High molecular weight microtubule-associated proteins are preferentially associated with dendritic microtubules in brain.

TLDR

Immunoperoxidase histochemistry with specific antisera mapped tubulin and high‑molecular‑weight microtubule‑associated proteins in brain tissue. Tubulin is present in microtubules of neurons, glia, axons, and dendrites, whereas high‑molecular‑weight microtubule‑associated proteins are restricted to neuronal dendritic microtubules and postsynaptic densities, indicating chemical heterogeneity of brain microtubules and suggesting HMWPs help differentiate dendritic from axonal transport routes.

Abstract

The distributions of tubulin and high molecular weight microtubule-associated proteins (HMWPs) in brain were determined by immunoperoxidase histochemistry with specific antisera. Tubulin was found in microtubules of both neurons and glia and both axons and dendrites. HMWPs were found only in neurons where, in all cases examined, they were associated with dendritic microtubules but not those in axons. Both tubulin and HMWPs were also found in postsynaptic densities. These results indicate that brain microtubules vary in chemical composition. The preferential association of HMWPs with dendritic microtubules suggests that they may play a role in distinguishing between dendritic and axonal export routes from the cell body.