U2 small nuclear ribonucleoprotein auxiliary factor 35 kDa subunit-related protein 2 (ZRSR2)

Pre-mRNA-binding protein required for splicing of both U2- and U12-type introns. Selectively interacts with the 3'-splice site of U2- and U12-type pre-mRNAs and promotes distinct steps in U2 and U12 intron splicing.

Recruited into U12 pre-mRNAs in an ATP- dependent manner and is required for assembly of the prespliceosome, a precursor to other spliceosomal complexes. For U2-type introns, it is selectively and specifically necessary for the next step of splicing.