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Purification, Characterization And Distribution Of A Calmodulin-Dependent Protein Kinase From Rat Brain Cytosol, James Richard Goldenring

Yale Medicine Thesis Digital Library

Tubulin is a major endogenous substrate for Ca('2+)- calmodulin-dependent kinase activity in rat brain cytosol. This dissertation details the purification and characterization of a calmodulin-dependent tubulin kinase from rat brain cytosol. The kinase, purified from chelated brain cytosol by sequential chromatography on phosphocellulose, calmodulin-affinity resin, and Fractogel TSK-55F, contains two calmodulin-binding, autophosphorylating subunits of 52,000 and 63,000 daltons, designated rho and sigma, respectively. The kinase holoenzyme complex has a native molecular weight of 600,000 daltons. Both kinase subunits demonstrate isoelectric points near neutrality. The kinase phosphorylated microtubule-associated protein 2, alpha tubulin and beta tubulin as major substrates. Calmodulin-dependent phosphorylation of …