MAP2: a sensitive cross-linker and adjustable spacer in dendritic architecture.

Microtubule-associated protein 2 (MAP2), a long, filamentous molecule thought to cross-link dendritic cytoskeleton, is rich in PEST sequences, putative signals for rapid proteolytic degradation. It is suggested that MAP2 is indeed highly susceptible to protease, e.g. calpain, attack, which is needed for a plastic change, but actual breakdown depends on the regulation of protease(s). Phosphorylation is expected to make the molecule longer and rigid, similarly to what was observed with the related tau protein. Such a structural transition may provide a mechanism for the putative role of MAP2 in dendritic branching.