Haspin kinase regulates microtubule-organizing center clustering and stability through Aurora kinase C in mouse oocytes

Meiotic oocytes lack classic centrosomes and therefore, bipolar spindle assembly depends on clustering of acentriolar microtubule-organizing centers (MTOCs) into two poles. However, the molecular mechanism regulating MTOCs assembly into two poles is not fully understood. Haspin kinase is required to regulate Aurora kinase C (AURKC) localization at chromosomes during meiosis I (MI). Here we show that inhibition of haspin perturbed MTOC clustering into two poles, and the stability of the clustered MTOCs. Furthermore, we show that AURKC localizes to MTOCs in mouse oocytes. Inhibition of haspin perturbed the localization of AURKC at MTOCs, and overexpression of AURKC rescued the MTOC clustering defects in haspin-inhibited oocytes. Taken together, our data uncover a role for haspin as a regulator of bipolar spindle assembly by regulating AURKC localized-function at acentriolar MTOCs in oocytes.