Lsm proteins and RNA processing¹

Sm and Lsm proteins are ubiquitous in eukaryotes and form complexes that interact with RNAs involved in almost every cellular process. My laboratory has studied the Lsm proteins in the yeast Saccharomyces cerevisiae, identifying in the nucleus and cytoplasm distinct complexes that affect pre-mRNA splicing and degradation, small nucleolar RNA, tRNA processing, rRNA processing and mRNA degradation. These activities suggest RNA chaperone-like roles for Lsm proteins, affecting RNA–RNA and/or RNA–protein interactions. This article reviews the properties of the Sm and Lsm proteins and structurally and functionally related proteins in archaea and eubacteria.