Mechanics of motility: distinct dynein binding domains on alpha- and beta-tubulin.
Biochem Cell Biol 1995;
73:665-71. [PMID:
8714687 DOI:
10.1139/o95-074]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Microtubules (MTs) interact with force-generating proteins to generate a variety of intracellular movements, including intracellular particle transport, ciliary-flagellar beating, and chromosome-spindle movements during mitosis-meiosis. Relatively little is known about the mechanics of these motor-MT interactions, in part because the motor binding domains of the MT and the corresponding MT binding domains of the motor have not been well characterized. Using a flagellar motility assay, we report that the MT subunits, alpha- and beta-tubulin, each contain a dynein binding domain located near the C-termini of their respective tubulin subunits. Blocking either alpha- or beta-tubulin binding domains of dynein attenuates motility in demembranated sea urchin sperm up to 50%. Interestingly, blocking both alpha- and beta-tubulin binding domains on dynein produces much greater decreases in motility. These data suggest that flagellar dynein binds to both subunits of the MT polymer, alpha- and beta-tublin. In addition, the two subunits appear to contribute equivalent, but functionally separate, roles to flagellar motility.
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