LSM7s

LSM7 is a member of the LSM family of Sm-like proteins that are essential for RNA metabolism in eukaryotic cells. In humans and other organisms, LSM7 is a component of two major heptameric rings that carry out distinct roles in RNA processing: the cytoplasmic LSM1-7 complex and the nuclear LSM2-8 complex. The cytoplasmic complex participates in mRNA decay by promoting decapping of deadenylated transcripts, thereby facilitating 5' to 3' exonucleolytic degradation. The nuclear complex associates with U6 small nuclear RNA and supports pre-mRNA splicing and other RNA processing events. Through these roles, LSM7 contributes to the regulation of gene expression at both transcriptional and post-transcriptional levels.

Structurally, LSM7 forms part of a circular Sm-like ring with other LSM proteins, stabilizing RNA and influencing its fate. The proteins in this family share the Sm motif and assemble into heteromeric rings that are conserved across eukaryotes, underscoring their fundamental importance. LSM7 is broadly expressed and conserved, reflecting its essential function in RNA metabolism.

Regulation of LSM7 expression and activity is coordinated with cellular state and stress conditions. Alterations in the expression or function of LSM family members have been observed in various cancers and neurological conditions, though the specific contributions of LSM7 require further study. In model systems, disruption of LSM7 or the LSM1-7 and LSM2-8 complexes leads to defects in mRNA decay and splicing, illustrating the critical role of LSM7 in maintaining proper gene expression.

See also: LSM1-7 complex, LSM2-8 complex, mRNA decay, splicing.