Involved in pre-mRNA splicing as a component of the spliceosome (By similarity). Regulates alternative splicing of the HSPG2 pre-mRNA (By similarity). Required for normal accumulation of IK (By similarity). Required for normal mitotic spindle assembly and normal progress through mitosis (By similarity). Component of the spliceosome B complex. Interacts with IK. Colocalizes with SRSF1 in nuclear speckles. At 10.5 dpc expressed in otic vesicle. The WD repeats assemble into a seven-bladed WD propeller. Belongs to the WD repeat SMU1 family.