Inhibition of microtubule assembly by phosphorylation of microtubule-associated proteins.

摘要: 32P labeling of microtubular protein by endogenous kinase activity is shown to result from a net increase in protein-bound phosphate and not the exchange reaction between ATP phosphoprotein. Protein phosphorylation maximal presence 0.5 mM Mg2+ 0.25 ATP, resulting approximately 2.8 nmol phosphate/mg protein. However, can be increased two-to threefold cAMP. The substrates for either absence or cAMP are microtubule-associated proteins which copurify with tubulin promote microtubule assembly. Phosphorylation inhibits both rate extent assembly when exposed conditions dissociation rings. These results taken indicate that modifies MAPs so they have reduced ability form an assembly-competent complex tubulin.