Distribution of MAP kinase, S6 kinase, and casein kinase II in rat tissues: activation by insulin in spleen.
We examined the distribution of mitogen-activated protein (MAP) kinase, S6 kinase, and casein kinase II (CK-II) in the muscle, spleen, brain, and testes of Wistar rats. It was observed that spleen extracts contained the highest activity of all the kinases. Anion-exchange chromatography of spleen extracts by a MonoQ column resolved a single peak of myelin basic protein phosphotransferase activity that eluted after the usual position of the previously described p42 and p44 MAP kinases. Immunoblotting of the peak fractions with anti-MAP kinase antibody did not detect any immunoreactive bands that coincided with the activity peak, suggesting that the activity may represent a potentially novel MAP kinase. The MonoQ fractionation also resolved a single peak of phosvitin phosphotransferase activity which coincided with the intensity of two immunoreactive bands of 39 and 43 kilodaltons that were detected with antibodies against CK-II. The chromatographic behaviour and immunoblotting data indicate that the phosvitin kinase peak represented CK-II and suggested that the rat spleen CK-II had a molecular structure of alpha alpha ' beta 2. Furthermore, using an intact rat model, we showed that the potentially novel spleen MAP kinase and CK-II were markedly activated following intravenous injection of insulin. The significance of these findings remains to be determined.
Hei
Y J
YJ
Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada.
Chen
X
X
Diamond
J
J
McNeill
J H
JH
D000818:Animals; D001921:Brain / Q000201:enzymology; D047390:Casein Kinase II; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1; D009132:Muscles / Q000201:enzymology; D009928:Organ Specificity; D017346:Protein Serine-Threonine Kinases / Q000032:analysis* / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000032:analysis* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D019893:Ribosomal Protein S6 Kinases; D013154:Spleen / Q000201:enzymology*; D013737:Testis / Q000201:enzymology
D007328:Insulin; D011505:Protein-Tyrosine Kinases; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D019893:Ribosomal Protein S6 Kinases; D019950:Mitogen-Activated Protein Kinase 1