Poster abstracts

Poster number 22 submitted by Wenfang Liu

Determining the Relationship Between P-bodies and Tubulin Proteostasis

Wenfang Liu (MCDB program), Zachary Hurst (The Ohio State University), Shi Qian (MCDB program)

Abstract:
Processing-bodies (P-bodies) are subcellular ribonucleoprotein (RNP) granules that contain translationally-repressed mRNAs as well as proteins involved in mRNA decay. P-bodies are conserved from yeast to mammals and have been suggested to be sites of mRNA degradation and/or storage. These RNP granules are dynamic structures that form in response to a variety of stress conditions. We are interested in developing a better understanding of the regulation of P-body assembly and defining the physiological roles of these RNP granules. Towards these ends, we have identified a role for the heterohexameric chaperone complex, known as prefoldin, in P-body assembly. Specifically, we have found that the loss of prefoldin activity results in elevated P-body formation in both wild-type cells and a mutant that is normally defective for P-body assembly. Moreover, our data indicate that these effects are due to the defective folding of tubulin monomers and the ultimate disruption of the microtubule networks in the cell. As a result, we have proposed that there is a relationship between P-body assembly and tubulin proteostasis in eukaryotic cells.
Our current efforts are focused on characterizing these novel P-body-like foci and the underlying reasons that they are induced by microtubule disruption. Interestingly, these granules appear to differ from traditional P-bodies in several significant ways, including by granule morphology and overall protein composition. For example, we have found that several core P-body constituents are absent from these granules whereas tubulin monomers are present specifically in these structures. These differences as well as potential models to explain the physiological significance of these novel structures will be discussed herein.

References:
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Keywords: RNP granules, P-bodies, tubulin proteostasis