Distribution of acetylated alpha-tubulin in brain. In situ localization and biochemical characterization

We studied the solubility properties of brain acetylated alpha-tubulin, as well as the localization of this tubulin in brain tissue. Endogenous unpolymerized tubulin and cytoskeletal tubulin were fractionated after brain Triton-solubilization. Using the immunoblotting technique, we found that acetylated alpha-tubulin was recovered in the cytoskeletal fraction, and that most (92%) of the acetylated microtubules of this fraction were depolymerized by cold/Ca2+ treatment. In another set of experiments, axonal and soma-dendritic preparations were found to have equivalent amounts of acetylated alpha-tubulin. By immunogold electron microscopy, we established that acetylated microtubules are widely distributed in dendrites of the central nervous system.