LSM8

LSm8 is a protein encoded by the LSM8 gene and is a member of the LSm family of Sm-like proteins found in eukaryotes. It is one of seven proteins in the nuclear LSm2-8 complex and is highly conserved across species, indicating an essential role in RNA metabolism.

In the nucleus, LSm8 participates in the assembly and stability of the U6 small nuclear RNA (snRNA) by forming a heteroheptameric ring with LSm2–LSm7. The LSm2-8 complex binds the 3' end of U6 snRNA and protects it from degradation, supporting the biogenesis and recycling of U6 within the spliceosome. Through its association with U6 snRNA, LSm8 contributes to the formation of the U6 snRNP, a core component of the spliceosome required for pre-mRNA splicing.

Structurally, LSm8 contains an Sm-like domain that participates in forming the circular protein ring characteristic of LSm complexes. The complex typically localizes to the nucleus, consistent with its role in U6 snRNA processing, though dynamic shuttling with the cytoplasm has been observed for some LSm proteins.

Functional studies in model organisms have highlighted the importance of LSm8 for proper RNA maturation and stability, with defects in LSm components linked to altered RNA metabolism. LSm8 interacts with other LSm components and snRNP factors as part of the larger spliceosomal assembly pathway.