IDENTIFICATION AND PARTIAL-PURIFICATION OF CALMODULIN-BINDING MICROTUBULE-ASSOCIATED PROTEINS FROM NEUROSPORA-CRASSA

We have purified microtubule-associated proteins from Neurospora crass a on the basis of heat stability and affinity to calmodulin. Two prote ins of molecular masses 170 kDa and 190 kDa have been partially purifi ed. A third protein of 145 kDa was purified almost to homogeneity, and we present evidence that this protein is a specific substrate for a C a2+/calmodulin-dependent protein kinase. The purified 170-, 190-, and 145-kDa proteins induce the assembly of microtubules from purified por cine brain tubulin. We demonstrate that all three proteins are microtu bule-associated proteins on the basis of an in vitro microtubule-bindi ng assay.