Throughout the course you have heard about the Ras GTPase family. Tubulin is also a GTPase that is distantly related to this family. Tubulin dimers hydrolyze GTP at a very slow intrinsic rate. When incorporated into a microtubule, however, their rate of GTP hydrolysis increases dramatically. As you will remember, GTPase activating proteins (GAPs) increase the rate at which Ras hydrolyzes GTP. What is the GAP for tubulin?

a)Dynein
b)Map2
c)Tubulin
d)Tau
e)Kinesin