title: Tissue distribution and developmental expression of protein kinase C isozymes.
abstract: Protein kinase C is a ubiquitous enzyme found in a variety of mammalian tissues and is especially highly enriched in brain and lymphoid organs. Based on biochemical and immunological analyses, we have identified three types of protein kinase C isozyme (designated types I-III) from rat brain. Monospecific antibodies against each of the protein kinase C isozymes were prepared for the determination of tissue distribution, subcellular localization, and developmental changes of these enzymes. The various protein kinase C isozymes were found to be distinctively distributed in different tissues: the type I enzyme in brain; the type II enzyme in brain, pituitary and pineal glands, spleen, thymus, retina, lung, and intestine; and the type III enzyme in brain, pineal gland, retina, and spleen. The rat brain enzymes were differentially distributed in different subcellular fractions. The type I enzyme appeared to be most lipophilic and was recovered mostly in the particulate fractions (80-90%) regardless of the EGTA- or Ca2+-containing buffer used in the homogenization. Significant amounts (30-40%) of the type II and III enzymes were recovered in the cytosolic fraction with EGTA-containing buffer. The expressions of different protein kinase C isozymes appear to be differently controlled during development. In rat brain, both type II and III enzymes were found to increase progressively from 3 days before birth up to 2-3 weeks of age and remained constant thereafter. However, the expression of the type I enzyme displayed a different developmental pattern; it was very low within 1 week, and an abrupt increase was observed between 2 and 3 weeks of age. In thymus, the type II enzyme was found to be maximal shortly after birth; whereas the same kinase in spleen was very low within 2 weeks of age, and a significant increase was observed between 2 and 3 weeks. These results demonstrate that protein kinase C isozymes are distinctively distributed in different tissues and subcellular locales and that their expressions are controlled differently during development.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology / Q000254:growth & development / Q000648:ultrastructure; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005333:Fetus / Q000201:enzymology; D006128:Growth; D007118:Immunoassay; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000201:enzymology / Q000254:growth & development; D013347:Subcellular Fractions / Q000201:enzymology; D013950:Thymus Gland / Q000201:enzymology / Q000254:growth & development; D014018:Tissue Distribution
chemical_list: D007527:Isoenzymes; D004533:Egtazic Acid; D011493:Protein Kinase C; D002118:Calcium