Ras isoform-specific signaling: location, location, location.

The proteins that compose the Ras family of small guanosine triphosphatases share a remarkably high degree of sequence similarity, yet recent evidence indicates that they may have unique biological properties. How is it that similar proteins carry out different jobs in the cell? Wolfman addresses this question by surveying recent reports that indicate that different biological roles may be born out of distinct subcellular localizations of the Ras proteins. It appears that the small differences in their amino acid sequences and their different posttranslational modifications may be all that is necessary to direct various Ras proteins to different sites.