase Calpha (PKCalpha) is a serine/threonine kinase and a member of the conventional (classical) PKCs (cPKCs), which have four conserved (C1 to C4) regions. This ubiquitously expressed PKC isotype is activated in response to many different kinds of stimuli and translocates from cytosol to the specialized cellular compartments (nucleus, focal adhesion, caveolae, etc.) where it is presumed to work. Therefore, PKCalpha has been implicated in a variety of cellular functions including proliferation, apoptosis, differentiation, motility, and inflammation. However, the responses induced by activation or overexpression of PKCalpha vary depending on the types, and sometimes conditions, of cells. For example, in some types of cells, PKCalpha is implicated in cell growth. In contrast, it may play a role in cell cycle arrest and differentiation in other types of cells. Therefore, alterations of cell responses induced by PKCalpha are not an intrinsic property of this isoform. The responses are modulated by dynamic interactions with cell-type specific factors: substrates, modulators and anchoring proteins.