CHFR binds to and regulates MAD2 in the spindle checkpoint through its cysteine-rich domain

► The tumor suppressor CHFR binds and regulates the spindle checkpoint protein MAD2. ► CHFR/MAD2 interaction is abolished by deletion of the cysteine-rich domain of CHFR. ► CHFRΔCys is unable to rescue the mislocalization of MAD2 in CHFR−/− MEFs. ► CHFRΔCys expression does not rescue the mitotic defect seen in CHFR−/− MEFs. ► MAD2/CDC20 interaction is reduced in CHFR−/− MEFs expressing CHFRΔCys.