Regional and Temporal Population Structure of Pseudoperonospora cubensis in Michigan and Ontario.

Cucurbit downy mildew (CDM), caused by the oomycete pathogen Pseudoperonospora cubensis, is a devastating disease that affects cucurbit species worldwide. This obligate, wind-dispersed pathogen does not overwinter in Michigan or other northern regions and new isolates can enter the state throughout the growing season. To evaluate the regional and temporal population structure of P.

The N terminus of Saccharomyces cerevisiae Sst2p plays an RGS-domain-independent, Mpt5p-dependent role in recovery from pheromone arrest.

The Saccharomyces cerevisiae RGS protein Sst2p is involved in desensitization to pheromone and acts as a GTPase-activating protein for the Galpha subunit Gpa1p. Other results indicate that Sst2p acts through Mpt5p and that this action occurs downstream of Fus3p and through Cln3p/Cdc28p. Our results indicate that the interaction of Sst2p with Mpt5p requires the N-terminal MPI (Mpt5p-interacting) domain of Sst2p and is independent of the C-terminal RGS domain.

Delineation of functional regions within the subunits of the Saccharomyces cerevisiae cell adhesion molecule a-agglutinin.

a-Agglutinin from Saccharomyces cerevisiae is a cell adhesion glycoprotein expressed on the surface of cells of a mating type and consists of an anchorage subunit Aga1p and a receptor binding subunit Aga2p. Cell wall attachment of Aga2p is mediated through two disulfide bonds to Aga1p (Cappellaro, C., Baldermann, C.

Multiple sex pheromones and receptors of a mushroom-producing fungus elicit mating in yeast.

The mushroom-producing fungus Schizophyllum commune has thousands of mating types defined, in part, by numerous lipopeptide pheromones and their G protein-linked receptors. Compatible combinations of pheromones and receptors encoded by different mating types regulate a pathway of sexual development leading to mushroom formation and meiosis. A complex set of pheromone-receptor interactions maximizes the likelihood of outbreeding; for example, a single pheromone can activate more than one receptor and a single receptor can be activated by more than one pheromone.

Switch-domain mutations in the Saccharomyces cerevisiae G protein alpha-subunit Gpa1p identify a receptor subtype-biased mating defect.

The response to pheromone in Saccharomyces cerevisiae involves a heterotrimeric G protein composed of Gpa1p (alpha subunit), Ste4p (beta) and Ste18p (gamma). The switch II region of G alpha subunits is involved in several protein-protein interactions and an intrinsic GTPase activity. To investigate the role of this region of Gpa1p, we have analyzed the effect of switch II mutations.