PKC Isoenzymes and Cell Proliferation

Investigations into die expression of distinct PKC isoenzymes in various tissues revealed a highly variable tissue distribution. PKCa and PKCX are ubiquitously expressed. Brain contains all isoenzymes, whereas others such as skin and skeletal muscle contain only a few (Blobe et al., 1994). Such a different pattern of expression suggests Aat the PKC isoenzymes play different roles in the tissue of expression and do not suggest a general role of all isoenzymes in cell proliferation. In many publications an influence of PKC on cell proliferation has been reported. 

Overexpression of PKC( has been reported to be required for mitogenic maturation of Xenopus oocytes and led to deregulation of growth control in mouse fibroblasts (Berra et al., 1993). However, these effects of PKC in Xenopus oocytes seem not to be clear (Carnero et al., 1995). In U937 monocytic leukemia cells PKC( overexpression decreased proliferation rate and saturation density, indicating the induction of differentiation (Ways et al., 

PKC seems to be involved in murine keratinocyte proliferation. A correlation between PKCfi expression and enhanced cell proliferation was also observed for NIH3T3 mouse fibroblasts overexpressing human PKCp (Rennecke et al., 1999). 

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