The interactions between calcium-dependent regulator protein of cyclic nucleotide phosphodiesterase and microtubule proteins. II. Association of calcium-dependent regulator protein with tubulin dimer.
The Ca2+-dependent regulator protein (CDR) of cyclic nucleotide phosphodiesterase (PDE) was reported to be a Ca2+-dependent regulator of microtubule (MT) assembly in the preceding paper. In this paper, the binding of Ca2+-CDR complex to tubulin dimer was investigated in order to elucidate the Ca2+-dependent inhibitory action of CDR on MT assembly. Purified microtubular proteins (PMPs) isolated from porcine brain did not affect the ability of CDR to activate Ca2+-activatable PDE, and did not include any inhibitory protein of Ca2+-activatable PDE. The binding of CDR to the tubulin dimer was observed on Sephadex G-200 gel filtration and ammonium sulfate fractionation in a Ca2+-dependent manner. CDR did not bind to microtubule associated proteins. We now assume that Ca2+-dependent inhibition of MT assembly by CDR is due to the binding of CDR to tubulin dimer in a Ca2+-dependent manner.
D000818:Animals; D001921:Brain / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008870:Microtubules / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011485:Protein Binding; D013552:Swine; D014404:Tubulin / Q000378:metabolism*
D002147:Calmodulin; D002352:Carrier Proteins; D006023:Glycoproteins; D046911:Macromolecular Substances; D014404:Tubulin; D010727:Phosphoric Diester Hydrolases