Microtubule-associated proteins: their potential role in determining neuronal morphology

The microtubule-associated proteins (MAPs) are a heterogeneous group of molecules that co-purify with tubulin when microtubules are repolymerized from brain homogenates. A variety of data implicate them in regulating the stability of microtubules in axons and dendrites and hence suggest that they are involved in determining neuronal shape and, more importantly, in regulating the balance between rigidity and plasticity in neuronal processes. In this review the author considers some properties of the MAPs that bear on this question and attempt to assess critically their interpretation.