Protein phosphorylation and the regulation of basal body microtubule organizing centres in Tetrahymena.

Previous work suggests that changes in the phosphorylation state of some centrosomal proteins regulate centrosomal activity. The hypothesis that changes in the phosphorylation state of one or more basal body microtubule organizing centre (MTOC) components regulate its ability to nucleate cilia assembly in Tetrahymena thermophila was tested. The MPM-2 antibody, which recognizes phosphorylated epitopes in MTOCs in a variety of organisms, was used to probe immunoblots of cytoskeletal frameworks prepared from starved Tetrahymena, from starved deciliated Tetrahymena, and from a starved deciliated mutant Tetrahymena which failed to initiate ciliogenesis following deciliation. The MPM-2 antibody recognized an identical array of proteins in all blots. These results suggest that, unlike centrosomes, basal body MTOC activity is not regulated by changes in the phosphorylation state of component proteins.