Activation of an insulin‐stimulated S6 kinase in 3T3 L1 cell‐free extracts by proteolysis

FEBS Letters

de Herreros, Antonio Garcia¹ 

[1] Memorial Sloan-Kettering Cancer Center, Program in Molecular Biology and Cornell University Graduate School of Medical Sciences, Sloan-Kettering Division, New York, NY, USA

关键词: Protein S6 kinase;    Proteolysis;    PK-C;    protein kinase dependent on phospholipids and calcium;    TPA;    12-tetradecanoylphorbol 13-acetate;    DME medium;    Dulbecco's modified Eagle's medium;   

DOI  :  10.1016/0014-5793(89)80430-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Using chromatography on a Fast S-Sepharose column, the insulin-stimulated S6 kinase can be resolved from other S6 kinases present in 3T3 L1 cell extracts. Only one S6 kinase is greatly activated by insulin (4–5-fold) and phosphorylates S6 with a high stoichiometry (4–5 mol phosphate per mol S6). This insulin-dependent S6 kinase can be activated in cell-free extracts by incubation with high concentrations of Ca²⁺. This activation is blocked by protease inhibitors such as leupeptin and is mimicked by trypsin. The stimulation does not require the presence of the protein kinase dependent on phospholipids and calcium (PK-C) in the cell extracts. The level of stimulation produced by proteolysis in the cell extracts is comparable to that reached in vivo by incubation with insulin.

【 授权许可】

Unknown