Different phosphorylated forms of an insulin‐sensitive glycosylphosphatidylinositol from rat hepatocytes

FEBS Letters

Mato, Jose M.¹  Villalba, Mayte¹  Corrales, Fernando J.¹  Ruiz-Albusac, Juan M.²  Clemente, Rosa¹  Merida, Isabel¹ 

[1] Metabolismo, Nutricion y Hormonas, Fundacion Jimenez Diaz and Instituto de Investigaciones Biomedicas del CSIC, Reyes Catolicos 2, Madrid 28040, Spain;Departamento de Bioquimica, Facultad de Medicina, Universidad Complutense, Madrid 28040, Spain

关键词: Insulin action;    Glycosylphosphatidylinositol;    (Rat hepatocyte);   

DOI  :  10.1016/0014-5793(88)80325-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Labeling with [³H]galactose was employed to isolate a glycosylphosphatidylinositol from rat hepatocytes which might be involved in the action of insulin. The polar head group of this glycosylphosphatidylinositol was generated by phosphodiesterase hydrolysis with a phosphatidylinositol-specific phospholipase C from Bacillus cereus. By Dowex AG1 × 8 chromatography the polar head group could be separated into three radioactive peaks eluting at 100 mM (peak I), 200 mM (peak II) and 500 mM (peak III) ammonium formate, respectively. Peak III was the most active as an inhibitor of the cAMP-dependent protein kinase. Treatment of peak III with alkaline phosphatase markedly reduced its activity on cAMP-dependent protein kinase. When peaks I, II or III were treated with alkaline phosphatase and analyzed again by Dowex AG1 × 8 chromatography, the radioactivity eluted with the aqueous fraction. The above results indicate that the polar head group of the insulin-sensitive glycosylphosphatidylinositol from rat hepatocytes exists in three different phosphorylated forms and that the biological activity of this molecule depends on its phosphorylation state.

【 授权许可】

Unknown