Plays a role in mitotic bipolar spindle formation. Binds mRNA. May function in nucleocytoplasmic transport and in directly or indirectly attaching cytoplasmic mRNPs to the cytoskeleton. Interacts with NUMA1 (via N-terminal end of the coiled-coil domain); this interaction promotes spindle formation in mitosis (By similarity). Interacts with NUP98 (By similarity). Interacts with MYCBP2 (By similarity). Interacts with USP11 (By similarity). Recruited from interphase nuclei to spindle MTs during mitosis. Belongs to the WD repeat rae1 family.