Participates in pre-mRNA U12-dependent splicing, performed by the minor spliceosome which removes U12-type introns. U12-type introns comprises less than 1% of all non-coding sequences. Binds to the 3'-stem-loop of m(7)G-capped U12 snRNA (By similarity). Component of the U11/U12 snRNPs that are part of the U12-type spliceosome. Found in a complex with m(7)G-capped U12 snRNA. Interacts with PDCD7 (By similarity).