Polarity of dynein-microtubule interactions in vitro: cross-bridging between parallel and antiparallel microtubules.
Ciliary doublet microtubules produced by sliding disintegration in 20 muM MgATP2-reassociate in the presence of exogenous 30S dynein and 6 mM MgSO4. The doublets form overlapping arrays, held together by dynein cross-bridges. Dynein arms on both A and B subfibers serve as unambiguous markers of microtubule polarity within the arrays. Doublets reassociate via dynein cross-bridges in both parallel and antiparallel modes, although parallel interactions are favored 2:1. When 20 muM ATP is added to the arrays, the doublets undergo both vanadate-sensitive and insensitive forms of secondary disintegration to reproduce the original population of doublets. The results demonstrate that both parallel and antiparallel doublet cross-bridging is sensitive to dissociation by ATP even though normal ciliary motion depends strictly on dynein interactions between parallel microtubules.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002923:Cilia / Q000201:enzymology* / Q000648:ultrastructure; D004398:Dyneins / Q000378:metabolism*; D007700:Kinetics; D008854:Microscopy, Electron; D008870:Microtubules / Q000201:enzymology* / Q000648:ultrastructure; D013768:Tetrahymena / Q000201:enzymology*
D000251:Adenosine Triphosphatases; D004398:Dyneins