Involved in pre-mRNA splicing as a component of the splicing factor SF3A complex that contributes to the assembly of the 17S U2 snRNP, and the subsequent assembly of the pre-spliceosome 'E' complex and the pre-catalytic spliceosome 'A' complex (PubMed:10882114, PubMed:11533230). Involved in pre-mRNA splicing as a component of pre-catalytic spliceosome 'B' complexes, including the Bact complex (PubMed:29361316, PubMed:29360106, PubMed:30315277). Interacts directly with the duplex formed by U2 snRNA and the intron (PubMed:29360106). Component of splicing factor SF3A which is composed of three subunits; SF3A3/SAP61, SF3A2/SAP62 and SF3A1/SAP114 (PubMed:10882114, PubMed:11533230, PubMed:21349847). SF3A1 functions as scaffold that interacts directly with both SF3A2 and SF3A3 (PubMed:11533230, PubMed:21349847). SF3A associates with the splicing factor SF3B and a 12S RNA unit to form the mature 17S U2 small nuclear ribonucleoprotein complex (17S U2 snRNP) (PubMed:10882114, PubMed:11533230). Identified in the spliceosome 'E' complex, a precursor of the spliceosome 'A' complex (PubMed:10882114). Identified in the spliceosome 'A' and 'B' complexes (PubMed:10882114, PubMed:29361316, PubMed:29360106, PubMed:30315277). Identified in the spliceosome 'C' complex (PubMed:11991638). Interacts with HTATSF1 (PubMed:9710584). Belongs to the SF3A2 family.