Post-translational modifications local effects

The proto-oncogene ra/becomes active in response to ras stimulation. However, the mechanisms through which ras accomplishes this are only partially understood. Ras requires post-translational modification (farnesylation) to effect cellular transformation and the activation of the enzymes, raf and MAPK (Itoh et al, 1993). It appears that ras functions primarily to localize raf to the surface membrane, where additional factors are involved in the subsequent activation of raf... 

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