DECILIATION INDUCES PHOSPHORYLATION OF A 90-KDA CORTICAL PROTEIN IN TETRAHYMENA-THERMOPHILA

We have used the anti-phosphoprotein antibody MPM-2 to examine changes in phosphorylation of cortical proteins during cilia regeneration in Tetrahymena thermophila. Although numerous cortical proteins are phosp horylated in both nondeciliated and deciliated cells, deciliation indu ces a dramatic increase in the phosphorylation of a 90-kDa cortical pr otein. The 90-kDa protein remained phosphorylated during cilia regener ation and then gradually became dephosphorylated. The 90-kDa protein w as phosphorylated and dephosphorylated normally in Tetrahymena mutants that assemble short cilia, suggesting that achievement of full length is not the signal that triggers dephosphorylation of the 90-kDa prote in. When initiation of cilia assembly is blocked, the 90-kDa protein b ecomes phosphorylated and remains phosphorylated for an extended perio d of time, suggesting that initiation of cilia elongation triggers eve ntual dephosphorylation of the 90-kDa protein, regardless of how long the cilia actually become.