Splicing factor 1, helix-hairpin domain (IPR032570)

Short name: SF1-HH

Overlapping homologous superfamilies


Domain relationships



This helix-hairpin domain can be found in N-terminal region of mammalian splicing factor 1 (SF1) and fungal branchpoint binding proteins (BBP) [PMID: 9433137]. These proteins are required for pre-spliceosome formation, which is the first step of pre-mRNA splicing [PMID: 12374752, PMID: 10775271].

SF1 forms a complex with U2AF65 through the interaction between this domain and the C-terminal U2AF homology motif domain (UHM) of U2AF65. This domain forms a secondary, hydrophobic interface with U2AF65(UHM) to lock the orientation of the two subunits, which is essential for cooperative formation of the ternary SF1-U2AF65-RNA complex [PMID: 23175611]. This domain contains a highly conserved SPSP motif at its C terminus; the phophorylation of the SPSP motif induces a disorder-to-order transition within a novel SF1/U2AF65 interface [PMID: 23273425].

Contributing signatures

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