Small nuclear ribonucleoprotein Sm D3 (SNRPD3)

Plays role in pre-mRNA splicing as core component of this SMN-Sm complex that mediates spliceosomal snRNP assembly and as component 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:25555158, PubMed:26912367, PubMed:28502770, PubMed:28781166, PubMed:28076346). Component of the pre- catalytic spliceosome B complex and activated spliceosome C complexes (PubMed:11991638, PubMed:28502770, PubMed:28781166, PubMed:28076346).

Is also a component of the minor U12 spliceosome (PubMed:15146077). Included in the U7 snRNP it's involved in histone pre-mRNA 3'-end processing (By similarity).