The goal of this proposal is to determine how the yeast """"""""two-component"""""""" regulator, Sln1p, controls the activity of the essential transcription factor Mcm1p. Sln1p has been characterized as the sensor-transmitter responsible for initial transduction of the osmotic stress signal through the Hog1p MAP kinase cascade. The authors have found that, additionally, Sln1p controls the activity of Mcm1p: activated sln1* mutations stimulate expression of the Mcm1p dependent reporter gene P-lacZ. Furthermore, regulation of Hog1p and Mcm1p define a branch point in the regulation conferred by Sln1p: both pathways were found to rely on Sln1p and the phosphorelay intermediate Ypd1p, but the signal diverges with the identity of the receiver molecule. Ssk1p is the receiver molecule for the Hog1p pathway and does not contribute to regulation of Mcm1p, whereas recent results from Dr. Fassler suggest that Skn7p is the likely receiver for the Mcm1p pathway. Accordingly, mutations in the downstream components of the Hog1p MAP kinase cascade have no effect on Mcm1p activity. Phenotypic analysis of the sln1* mutants reveals osmotic sensitivity indicating that the Hog1p and Mcm1p branches are reciprocally controlled by Sln1p phoshphorylation (increased phosphorylation results in concomitant osmotic sensitivity due to decreased signaling of Hog1p and increased Mcm1p activity). The authors intend to continue their analyses by: identifying and characterizing the factors mediating Sln1p control of Mcm1p; characterizing the biochemistry of Sln1p mediated signaling to Mcm1p; and characterizing the regions of Mcm1p required for response to the Sln1p signal.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM056719-02
Application #
2857318
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Anderson, James J
Project Start
1998-01-01
Project End
2001-12-31
Budget Start
1999-01-01
Budget End
1999-12-31
Support Year
2
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Iowa
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Fassler, Jan S; West, Ann H (2013) Histidine phosphotransfer proteins in fungal two-component signal transduction pathways. Eukaryot Cell 12:1052-60
Fassler, Jan S; West, Ann H (2011) Fungal Skn7 stress responses and their relationship to virulence. Eukaryot Cell 10:156-67
Mulford, K E; Fassler, J S (2011) Association of the Skn7 and Yap1 transcription factors in the Saccharomyces cerevisiae oxidative stress response. Eukaryot Cell 10:761-9
Fassler, Jan S; West, Ann H (2010) Genetic and biochemical analysis of the SLN1 pathway in Saccharomyces cerevisiae. Methods Enzymol 471:291-317
He, Xin-Jian; Mulford, KariAn E; Fassler, Jan S (2009) Oxidative stress function of the Saccharomyces cerevisiae Skn7 receiver domain. Eukaryot Cell 8:768-78
Shankarnarayan, Sandhya; Narang, Sandhya S; Malone, Cheryl L et al. (2008) Modulation of yeast Sln1 kinase activity by the CCW12 cell wall protein. J Biol Chem 283:1962-73
He, Xin-Jian; Fassler, Jan S (2005) Identification of novel Yap1p and Skn7p binding sites involved in the oxidative stress response of Saccharomyces cerevisiae. Mol Microbiol 58:1454-67
Lu, Jade Mei-Yeh; Deschenes, Robert J; Fassler, Jan S (2004) Role for the Ran binding protein, Mog1p, in Saccharomyces cerevisiae SLN1-SKN7 signal transduction. Eukaryot Cell 3:1544-56
Lu, Jade Mei-Yeh; Deschenes, Robert J; Fassler, Jan S (2003) Saccharomyces cerevisiae histidine phosphotransferase Ypd1p shuttles between the nucleus and cytoplasm for SLN1-dependent phosphorylation of Ssk1p and Skn7p. Eukaryot Cell 2:1304-14
Tao, Wei; Malone, Cheryl L; Ault, Addison D et al. (2002) A cytoplasmic coiled-coil domain is required for histidine kinase activity of the yeast osmosensor, SLN1. Mol Microbiol 43:459-73

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