Microtubule binding of the Drosophila DMAP-85 protein is regulated by phosphorylation in vitro

The phosphorylation of microtubule-associated proteins (MAPs) is thought to be a key factor in the regulation of microtubule (MT) stability. Previousl y we isolated DMAP-85, a Drosophila MAP shown to be associated with stable MTs. In this work we show that DMAP-85 phosphorylated in cell-free early em bryo extracts is released from MTs, MPM-2 antibodies recognize the phosphor ylated protein. In vitro, DMAP-85 can be phosphorylated by the mitotic kina se Polo affecting its binding to MTs and creating MPM-2 epitopes on the pro tein. The results suggest that phosphorylation of DMAP-85 might affect its MT stabilizing activity during early mitotic cycles. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rig hts reserved.