Sm-like protein Lsm4 (IPR034101)
Short name: Lsm4
Overlapping homologous superfamilies
- LSM domain superfamily (IPR010920)
- LSM domain, eukaryotic/archaea-type (IPR001163)
- Sm-like protein Lsm4 (IPR034101)
This entry represents Sm-like protein Lsm4. It could be found in the nuclear Lsm2-8 complex or in the cytoplasmic Lsm1-7 complex.
The Lsm2-8 complex associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 snRNP, U4/U6.U5 snRNP, and free U6 snRNP). It binds and stabilizes the 3'-terminal poly(U) tract of U6 snRNA and facilitates the assembly of U4-U6 di-snRNP and U4-U6-U5 tri-snRNP [PMID: 22615807, PMID: 15916535, PMID: 24240276]. The Lsm1-7 complex associates with deadenylated mRNA and promotes decapping in the 5'-3' mRNA decay pathway [PMID: 22615807, PMID: 10801455].
The Sm and the Lsm proteins, characterised by the Sm-domain, have RNA-related functions. The Sm heptamer ring associates with four (U1, U2, U4, U5) snRNPs, while Lsm2-8 heptamer associates with the U6 snRNP. Another Lsm heptameric complex, Lsm1-7, which differs from Lsm2-8 by one Lsm protein, functions in mRNA decapping, a crucial step in the mRNA degradation pathway [PMID: 24513854].
- cd01723 (LSm4)