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Perspectives
Spatial Segregation of Ras Signaling—New Evidence from Fission Yeast
Eric C. Chang and Mark R. Philips
volume 5 | issue 17
1 september 2006Pages: 1936 - 1939
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The Ras GTPases act as binary switches for signal transduction pathways that are important for growth regulation and tumorigenesis. Despite the biochemical simplicity of this switch, Ras proteins control multiple pathways, and the functions of the four mammalian Ras proteins are not overlapping. This raises an important question—how does a Ras protein selectively regulate a particular activity? One recently emerging model suggests that a single Ras protein can control different functions by acting in distinct cellular compartments. A critical test of this model is to identify pathways that are selectively controlled by Ras when it is localized to a particular compartment. A recent study has examined Ras signaling in the fission yeast Schizosaccharomyces pombe, which expresses only one Ras protein that controls two separate evolutionarily conserved pathways. This study demonstrates that whereas Ras localized to the plasma membrane selectively regulates a MAP kinase pathway to mediate mating pheromone signaling, Ras localized to the endomembrane activates a Cdc42 pathway to mediate cell polarity and protein trafficking. This study has provided unambiguous evidence for compartmentalized signaling of Ras.
We now provide open access to journal articles published online for one year or more. This article may be downloaded at the following link:
Download PDF If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.