Activity of novel protein kinase C and distribution of protein kinase C theta in subcellular fractions of normal and Duchenne muscular dystrophic muscle.
Phospholipid-dependent, Ca(2+)-independent isoenzymes termed novel protein kinase C or nPKC, include PKC delta, epsilon, eta, theta and mu. Status and role of nPKC and PKC theta in Duchenne muscular dystrophic (DMD) condition is unknown. In the present study, we have shown that most of the nPKC isoforms are translocated to the membrane fraction of DMD tissue specimen. It is well established that translocation plays a key role in signal transduction by individual PKC isoforms. In our experiment, the increased association of nPKC isoform PKC theta to membrane was further confirmed by Western blot. Increased expression of PKC theta mRNA was identified by dot blot analysis. The above results suggest that, the alterations in nPKC location and increased expression of PKC theta observed is a result of modification of PKC-mediated signal transduction and cell function.