A Moonlighting Function of Kinetochore Complex Proteins in Golgi Assembly of Neural Stem Cells

Kinetochores play an essential role in mitosis, and human kinetochore variants are associated with microcephaly. However, their functions in quiescent/interphase cells are unknown. Here, we demonstrate that Drosophila kinetochore proteins promote the reactivation of quiescent NSCs and their regeneration upon injury by organizing Golgi-dependent acentrosomal microtubules. Drosophila kinetochore proteins localize to the Golgi vicinity in quiescent NSCs and are required for proper localization of Golgi proteins, including the Golgi-resident small GTPase Arf1 known to regulate quiescent NSC reactivation and regeneration. Moreover, Drosophila kinetochore proteins physically associate with Arf1 and function upstream of it during reactivation. Remarkably, human kinetochore protein SPC25 localizes to Golgi in interphase NSCs and HEK293T cells. Furthermore, human kinetochores have a conserved function in promoting Golgi organization and, in turn, microtubule dynamics, in interphase cells. Together, our findings reveal a conserved moonlighting role for kinetochores in Golgi assembly in quiescent Drosophila NSCs and human interphase cells.