iBet uBet web content aggregator. Adding the entire web to your favor.
iBet uBet web content aggregator. Adding the entire web to your favor.



Link to original content: http://pubmed.ncbi.nlm.nih.gov/8019005/
MEK-1 phosphorylation by MEK kinase, Raf, and mitogen-activated protein kinase: analysis of phosphopeptides and regulation of activity - PubMed Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1994 Feb;5(2):193-201.
doi: 10.1091/mbc.5.2.193.

MEK-1 phosphorylation by MEK kinase, Raf, and mitogen-activated protein kinase: analysis of phosphopeptides and regulation of activity

A M Gardner  1 , R R Vaillancourt, C A Lange-Carter, G L Johnson
Affiliations
Free PMC article

MEK-1 phosphorylation by MEK kinase, Raf, and mitogen-activated protein kinase: analysis of phosphopeptides and regulation of activity

A M Gardner et al. Mol Biol Cell. 1994 Feb.
Free PMC article

Abstract

MEK-1 is a dual threonine and tyrosine recognition kinase that phosphorylates and activates mitogen-activated protein kinase (MAPK). MEK-1 is in turn activated by phosphorylation. Raf and MAPK/extracellular signal-regulated kinase kinase (MEKK) independently phosphorylate and activate MEK-1. Recombinant MEK-1 is also capable of autoactivation. Purified recombinant wild type MEK-1 and a mutant kinase inactive MEK-1 were used as substrates for MEKK, Raf, and autophosphorylation. MEK-1 phosphorylation catalyzed by Raf, MEKK, or autophosphorylation resulted in activation of MEK-1 kinase activity measured by phosphorylation of a mutant kinase inactive MAPK. Phosphoamino acid analysis and peptide mapping identified similar MEK-1 tryptic phosphopeptides after phosphorylation by MEK kinase, Raf, or MEK-1 autophosphorylation. MEK-1 is phosphorylated by MAPK at sites different from that for Raf and MEKK. Phosphorylation of MEK-1 by MAPK does not affect MEK-1 kinase activity. Several phosphorylation sites present in MEK-1 immunoprecipitated from 32P-labeled cells after stimulation with epidermal growth factor were common to the in vitro phosphorylated enzyme. The major site of MAPK phosphorylation in MEK-1 is threonine 292. Mutation of threonine 292 to alanine eliminates 90% of MAPK catalyzed phosphorylation of MEK-1 but does not influence MEK-1 activity. The results demonstrate that MEKK and Raf regulate MEK-1 activity by phosphorylation of common residues and thus, two independent protein kinases converge at MEK-1 to regulate the activity of MAPK.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Nature. 1992 Jul 30;358(6385):417-21 - PubMed
    1. J Biol Chem. 1992 Jul 15;267(20):14373-81 - PubMed
    1. Science. 1992 Oct 16;258(5081):478-80 - PubMed
    1. Proc Natl Acad Sci U S A. 1993 Jan 1;90(1):173-7 - PubMed
    1. J Biol Chem. 1993 Jan 25;268(3):1960-4 - PubMed

Publication types

MeSH terms