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Eva Degerman

Eva Degerman

Professor

Eva Degerman

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

Author

  • Pilar Lopez-Aparicio
  • Per Belfrage
  • Vincent C Manganiello
  • Tetsuro Kono
  • Eva Degerman

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.

Department/s

  • Insulin Signal Transduction

Publishing year

1993

Language

English

Pages

1137-1144

Publication/Series

Biochemical and Biophysical Research Communications

Volume

193

Issue

3

Document type

Journal article

Publisher

Elsevier

Topic

  • Biological Sciences

Status

Published

Research group

  • Insulin Signal Transduction

ISBN/ISSN/Other

  • ISSN: 1090-2104