Dual function of Ras in Raf activation.
The small guanine nucleotide binding protein p21(Ras) plays an important role in the activation of the Raf kinase. However, the precise mechanism by which Raf is activated remains unclear. It has been proposed that the sole function of p21(Ras )in Raf activation is to recruit Raf to the plasma membrane. We have used Drosophila embryos to examine the mechanism of Raf (Draf) activation in the complete absence of p21(Ras) (Ras1). We demonstrate that the role of Ras1 in Draf activation is not limited to the translocation of Draf to the membrane through a Ras1-Draf association. In addition, Ras1 is essential for the activation of an additional factor which in turn activates Draf.
Li
W
W
Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Melnick
M
M
Perrimon
N
N
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004789:Enzyme Activation; D005786:Gene Expression Regulation / Q000235:genetics*; D017403:In Situ Hybridization; D008845:Microinjections; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D019908:Proto-Oncogene Proteins c-raf / Q000235:genetics / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism*; D012333:RNA, Messenger; D012097:Repressor Proteins / Q000235:genetics
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C074090:TLL protein, Drosophila; D019908:Proto-Oncogene Proteins c-raf; D016283:Proto-Oncogene Proteins p21(ras)