. "Authored: Charalambous, M, 2005-01-07 11:17:43"^^ . "Edited: Schmidt, EE, 0000-00-00 00:00:00"^^ . "Reviewed: Heldin, CH, 2008-02-12 09:44:02"^^ . "Activated p21ras (the GTP-bound form) is associated with the plasma membrane. Inactive Raf-1 is associated in the cytoplasm with 14-3-3. 14-3-3 binds to Raf-1 via the Ser259 phosphorylation site (S1). This interaction stabilises the inactive conformation of Raf-1 in which the Ras-binding Cysteine-rich domain (CRD) is obscured. The Raf-1 molecule contains an additional p21ras-binding domain (RBD), a second serine phosphorylation site at S621 (S2) and two tyrosine phosphorylation sites (at 340, Y1 and 341, Y2).
Raf-1 binds activated p21ras via the RBD. This displaces 14-3-3 from Ser259 and unmasks the CRD."^^ . . . . . . "Transient dissociation of 14-3-3 upon Ras binding"^^ . . . . .