Immunological identification of protein kinase C-alpha and protein kinase C-delta in cultured rat mesangial cells: differential sensitivity of the two isoforms towards the protein kinase inhibitor H7.
Rat mesangial cells contain both calcium-dependent protein kinase C (PKC) activity, which phosphorylates histone H1 and endogenous proteins, and calcium-independent, phospholipid-dependent PKC activity, which phosphorylates only endogenous proteins. The calcium-dependent PKC was identified as PKC alpha by immunoblot analysis and hydroxyapatite chromatography (HPLC). The calcium-insensitive, phospholipid-dependent isoform was identified as PKC delta using similar techniques. The inhibition of these two PKC isoforms by the protein kinase inhibitor H7 [1-(iso-quinolinyl sulphonyl)-2-methyl piperazine] was examined using both histone H1 and endogenous proteins as substrates. Phosphorylations catalyzed by the calcium-dependent PKC isoform alpha were almost 90% inhibited when histone H1 was used, and only 55% when endogenous proteins were the substrate. In contrast, the phosphorylation of endogenous proteins catalysed by the calcium-insensitive, phospholipid-dependent PKC delta was not significantly affected by the inhibitor.
Oudinet
J P
JP
Unité de recherche de néphrologie normale et pathologique, INSERM U 64, Paris, France.
Feliers
D
D
Pavlovic-Hournac
M
M
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005920:Glomerular Mesangium / Q000201:enzymology*; D015151:Immunoblotting; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000276:immunology / Q000302:isolation & purification*; D007546:Isoquinolines / Q000494:pharmacology; D008970:Molecular Weight; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000276:immunology / Q000302:isolation & purification*; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats
D007527:Isoenzymes; D007546:Isoquinolines; D010879:Piperazines; D011506:Proteins; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D002118:Calcium