Plays a role in pre-mRNA splicing as component of the U4/U6- U5 tri-snRNP complex that is involved in spliceosome assembly, and as component of the precatalytic spliceosome (spliceosome B complex) (PubMed:28781166). The heptameric LSM2-8 complex binds specifically to the 3'-terminal U-tract of U6 snRNA (PubMed:10523320). Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner, facilitating the efficient association of RNA processing factors with their substrates. Component of the cytoplasmic LSM1-LSM7 complex, which is thought to be involved in mRNA degradation by activating the decapping step in the 5'-to-3' mRNA decay pathway (Probable). {ECO:0000269|PubMed:10523320, ECO:0000269|PubMed:28781166, ECO:0000305|PubMed:12515382}. This is the function of Ensembl gene identifier ENSG00000164167 (LSM6, LSM6 homolog, U6 small nuclear RNA and mRNA degradation associated).