LSM5

LSM5 is a gene that encodes the LSM5 protein, a member of the Sm-like (LSM) family of RNA-binding proteins in eukaryotes. LSM5 is highly conserved across eukaryotes and functions as a core component of two major LSM complexes involved in RNA metabolism: the cytoplasmic LSM1-7 complex and the nuclear LSM2-8 complex.

In the cytoplasm, LSM5 participates in mRNA decay by contributing to the function of the LSM1-7 complex, which binds deadenylated mRNAs and promotes decapping and 5' to 3' degradation. In the nucleus, LSM5 is part of the LSM2-8 complex that helps stabilize U6 snRNA and supports pre-mRNA splicing. Through these roles, LSM5 links RNA processing with RNA turnover, supporting proper gene expression.

Structure and localization: LSM proteins share an Sm-like domain and assemble into a heteromeric, ring-shaped complex. LSM5 is one of seven subunits in the LSM1-7 complex and is also present in the LSM2-8 complex, reflecting its involvement in both cytoplasmic and nuclear RNA pathways. The distribution of these complexes can vary with cellular conditions and developmental stage.

Biological significance: The dual involvement of LSM5 in mRNA decay and splicing makes it essential for normal RNA metabolism. Disruption of LSM5 function in model systems leads to defects in RNA processing and growth, underscoring the importance of the LSM network in cellular homeostasis.

Genetics and evolution: LSM5 homologs are found in yeast, plants, animals, and other eukaryotes, indicating an ancient and conserved role of LSM proteins in RNA biology.

See also: LSM, Sm-like proteins, LSM1-7, LSM2-8.