Calmodulin Confers Calcium Sensitivity on Ciliary Dynein ATPase

• Published in: The Journal of cell biology 1980-11, Vol.87 (2), p.386-397
• Main Authors: Blum, J. J., Hayes, Alvernon, Jamieson, Gordon A., Vanaman, Thomas C.
• Format: Article
• Language: English
• Subjects: Adenine Nucleotides - pharmacology; Adenosine triphosphatases; Adenosine Triphosphatases - metabolism; Animals; Binding sites; Calcium; Calcium - physiology; Calcium-Binding Proteins - physiology; Calmodulin - antagonists & inhibitors; Calmodulin - physiology; Cell Fractionation - methods; Chlorpromazine - pharmacology; Chromatography; Chromatography, Affinity; Cilia; Cilia - enzymology; Dyneins - antagonists & inhibitors; Dyneins - isolation & purification; Dyneins - metabolism; Flagella; Gels; Molecular Weight; Skeletal muscle; Tetrahymena pyriformis - enzymology; Tetrahymena pyriformis - ultrastructure; Troponin - pharmacology; Ungulates
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.87.2.386

Extraction of demembranated cilia of Tetrahymena by Tris-EDTA (denoted by the suffix E) yields 14S-E and 30S-E dyneins with ATPase activities that are slightly increased by Ca++. This effect is moderately potentiated when bovine brain calmodulin is added to the assay mixture. Extraction with 0.5 M KCI (denoted by the suffix K) yields a 14S-K dynein with a low basal ATPase activity in the presence of Ca++. Subsequent addition of calmodulin causes marked activation (up to 10-fold) of ATPase activity. Although 14S-K and 14S-E dyneins have Ca++-dependent ATPase activities that differ markedly in the degree of activation, the concentration of calmodulin required for half-maximal saturation is similar for both, ∼0.1 μM. Both 30S-K and 30S-E dyneins, however, require ∼0.7 μM bovine brain calmodulin to reach half-maximal activation of their Ca++-dependent ATPase activities. Tetrahymena calmodulin is as effective as bovine brain calmodulin in activating 30S dynein, but may be slightly less effective than the brain calmodulin in activating 14S dynein. Rabbit skeletal muscle troponin C also activates the Ca++-dependent ATPase activity of 30S dynein and, to a lesser extent, that of 14S dynein, but in both cases is less effective than calmodulin. The interaction of calmodulin with dynein that results in ATPase activation is largely complete in