Spindly switch controls anaphase: spindly and RZZ functions in chromosome attachment and mitotic checkpoint control.

Spindly is a coiled-coil domain containing protein, also known as CCDC99, that is an important regulator of the mitotic checkpoint. It belongs to a functionally conserved family of proteins that controls the localization and function of cytoplasmic dynein at kinetochores. At kinetochores Spindly interacts with the RZZ (Rod/ZW10/Zwilch) complex and is required for the recruitment of cytoplasmic dynein to kinetochores. Loss of Spindly results in loss of kinetochore dynein functions, which impairs poleward chromosome movements and mitotic checkpoint inactivation. In addition, Spindly regulates the establishment of stable microtubule attachments via regulation of the RZZ complex. Thus, Spindly couples dynein-mediated poleward chromosome movements to the establishment of stable microtubule attachments and subsequent mitotic checkpoint inactivation and provides an important switch for the control of mitosis.