OBJECTIVES:
The long-term goal of the Miller lab is to understand how signal transduction circuits control microtubules so that effective and targeted interventions can be developed to manipulate microtubule functions in stressful situations like disease and space travel. The Miller lab recently established that the microtubule-associated protein Stu2p interacts with SUMO. Preliminary data from the Miller lab suggest that there are two modes of interaction between Stu2p and SUMO: a covalent interaction in which Stu2p is conjugated by SUMO and a non-covalent interaction in which Stu2p simply binds to SUMO. The objective of this work is to identify novel signal transduction mechanisms that regulate cytoskeletal networks in response to simulated microgravity conditions. The rationale is that by achieving a fuller understanding of the regulation of cytoskeletal polymers under simulated microgravity conditions on Earth, researchers can develop more complete hypotheses of how the cytoskeleton responds to gravitational changes in the space environment, which can be tested in future space missions. This knowledge may be used to design interventions for adverse health effects that are associated with space travel. The specific goal of this proposal is to determine how simulated microgravity alters the interaction of SUMO with the cellular proteome, and microtubule-associated proteins (MAPS) in particular. The central hypothesis of this work is that microgravity alters the post-translational modifications of lysine residues of a wide variety of cytoskeletal proteins. To test this hypothesis, the post-translational modifications on lysines residues will be analyzed on a proteome-wide basis by mass-spectrometry and immunoblotting under simulated microgravity conditions. We will also test whether the proteome binds differentially to SUMO when it experiences microgravity. An additional emphasis will be placed on the MAP Stu2p.

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