Small nuclear ribonucleoprotein Sm D1 (SNRPD1)

Plays role in pre-mRNA splicing as core part of the SMN-Sm complex that mediates spliceosomal snRNP assembly and as part of the spliceosomal U1, U2, U4 and U5 small nuclear ribonucleoproteins (snRNPs), the building blocks of the spliceosome (PubMed:11991638, PubMed:18984161, PubMed:19325628, PubMed:23333303, PubMed:25555158, PubMed:26912367, PubMed:28502770, PubMed:28781166, PubMed:28076346). Part of both the pre-catalytic spliceosome B complex and activated spliceosome C complexes (PubMed:11991638, PubMed:26912367, PubMed:28502770, PubMed:28781166, PubMed:28076346).

Is also a part of the minor U12 spliceosome (PubMed:15146077). May act as a charged protein scaffold to promote snRNP assembly or fortify snRNP-snRNP interactions through non-specific electrostatic contacts with RNA (Probable).