Microtubule tip-interacting proteins: a view from both ends.

Microtubule ends serve as sites of tubulin addition and removal, and at the same time play crucial roles in microtubule capture, stabilization and attachment to different cellular structures. Microtubule plus and minus-ends possess distinct structural and dynamic properties, and are recognized, bound and regulated by diverse factors. These include specific capping factors such as γ-tubulin, motors, such as plus-end and minus-end directed kinesins, highly specialized kinetochore-bound microtubule-associated proteins, and comet-making plus-end tracking proteins such as EB1 and its partners. Here, we provide an overview of microtubule tip-interacting proteins and the mechanisms responsible for their association with microtubule ends, and discuss the functional cross-talk between microtubule plus and minus-end binding factors.