Involved in modulating alternative pre-mRNA splicing with either 5' distal site activation or preferential use of 3' proximal site. In case of infection by Herpes simplex virus (HSVI), may act as a splicing inhibitor of HSVI pre-mRNA. {ECO:0000269|PubMed:19582790}.
AIP4 is phosphorylated by CISK in vitro on WW domain residues, which may impact its ability to interact with and ubiquitinate substrate proteins.|Expression of a constitutively active CISK inhibits CXCR4 degradation, possibly by attenuating CXCR4 binding to and ubiquitination by AIP4 and/or modulating the action of AIP4 on a protein involved in CXCR4 endosomal sorting .