Small nuclear ribonucleoprotein Sm D3 (IPR034099)

Short name: SmD3

Overlapping homologous superfamilies

Family relationships


This entry represents small nuclear ribonucleoprotein Sm D3.

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 [PMID: 10369684, PMID: 11259661, PMID: 11226169]. 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: 10025403].

Sm subunit D3 heterodimerizes with subunit B and three such heterodimers form a hexameric ring structure with alternating B and D3 subunits. The D3 - B heterodimer also assembles into a heptameric ring containing D1, D2, 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

GO:0005681 spliceosomal complex

Contributing signatures

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