The conserved mitotic kinase polo is regulated by phosphorylation and has preferred microtubule‐associated substrates in Drosophila embryo extracts.

摘要: The Drosophila gene polo encodes a protein kinase required for progression through mitosis. Wild-type migrates as tight doublet of 67 kDa which is converted to single band by phosphatase treatment, also inactivates the kinase. We have determined putative substrates in cell-free system derived from mutant embryos. Exogenous phosphorylates proteins sizes 220 kDa, 85 and 54 greater extent when added extracts polo(1)-derived embryos compared with wild-type embryos, both cases been subject mild heat treatment inactivate endogenous kinases. Proteins same size are predominantly phosphorylated kinases present extracts, either not or poorly show that specific monoclonal antibody beta-tubulin precipitates together an associated Moreover binds enriched microtubule preparations. discuss these vitro phosphorylation results reflect effects mutations on behaviour during mitotic cycle.