Involved in pre-mRNA splicing as a component of the spliceosome (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. The WD repeats assemble into a seven-bladed WD propeller. Belongs to the WD repeat SMU1 family.