InterPro domain: IPR033871

The eukaryotic like-Sm (LSm) proteins assemble into a hetero-heptameric rings (LSm2-8 or LSm1-7) around a wide spectrum of RNAs. The LSm2-8 ring functions during general RNA maturation in the nucleus, while the LSm1-7 ring functions during mRNA degradation in the cytoplasm [ 1 , 2 ]. LSm2-8 form the core of the U6 snRNP particle that, in turn, assembles with other components to form the spliceosome which is responsible for the excision of introns and the ligation of exons [ 3 , 4 ]. The LSm1-7 ring is involved in recognition of the 3' uridylation tag and recruitment of the decapping machinery [ 5 , 6 ].

Members of the LSm family share a highly conserved Sm fold containing an N-terminal helix followed by a strongly bent five-stranded antiparallel beta-sheet [ 7 ].

This entry represents LSm5.

1. A Sm-like protein complex that participates in mRNA degradation. EMBO J. 19, 1661-71
2. Functions of Lsm proteins in mRNA degradation and splicing. Curr. Opin. Cell Biol. 12, 346-50
3. A doughnut-shaped heteromer of human Sm-like proteins binds to the 3'-end of U6 snRNA, thereby facilitating U4/U6 duplex formation in vitro. EMBO J. 18, 5789-802
4. Crystal structures of the Lsm complex bound to the 3' end sequence of U6 small nuclear RNA. Nature 506, 116-20
5. 3' Uridylation and the regulation of RNA function in the cytoplasm. Biochem. Soc. Trans. 38, 1150-3
6. Yeast Sm-like proteins function in mRNA decapping and decay. Nature 404, 515-8
7. LSm proteins form heptameric rings that bind to RNA via repeating motifs. Trends Biochem. Sci. 30, 522-8