Multiple biological responses activated by nuclear protein kinase C

Protein kinase C is a family of serine-threonine kinases that are physiolog ically activated by a number of lipid cofactors and are important transduce rs in many agonist-induced signaling cascades. To date, 12 different isozym es of this kinase have been identified and are believed to play distinct re gulatory roles. Protein kinase C was thought to reside in the cytosol in an inactive conformation and translocate to the plasma membrane upon cell act ivation by different stimuli. Nevertheless, a growing body of evidence has illustrated that this family of isozymes is capable of translocating to oth er cellular sites, including the nucleus. Moreover, it seems that some prot ein kinase C isoforms are resident within the nucleus. A wealth of data is being accumulated, demonstrating that nuclear protein kinase C isoforms are involved in the regulation of several critical biological functions such a s cell proliferation and differentiation, neoplastic transformation, and ap optosis. In this review we will discuss the most significant findings conce rning nuclear protein kinase C which have been published during the past 5 years. (C) 1999 Wiley-Liss, Inc.