Effect of okadaic acid on membrane protein phosphorylation in human erythrocytes.
Okadaic acid, penetrating the human erythrocytes, almost completely inhibits P-Ser-protein phosphatase activity, whereas it unaffects Ser/Thr-protein kinase activity (casein kinases CKI and CKII), thus promoting a marked increase of the endogenous Ser-phosphorylation level of membrane proteins, such as cytoskeletal spectrin beta-subunit (band 2) and transmembrane band 3 protein. By contrast, the Tyr-phosphorylation state of band 3 protein is practically unaffected by okadaic acid, being unaffected both Tyr-protein kinase and P-Tyr-protein phosphatase activities.
Istituto di Medicina Interna, Università di Padova, Italy.
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Bordin
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Clari
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Bellato
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Tessarin
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Moret
D047388:Casein Kinases; D003600:Cytosol / Q000201:enzymology; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D004912:Erythrocytes / Q000201:enzymology; D004988:Ethers, Cyclic / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000097:blood*; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000097:blood; D010766:Phosphorylation; D011494:Protein Kinases / Q000097:blood
D004988:Ethers, Cyclic; D008565:Membrane Proteins; D019319:Okadaic Acid; D011494:Protein Kinases; D047388:Casein Kinases; D010749:Phosphoprotein Phosphatases