Raf1 interaction with Cdc25 phosphatase ties mitogenic signal transduction to cell cycle activation.
The Ras and Raf1 proto-oncogenes transduce extracellular signals that promote cell growth. Cdc25 phosphatases activate the cell division cycle by dephosphorylation of critical threonine and tyrosine residues within the cyclin-dependent kinases. We show here that Cdc25 phosphatase associates with raf1 in somatic mammalian cells and in meiotic frog oocytes. Furthermore, Cdc25 phosphatase can be activated in vitro in a Raf1-dependent manner. We suggest that activation of the cell cycle by the Ras/Raf1 pathways might be mediated in part by Cdc25.
Galaktionov
K
K
Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724, USA.
Jessus
C
C
Beach
D
D
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000032:analysis / Q000378:metabolism*; D002457:Cell Extracts; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry; D005347:Fibroblasts; D006367:HeLa Cells; D006801:Humans; D008540:Meiosis; D008969:Molecular Sequence Data; D009865:Oocytes; D010749:Phosphoprotein Phosphatases / Q000032:analysis / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D018411:Spodoptera; D014981:Xenopus; D020687:cdc25 Phosphatases
D018797:Cell Cycle Proteins; D002457:Cell Extracts; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D010749:Phosphoprotein Phosphatases; D020687:cdc25 Phosphatases