Involved in pre-mRNA splicing as component of the activated spliceosome. As a component of the minor spliceosome, involved in the splicing of U12-type introns in pre-mRNAs (Probable). {ECO:0000269|PubMed:29360106, ECO:0000269|PubMed:29361316, ECO:0000305|PubMed:33509932}. This is the function of RBMX2 (RNA binding motif protein X-linked 2, Ensembl gene identifier ENSG00000134597).