Figure 6.

p150^Glued enhances microtubule polymerization, but EB1 appears to have little effect. Microtubules were polymerized in the presence of tubulin alone, tubulin with recombinant p150^Glued, tubulin with recombinant EB1, or tubulin with both EB1 and p150^Glued and then centrifuged at 39,000 × g. Supernatant and pellet fractions were analyzed by SDS-PAGE. The addition of p150^Glued increased the amount of tubulin in the pellet, but EB1 had little effect. The addition of EB1 and p150^Glued together had no apparent effect beyond that of p150^Glued alone. We note that the combination of EB1 and p150^Glued in the absence of tubulin results in the appearance of both proteins in the pellet. This could result from the formation of aggregates of EB1 and p150^Glued or a change in the solubility of the proteins in solution.