Mapping MAP binding

Microtubule (MT) assembly is a dynamic process involving the addition and removal of tubulin αβ heterodimers. The binding of microtubule-associated proteins (MAPs) to MTs helps to prevent depolymerization of assembled filaments. Despite years of study, there has been little consensus on the structural basis for this stabilization. Open a number of textbooks on the subject, and you are likely to find that some show MAP proteins wrapping around the microtubule, binding together the protofilaments, while others picture MAPs binding lengthwise along individual protofilaments.On page 1187, Al-Bassam et al. finally resolve the structural basis for MAP stabilization of microtubules by examining the MAP2/tau family. Stabilization of MTs by MAP2/tau proteins is required during axon and dendrite development. Although both MAP2 and the COOH terminus of tubulin with which it interacts are unstructured in solution, upon binding,...