Investigating the effect of SEMDJL2 mutations in chromokinesin KIF22 on phospho-regulation

Mutations in chromokinesin KIF22 are linked to a development disorder known as spondyloepimetaphyseal dysplasia with joint laxity type 2 (SEMDJL2). These mutations prevent KIF22 from inactivating during anaphase, leading to cell division abnormalities. However, how these mutations do so remains unknown. Using cell culture, fluorescence microscopy, and nuclear morphology quantification, we demonstrate that SEMDJL2 mutations are not preventing KIF22 from inactivating by interfering with dephosphorylation at phospho-regulatory regions, as cell division abnormalities are not rescued when these regions are constitutively dephosphorylated. Therefore, additional studies must be conducted investigating alternative mechanisms behind this KIF22 inactivation failure, such as disruptions to autoinhibition.