Pat1 contains distinct functional domains that promote translational repression, P‐body assembly and activation of decapping

Abstract

The control of mRNA degradation and translation are important aspects of gene regulation. Recent results suggest that translation repression and mRNA decapping can be intertwined and involve the formation of a quiescent mRNP, which can accumulate in cytoplasmic foci referred to as P‐bodies. The Pat1 protein is a key component of this complex and an important activator of decapping yet little is known about its function. In this work we analyze Pat1 in Saccharomyces cerevisae function by deletion and functional analyses. Our results identify two primary functional domains in Pat1, one promotes translation repression and P‐body assembly, and a second domain promoting mRNA decapping after assembly of the mRNA into a P‐body mRNP. In addition, we provide evidence that Pat1 binds RNA and has numerous domain specific interactions with mRNA decapping factors. These results indicate that Pat1 is an RNA binding protein and a multi‐domain protein that functions at multiple stages in the process of translation repression and mRNA decapping. Current experiments are directed at understanding the mechanism by which Pat1 affects translation repression and possible roles for nuclear‐cytoplasmic shuttling of Pat1.NIH grant (R37 GM45443) and funds from the Howard Hughes Medical Institute supported this work.