DNCIC1: Proteins and Enzymes

Eukaryotic cells rely on actin and microtubule-based protein "motors" to generate intracellular movements.4 These protein "motors" contain specialized domains that hydrolyse ATP to produce force and movement along a cytoskeletal polymer (actin in the case of myosin family and microtubules in the case of the kinesin family and dyneins). The minus-end-directed, microtubule motor, dynein ATPase is one of the most widely studied microtubule-associated energy transducing enzymes. It constitutes the outer and inner arms on the doublet tubules of sperm flagellar axonemes, where it generates the sliding between doublets that underlies flagellar beating. Dynein has also been implicated in cytoplasmic motile functions, including chromosomal movement, retrograde organelle and axonal transport, the endocytic pathway, and the organization of the Golgi apparatus. In all cell types, dynein has the same basic structures and is composed of two or three distinct heavy chains (approximately 450 kDa), three intermediate chains (70-125 kDa), and at least four light chains (15-25 kDa).5