Components of the Hippo pathway cooperate with Nek2 kinase to regulate centrosome disjunction

During interphase, centrosomes are held together by a proteinaceous linker that connects the proximal ends of the mother and daughter centriole. This linker is disassembled at the onset of mitosis in a process known as centrosome disjunction, thereby facilitating centrosome separation and bipolar spindle formation. The NIMA (never in mitosis A)-related kinase Nek2A is implicated in disconnecting the centrosomes through disjoining the linker proteins C-Nap1 and rootletin. However, the mechanisms controlling centrosome disjunction remain poorly understood. Here, we report that two Hippo pathway components, the mammalian sterile 20-like kinase 2 (Mst2) and the scaffold protein Salvador (hSav1), directly interact with Nek2A and regulate its ability to localize to centrosomes, and phosphorylate C-Nap1 and rootletin. Furthermore, we demonstrate that the hSav1-Mst2-Nek2A centrosome disjunction pathway becomes essential for bipolar spindle formation on partial inhibition of the kinesin-5 Eg5. We propose that hSav1-Mst2-Nek2A and Eg5 have distinct, but complementary functions, in centrosome disjunction.