12167697 Reactions were immunoblotted as indicated. (B) The reactions were identical to those for panel A, except that recombinant WT-MEK1 activated by recombinant B-Raf in vitro was used to phosphorylate the immunoprecipitated ERKs.
12351703 V., Calleja V., Scimeca J.-C., Filloux C., Calothy G. and Van Obberghen E. (1995) Regulation of the MAP kinases cascade in PC12 cells: B-Raf activates MEK-1 (MAP kinase or ERK kinase) and is inhibited by cAMP.
15153095 In addition, MEK1/2 can be activated by B-Raf, a neuron-enriched isoform of Raf, which is in turn activated by a cAMP-responsive Ras homologue called Rap-1 [ 41 ].
14570902 The activated Ras and Rap1 stimulate sequential activation of Raf serine/threonine kinases C-Raf and B-Raf, respectively, which in turn activate MEK1/ERKs.
7559496 We also showed that B-Raf interacts in vivo with Mek-1 and phosphorylates this protein on both serine 218 and 222( 25 ) .
15572664 Activated B-Raf activates MEK1, which in turn phosphorylates and activates ERK1/2 for a sustained period.
8668348 We show that, consequently, B-Raf interacts with MEK-1 and MEK-2 with a better affinity than does c-Raf-1, thus strengthening the notion that B-Raf is a stronger MEK activator than c-Raf-l.
7731720 However, there has been no evidence for a direct interaction between B-Raf and Mek-1.
12218141 (CellType: neutrophil) This is consistent with other findings that C5a causes the activation of Raf-1 and B-Raf, which are upstream stimulators of MEK-1 in human neutrophils, with a peak of activation at 5 min, followed by suppressed activation thereafter ( 38 ).