Surfing on microtubule ends.

A crowd of proteins seems to have gathered around the plus-ends of microtubules. A rapidly expanding group of proteins known as plus-end tracking proteins (+TIPs) have been identified that seem to be able to 'surf' the dynamic ends of microtubules. Microtubule plus-ends exist in multiple conformational and chemical states. In principle, altering this plus-end microenvironment is an appealing way for regulators such as the +TIPS to control microtubule dynamics; however, specific mechanisms are poorly defined. Here, we focus on new findings addressing the underlying mechanisms of plus-end tracking and the mechanisms by which +TIPS control microtubule dynamics. We review the evidence that plus-end-binding and the control of microtubule dynamics are mechanistically linked. We also consider the possibility that, by studying +TIPs, we might learn more about the dynamic structural changes at the microtubule ends that are at the heart of dynamic instability.