Role of Nonmotor Microtubule‐Associated Proteins in Mitotic Spindle Assembly

Abstract

The assembly of a microtubule (MT)‐based bipolar spindle is a distinct hallmark of mitosis. Mitotic spindle assembly is tightly controlled in order to ensure proper chromosome attachment and segregation during mitosis. This regulation is achieved by the coordinated action of many motor and nonmotor MT‐associated proteins (MAPs). Owing to the distinctive capacity of MAPs to associate with the MT minus and/or plus ends, as well as with the MT lattice, they play an essential role in the spatial and temporal regulation of MT behaviour during mitotic spindle assembly. Key Concepts The mitotic spindle is a dynamic structure composed of microtubules, motor and nonmotor proteins. Proper chromosome alignment and segregation during mitosis requires bipolar spindle assembly. Nonmotor microtubule‐associated proteins are involved in spindle pole focusing, microtubule dynamics, kinetochore‐microtubule attachment stability and cytokinesis. Nonmotor microtubule‐associated proteins associate with microtubule plus and minus ends (+TIPs and −TIPs, respectively) as well as with the microtubule lattice. Nonmotor microtubule‐associated proteins are tightly regulated during the cell cycle.