Part of pre- and post-splicing multiprotein mRNP complexes. Auxiliary component of the splicing-dependent multiprotein exonjunction complex (EJC) deposited at splice junction on mRNAs. The EJCis a dynamic structure consisting of core proteins and severalperipheral nuclear and cytoplasmic associated factors that join thecomplex only transiently either during EJC assembly or duringsubsequent mRNA metabolism. Component of the ASAP and PSAP complexeswhich bind RNA in a sequence-independent manner and are proposed to berecruited to the EJC prior to or during the splicing process and toregulate specific excision of introns in specific transcriptionsubsets. The ASAP complex can inhibit RNA processing during in vitrosplicing reactions. The ASAP complex promotes apoptosis and isdisassembled after induction of apoptosis. Enhances the formation ofthe ATP-dependent A complex of the spliceosome. Involved in bothconstitutive splicing and, in association with SRP54 and TRA2B/SFRS10, in distinctive modulation of alternative splicing in a substrate-dependent manner. Involved in the splicing modulation of BCL2L1/Bcl-X (and probably other apoptotic genes); specifically inhibits formationof proapoptotic isoforms such as Bcl-X (S); the activity is differentfrom the established EJC assembly and function. Participates in mRNA3'-end cleavage. Involved in UPF2-dependent nonsense-mediated decay (NMD) of mRNAs containing premature stop codons. Also mediates increaseof mRNA abundance and translational efficiency. Binds spliced mRNA 20-25 nt upstream of exon-exon junctions. [1-10]

MDLSGVKKKSLLGVKENNKKSSTRAPSPTKRKDRSDEKSKDRSKDKGATKESSEKDRGRDKTRKRRSASSGSSSTRSRSSSTSSSGSSTSTGSSSGSSSSSASSRSGSSSTSRSSSSSSSSGSPSPSRRRHDNRRRSRSKSKPPKRDEKERKRRSPSPKPTKVHIGRLTRNVTKDHIMEIFSTYGKIKMIDMPVERMHPHLSKGYAYVEFENPDEAEKALKHMDGGQIDGQEITATAVLAPWPRPPPRRFSPPRRMLPPPPMWRRSPPRMRRRSRSPRRRSPVRRRSRSPGRRRHRSRSSSNSSR