The protein kinase mos activates MAP kinase kinase in vitro and stimulates the MAP kinase pathway in mammalian somatic cells in vivo

FEBS Letters

Nebreda, Angel R.²  Hunt, Tim²  Gomez, Nestor¹  Cohen, Philip¹  Hill, Caroline³ 

[1] MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, Dundee DD1 4HN, UK;Imperial Cancer Research Fund Clare Hall Laboratories, South Mimms, Herts EN63LD, UK;Transcription Laboratory, Imperial Cancer Research Fund, London WC2A 3PX, UK

关键词: MAP kinase;    mos;    Elk-1;    Oncogene;    Protein phosphorylation;    Signal transduction;   

DOI  :  10.1016/0014-5793(93)80401-F

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The mos protooncogene encodes a serine/threonine protein kinase that is only expressed at significant levels in germ cells. Recombinant malE-mos protein (Xenopus mos protooncogene fused in frame to the maltose binding protein of E. coli) activates MAP kinase in cell-free extracts prepared from Xenopus oocytes and eggs. Here we show that malE-mos immunoprecipitates from Xenopus extracts phosphorylate and activate MAP kinase kinase in vitro, indicating that mos can function as a MAP kinase kinase kinase. Moreover, ectopic expression of mos in mammalian somatic cells, that lack any endogenous mos protein, triggers the activation of MAP kinase in vivo. These results identify the mos protooncogene as a direct activator of the MAP kinase pathway, with the potential to activate this kinase cascade even in cells where normally there is no expression of mos.

【 授权许可】

Unknown