Protein kinase C isoenzymes in rat and human cardiovascular tissues

Abstract

1 We have compared the expression of protein kinase C (PKC) activity and immuno-detectable isoenzymes in cytosolic and membrane extracts of rat and human cardiovascular tissues (heart, kidney, aorta, saphenous vein). Experiments were performed in raw extracts and upon combined diethylaminoethylcellulose (DEAE) and phenylsepharose column chromatography. 2 PKC activity that bound to DEAE mostly eluted with 200 mM NaCl. DEAE-puri®ed PKC from all tissues except rat kidney bound almost quantitatively to phenylsepharose and eluted with 0.5 ± 0 M NaCl. 3 Immunoblots with an antibody against classical PKCs and the activator pro®le for phosphatidylserine, diolein and Ca 2+ revealed that the PKC from rat kidney, which did not bind to phenylsepharose, was most probably due to a proteolytically-generated, constitutively active PKC which is not under the control of a regulatory subunit. 4 Studies in the reference tissue, rat brain, demonstrated that all PKC isoenzymes investigated (classical PKCs a, b, g, new PKCs d, e, Z, y, and atypial PKCs z, l, i) have similar DEAE and phenylsepharose chromatography elution pro®les. In the functional assay an inhibitor of all known PKC isoenzymes, bisindolylmaleimide, and a speci®c inhibitor of classical PKCs, GoÈ 6976, both inhibited PKC from rat brain completely and with high potency indicating that the functional assay preferentially detects classical PKC isoenzymes. 5 Each PKC isoenzyme had a tissue-speci®c expression pro®le which was similar in rat and man. The classical PKCa, the new PKCs d and e and all atypical PKCs were detectable in most tissues, whereas the PKCb and PKCg were not detected in any pheripheral tissue; PKCZ and PKCy were found in some tissues. 6 We conclude that combined DEAE and phenylsepharose chromatography is useful to enrich and detect PKC isoenzymes; no major species dierences in tissues-speci®c expression patterns appear to exist between rat and man.

Differences in the Expression of Protein Kinase C Isoforms and Its Translocation After Stimulation With Phorbol Ester Between Young-Adult and Middle-Aged Ventricular Cardiomyocytes Isolated From Fischer 344 Rats.

“…However, based on those results, it is widely accepted that PKC-, -, -, and -are present in adult rat isolated cardiomyocytes. [18][19][20][21][22] We demonstrated in preliminary experiments that PKC-, -, and -are the dominant isoforms in isolated cardiomyocytes from both young-adult and middle-aged rats, although a small amount of PKC-ll is also present. Therefore, we used these 4 isoforms to investigate the age-related changes in PKC isoform expression in the present study, which demonstrated that only PKC-decreased in older cardiomyocytes.…”

Designing Heart Performance by Gene Transfer

“…The PKC family consists of at least 12 different isoforms, and the characteristics of the 3 subclasses have been reviewed in detail (173,190,619,838). Adult cardiac myocytes in most mammalian species express four major isoforms, including classical PKC-␣, novel class PKC-␦ and -, and to a lesser extent atypical PKC- (213,713,714). Several pathophysiological conditions and heart failure in humans are associated with increased expression of PKC-␣ and -␦, plus the appearance of PKC-␤, another classical isoform (77,648).…”

Protein kinase Cα participates in activation of store-operated Ca2+ channels in human glomerular mesangial cells

“…All isoforms express distinct enzymological properties, differential tissue distribution, different substrate specificity, and specific subcellular localization with distinct modes of cellular regulation (4,6,9,18,23,36,38). For example, PKC␣, ␦, ⑀, and , but not PKC␤, which is strongly expressed in cardiomycytes, were detected in rat MC as determined by Western blotting (18,19,42).…”