The amino-terminal B-Raf-specific region mediates calcium-dependent homo- and hetero-dimerization of Raf.

ABSTRACT: B-Raf is a key regulatory molecule of the mitogen-activated protein kinase kinase (MEK). B-Raf differs from the other Raf isoforms in that it has a long amino-terminal region. By the use of probes based on the principle of fluorescence resonance energy transfer, we found that this amino-terminal B-Raf-specific region is essential for homo-dimerization of B-Raf and hetero-dimerization of B-Raf and c-Raf at the plasma membrane, followed by phosphorylation of Thr118 in the amino-terminal B-Raf-specific region. HeLa cells expressing B-Raf, but not c-Raf, or a B-Raf mutant lacking the B-Raf-specific region, showed enhanced MEK phosphorylation upon stimulation with a calcium agonist. Furthermore, increases in the intracellular calcium concentration were found to be necessary for dimerization and

SUBMITTER: Terai K 

PROVIDER: S-EPMC1538552 | biostudies-literature | 2006 Aug

REPOSITORIES: biostudies-literature