Model for dual regulation of CENP-A assembly through HJURP and M18BP1.S interaction with the CENP-C cupin domain. In metaphase, the targeting of the HJURP/CENP-A/H4 complex to the centromere is inhibited by phosphorylation of HJURP^S220 preventing interaction with CENP-C. Phosphorylated M18BP1.S binds to the cupin domain of CENP-C providing a second inhibitory mechanism that prevents HJURP interaction in metaphase. Upon cycling into interphase, the inhibitory phosphorylation of HJURP^S220 is removed and M18BP1.S dissociates from the CENP-C cupin domain allowing HJURP targeting to centromeres and new CENP-A assembly.