I. Irminger-finger et Ro. Perez, Analysis of structure and microtubule assembly activity of the Drosophila 205K MAP, BIOL CHEM, 379(11), 1998, pp. 1381-1386
Phosphorylation, dimerization and binding to calmodulin have been reported
to influence the microtubule assembly capacities of MAPs (microtubule-assoc
iated proteins). Here we report that the Drosophila 205K MAP is a phosphopr
otein in vivo and can be phosphorylated by cdc2/p34 in vitro. Bacterially p
roduced 205K MAP is competent of microtubule assembly and microtubule bundl
ing and binds to immobilized calmodulin in a Ca2+-dependent way. EM rotary
shadowing analyses suggest that 205K MAP consists of an amino-terminal flex
ible extended region and a carboxy-terminal globular domain. This carboxy-t
erminal region harbors the microtubule binding site and sequences required
for dimerization, as confirmed by in vitro crosslinking experiments of trun
cated proteins.