Poster abstracts

Poster number 83 submitted by Khyati Shah

The cAMP-Dependent Protein Kinase Signaling Pathway Is a Key Regulator of P-Body Foci Formation

Khyati H. Shah (Dept. of Molecular Genetics, The Ohio State University), Vidhya Ramachandran (Dept. of Molecular Genetics, The Ohio State University), Paul K. Herman (Dept. of Molecular Genetics, The Ohio State University)

Abstract:
In response to stress, eukaryotic cells accumulate mRNAs and proteins at discrete sites, or foci, in the cytoplasm. However, the mechanisms regulating foci formation, and the biological function of the larger ribonucleoprotein (RNP) assemblies, remain poorly understood. In this study, we examined the signaling requirements for P body formation in response to glucose deprivation in S. cerevisiae. Here, we show that the cAMP-dependent protein kinase (PKA) in Saccharomyces cerevisiae is a key regulator of the assembly of processing bodies (P bodies), an RNP complex implicated in mRNA processing and translation. Biochemical analysis and fluorescence microscopy suggest that PKA specifically inhibits the formation of the larger P body aggregates by directly phosphorylating Pat1, a conserved constituent of these foci that functions as a scaffold during the assembly process. PKA can regulate the formation of these foci under varied stresses like hyperosmotic stress, glucose starvation, oxidative stress etc. Moreover, recent data shows that PKA has no role in the assembly of stress granules, suggesting that the regulation of these foci in the cells is fundamentally different. Finally, we present evidence indicating that P body foci are required for the long-term survival of stationary phase cells. This work therefore highlights the general relevance of RNP foci in quiescent cells, and provides a framework for the study of the many RNP assemblies that form in eukaryotic cells. This work was supported by a grant from the National Institutes of Health (GM65227)

References:
Mol Cell. 2011 Sep 16;43(6):973-81.
The cAMP-dependent protein kinase signaling pathway is a key regulator of P body foci formation.
Ramachandran V, Shah KH, Herman PK.

Keywords: P-bodies, Protein Kinase A, Stress Granules