SELECTIVE DISTRIBUTION OF MULTIPLE PROTEIN-KINASE-C ISOFORMS IN MOUSECEREBELLAR CORTEX

An immunohistochemical study concerning the distribution of protein ki nase C isoforms, a lipid-regulated serineithreonine kinase essential f or signal transduction, was performed in mice cerebellar cortex, with particular emphasis on the localization of -iota and -lambda isozymes. By the means of immunoblotting analyses we detected the presence of 1 1 PKC subspecies in whole cerebellar extracts. Immunoreactivity on cry ostat sections revealed, using polyclonal and monoclonal antibodies, t hat a few isoforms were widely but discretely distributed in all three cortical layers (molecular, granular and Purkinje cells) whereas othe r isozymes were present in a limited neuronal compartment. Overall, th e distribution of several isoforms was in agreement with data obtained by other authors using rat cerebellum. As far as -iota and -lambda is ozymes were concerned, we found them abundantly expressed in endotheli al cells. Moreover, protein kinase C-lambda was also present in the bo dy of Purkinje cell, conceivably associated with a 200-kDa neurofilame nt component. In all, these results hint at the possibility that in th e cerebellar cortex at least some protein kinase C isoforms are involv ed in functions other than signal transduction at the synaptic level.