title: Compartmentalized signaling of Ras in fission yeast.
abstract: Compartment-specific Ras signaling is an emerging paradigm that may explain the multiplex outputs from a single GTPase. The fission yeast, Schizosaccharomyces pombe, affords a simple system in which to study Ras signaling because it has a single Ras protein, Ras1, that regulates two distinct pathways: one that controls mating through a Byr2-mitogen-activated protein kinase cascade and one that signals through Scd1-Cdc42 to maintain elongated cell morphology. We generated Ras1 mutants that are restricted to either the endomembrane or the plasma membrane. Protein binding studies showed that each could interact with the effectors of both pathways. However, when examined in ras1 null cells, endomembrane-restricted Ras1 supported morphology but not mating, and, conversely, plasma membrane-restricted Ras1 supported mating but did not signal to Scd1-Cdc42. These observations provide a striking demonstration of compartment-specific Ras signaling and indicate that spatial specificity in the Ras pathway is evolutionarily conserved.
authors.affiliation: Department of Molecular and Cell Biology, The Breast Center, Baylor College of Medicine, 1 Baylor Plaza, BCM 600, Houston, TX 77030, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Onken
authors.forename: Heidi
authors.initials: H
authors.lastname: Wiener
authors.forename: Mark R
authors.initials: MR
authors.lastname: Philips
authors.forename: Eric C
authors.initials: EC
authors.lastname: Chang
mesh_terms: D000818:Animals; D002460:Cell Line; D048430:Cell Shape; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C089769:scd1 protein, S pombe; C077892:BYR2 protein, S pombe; D020930:MAP Kinase Kinase Kinases; C492657:Ras1 protein, S pombe; D018631:ras Proteins