Huang W, Alessandrini A, Crews C M, Erikson R L
Department of Cellular and Developmental Biology, Harvard University, Cambridge, MA 02138.
Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):10947-51. doi: 10.1073/pnas.90.23.10947.
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.
在Sf9细胞中产生的重组Mek1和Raf-1蛋白在体内和体外均紧密结合，这显然不依赖于其他因素或Mek1或Raf-1的激酶活性。该复合物可被两种针对Raf-1肽产生的多克隆抗体破坏。与Raf-1共感染可使Mek1激活超过150倍，与Raf-1和Mek1共感染可使Erk1激活约90倍。Raf-1对Mek1的激活仅涉及丝氨酸磷酸化，其与Mek1激活程度成正比。磷酸肽图谱表明Mek1上有一个单一的Raf-1磷酸化位点。
