Lsm2

LSM2 is a protein encoded by the LSM2 gene in eukaryotes. It is a member of the LSm family of small nuclear ribonucleoproteins, a group of highly conserved RNA-binding proteins that assemble into hexameric or heptameric rings to regulate RNA metabolism.

In most animals, plants, and fungi, LSM2 participates in two major RNA-processing complexes. The cytoplasmic Lsm1-7 complex includes LSM2 and promotes the decay of deadenylated mRNAs by facilitating decapping and subsequent exonucleolytic decay. In the nucleus, LSM2 participates in the Lsm2-8 assembly, a seven-subunit ring that binds U6 small nuclear RNA. This nuclear complex stabilizes U6 snRNA, contributes to U6 snRNP biogenesis, and supports pre-mRNA splicing and possibly other nuclear RNA processing pathways.

LSM2 is broadly expressed and, in many species, essential for normal RNA metabolism. Its function is largely determined by its participation in the respective LSm rings, and disruption can affect splicing efficiency and mRNA turnover. The LSM2 gene is conserved across eukaryotes, with orthologs identified in model organisms such as yeast, drosophila, and mammals, reflecting its central role in RNA biology.

Interactions: LSM2 forms heteromeric rings with other LSm proteins, and binds RNA as part of the complex rather than directly. Related proteins include LSM1, LSM3, LSM4, LSM5, LSM6, and LSM7 (in Lsm1-7) and LSM8 (in Lsm2-8).