Interaction of brain cytoplasmic dynein and MAP2 with a common sequence at the C terminus of tubulin

Abstract

TWO main types of microtubule-associated proteins (MAPs) have been identified in neuronal cells. The fibrous MAPs, including MAP2 and tau, serve to organize and regulate the assembly of microtubules. A second distinct class of force-producing MAPs, including kinesin¹, dynein^2–4 and dynamin⁵, are involved in micro-tubule-based movement. These proteins are mechanochemical ATPases which seem to be responsible for the bidirectional transport of organelles and perhaps also the movement of chromosomes. Here we report that MAP2 inhibits microtubule gliding on dynein-coated coverslips, as well as the microtubule-activated ATPase of dynein, indicating that MAP2 and other fibrous MAPs could be important modulators of microtubule-based motility in vivo. By proteolytic modification of tubulin, we found that dynein interacts with microtubules at the C termini of α- and β-tubulin, the regions previously reported to be the sites for the interaction of MAP2^6,7. The use of site-directed antibodies implicates a small region of α- and β-tubulin, containing the sequence Glu-Gly-Glu-Glu, as the site of the interaction of dynein and MAP2 with the microtubule.