Like human cells, budding yeast (S. cerevisiae) contains multiple MAPK cascades. The mating pheromone response pathway (Fus3 MAPK), initiated by a GPCR, is arguably the best understood MAPK pathway in any eukaryote. Also well studied are the high-osmolarity glycerol (HOG) pathway for coping with hyperosmotic stress (Hog1 MAPK), the filamentous growth response triggered by nutrient limitation (Kss1 MAPK), and the cell wall integrity pathway that coordinates cell wall synthesis and repair with cell membrane expansion (Mpk1 MAPK). However, many basic questions remain about how such pathways are arranged to maintain specificity, how such pathways are integrated, and how they modulate the processes and behaviors under their control, especially changes in cell growth and polarity. The overall goal of this project is to use the experimental advantages of yeast to continue to examine fundamental properties of the organization, fidelity, regulation, and function of MAPK signaling pathways, as a means of undercovering additional new principles and processes generally applicable to the highly homologous MAPK pathways in human cells. MAPK- mediated signaling evokes an elaborate network of interlocking events, rather than a simple linear pathway;but, it is not well understood how changes in metabolism, gene expression, and biosynthesis (especially membrane lipid synthesis) are properly coordinated in space and time to achieve dramatic changes in cell morphology. Moreover, certain temporal and spatial aspects of MAPK signaling are imposed by negative feedback mechanisms, and others by the cell cycle machinery, but much more needs to be learned about signal propagation and the mechanisms that modulate the efficiency and duration of signaling events. In particular, pheromone response, filamentous growth, and the HOG pathway share the same MAPKKK (Ste11), but are coupled to different upstream inputs, elicit the appropriate response upon the correct stimulus, yet avoid adventitious activation of the wrong output. How different extracellular signals impinge on the same MAPK elements, yet are deciphered differently, is not fully understood in any organism. To address many of these issues experimentally, our specific aims and goals include: (1) mutational and structural analysis of DEP domain-mediated GPCR recognition;(2) genetic and biochemical studies of the mechanism of MAPK-induced anisotropy in plasma membrane phosphoinositide distribution;(3) genetic and biochemical studies of the control of the remodeling of other plasma membrane lipids in pheromone- and nutrient limitation-induced polarized growth;(4) biochemical and genetic analysis of the mechanism of MAPK-mediated control of the organization and dynamics of the septin filament cytoskeleton;and, (5) determination of the molecular basis by which the stress-activated Hog1 MAPK blocks inappropriate activation of the other two pathways (Fus3 MAPK and Kss1 MAPK) that utilize the same MAPKKK (Ste11).
This proposed project has substantial public health relevance because the growth of many human tumor cells can be traced to mutations that lead directly to inappropriate and persistent MAPK activation. Thus, further elucidation of the fundamental aspects of MAPK signaling may provide new insights for the development of novel and more effective anti-cancer therapies to ameliorate certain prevalent malignancies in people.
|Leskoske, Kristin L; Roelants, Françoise M; Emmerstorfer-Augustin, Anita et al. (2018) Phosphorylation by the stress-activated MAPK Slt2 down-regulates the yeast TOR complex 2. Genes Dev 32:1576-1590|
|Roelants, Françoise M; Chauhan, Neha; Muir, Alexander et al. (2018) TOR complex 2-regulated protein kinase Ypk1 controls sterol distribution by inhibiting StARkin domain-containing proteins located at plasma membrane-endoplasmic reticulum contact sites. Mol Biol Cell 29:2128-2136|
|Emmerstorfer-Augustin, Anita; Augustin, Christoph M; Shams, Shadi et al. (2018) Tracking yeast pheromone receptor Ste2 endocytosis using fluorogen-activating protein tagging. Mol Biol Cell 29:2720-2736|
|Roelants, Françoise M; Leskoske, Kristin L; Martinez Marshall, Maria Nieves et al. (2017) The TORC2-Dependent Signaling Network in the Yeast Saccharomyces cerevisiae. Biomolecules 7:|
|Leskoske, Kristin L; Roelants, Françoise M; Marshall, Maria Nieves Martinez et al. (2017) The Stress-Sensing TORC2 Complex Activates Yeast AGC-Family Protein Kinase Ypk1 at Multiple Novel Sites. Genetics 207:179-195|
|Roelants, Françoise M; Leskoske, Kristin L; Pedersen, Ross T A et al. (2017) TOR Complex 2-Regulated Protein Kinase Fpk1 Stimulates Endocytosis via Inhibition of Ark1/Prk1-Related Protein Kinase Akl1 in Saccharomyces cerevisiae. Mol Cell Biol 37:|
|Booth, E A; Thorner, J (2016) A FRET-based method for monitoring septin polymerization and binding of septin-associated proteins. Methods Cell Biol 136:35-56|
|Klionsky, Daniel J (see original citation for additional authors) (2016) Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition). Autophagy 12:1-222|
|Sen, Arpita; Acosta-Sampson, Ligia; Alvaro, Christopher G et al. (2016) Internalization of Heterologous Sugar Transporters by Endogenous ?-Arrestins in the Yeast Saccharomyces cerevisiae. Appl Environ Microbiol 82:7074-7085|
|Guerreiro, Joana F; Muir, Alexander; Ramachandran, Subramaniam et al. (2016) Sphingolipid biosynthesis upregulation by TOR complex 2-Ypk1 signaling during yeast adaptive response to acetic acid stress. Biochem J 473:4311-4325|
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