Open AccessRaf-1 forms a stable complex with Mek1 and activates Mek1 by serine phosphorylation.
Author(s) -
Weidong Huang,
Alessandro Alessandrini,
Craig M. Crews,
Raymond L. Erikson
Publication year - 1993
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.90.23.10947
Subject(s) - phosphorylation , serine , autophosphorylation , kinase , chemistry , phosphorylation cascade , microbiology and biotechnology , polyclonal antibodies , protein kinase a , biology , protein phosphorylation , antibody , immunology
Recombinant Mek1 and Raf-1 proteins produced in Sf9 cells undergo a tight association both in vivo and in vitro, which apparently does not depend on additional factors or the kinase activity of Mek1 or Raf-1. The complex can be disrupted by two polyclonal antibodies raised against Raf-1 peptides. Coinfection with Raf-1 activates Mek1 > 150-fold, and coinfection with Raf-1 and Mek1 activates Erk1 approximately 90-fold. The activation of Mek1 by Raf-1 involves only serine phosphorylation, which is directly proportional to the extent of Mek1 activation. Phosphopeptide maps suggest a single Raf-1 phosphorylation site on mek1.