Exploring the role of low complexity protein sequence in regulating RNA granule dynamics and translation control

Abstract

RNA granules are conserved membraneless mRNP complexes that play an important role in determining mRNA fate by affecting translation repression and mRNA decay. Processing bodies (P-bodies) harbor enzymes responsible for mRNA decay and proteins involved in modulating translation. Although many proteins have been identified to play a role in P-body assembly, a bonafide disassembly factor remains unknown. We observed that Sbp1 with the help of its RGG-motif promotes P-body disassembly in S. cerevisiae. This study provides an example of the role of low complexity sequence in RNA granule disassembly. We have further explored the role of human RGG-motif containing proteins in regulation of translation. Here we studied LSM14A (human homolog of Scd6) in maintaining RNA granule dynamics and regulation of mRNA. We observe that LSM14A binds to human eIF4G and plays an important role in regulating the translation of certain mRNAs in response to genotoxic stress. Overall using a combination of yeast and human cell culture system, this study provides critical insight into the role of conserved low complexity sequences.