Small nuclear ribonucleoprotein D1 (IPR034102)

Short name: Sm_D1

Overlapping homologous superfamilies

Domain relationships


The eukaryotic Sm proteins (B/B', D1, D2, D3, E, F and G) assemble into a hetero-heptameric ring around the Sm site of the 2,2,7-trimethyl guanosine (m3G) capped U1, U2, U4 and U5 snRNAs (Sm snRNAs) forming the core of the snRNP particle. The snRNP particle, in turn, assembles with other components onto the pre-mRNA to form the spliceosome which is responsible for the excision of introns and the ligation of exons. Members of this family share a highly conserved Sm fold containing an N-terminal helix followed by a strongly bent five-stranded antiparallel beta-sheet [PMID: 10369684, PMID: 11259661, PMID: 11226169].

Sm subunit D1 heterodimerizes with subunit D2 and three such heterodimers form a hexameric ring structure with alternating D1 and D2 subunits. The D1 - D2 heterodimer also assembles into a heptameric ring containing DB, D3, E, F, and G subunits [PMID: 18984161, PMID: 23333303].

GO terms

Biological Process

GO:0000387 spliceosomal snRNP assembly

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.