Stimulation by insulin of a serine kinase in human platelets that phosphorylates and activates the cGMP-inhibited cAMP phosphodiesterase

Summary, in English

We previously reported that insulin stimulation of human platelets induces serine phosphorylation and activation of the cGMP-inhibited cAMP phosphodiesterase (cGI-PDE). Here, we describe methods to detect and partially purify an insulin-stimulated cGI-PDE kinase (cGI-PDE ISK) from lysates of platelets incubated with insulin. Incubation of human platelets with 10(-8) M insulin increased cGI-PDE ISK activity two-fold. The DEAE-Sephacel-purified cGI-PDE ISK phosphorylated the cGI-PDE on serine in a time- and concentration-dependent manner resulting in an increased incorporation of about 0.2 mol of [32P]/mol of cGI-PDE and 15-20% increase in cGI-PDE activity. The phosphorylation of cGI-PDE was not affected by 10 microM PKI, 1 microgram/ml of heparin, 3 mM CaCl2 or 1 mM MnCl2. cGI-PDE ISK did not adsorb to antiphosphotyrosine antibodies. To maintain its activation it was necessary to add protein phosphatase inhibitors to the lysate-buffers. All of these findings are consistent with the conclusion that a serine/threonine phosphorylation of the cGI-PDE ISK is involved in its activation by insulin.

• Författare: Pilar Lopez-Aparicio; Per Belfrage; Vincent C Manganiello; Tetsuro Kono; Eva Degerman
• Avdelning/ar: Signaltransduktionsforskning
• Publiceringsår: 1993
• Språk: Engelska
• Sidor: 1137-1144
• Publikation/Tidskrift/Serie: Biochemical and Biophysical Research Communications
• Volym: 193
• Issue: 3
• Länkar: http://dx.doi.org/10.1006/bbrc.1993.1744
• Dokumenttyp: Artikel i tidskrift
• Förlag: Elsevier
• Ämne: Biological Sciences
• Status: Published
• Forskningsgrupp: Insulin Signal Transduction
• ISBN/ISSN/Övrigt: ISSN: 1090-2104