Biophys J, October 2002, p. 2162-2169, Vol. 83, No. 4

Functional State of the Axonemal Dyneins during Flagellar Bend Propagation

Department of Physiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom

When mouse spermatozoa swim in media of high viscosity, additional waves of bending are superimposed on the primary traveling wave. The additional (secondary) waves are relatively small in scale and high in frequency. They originate in the proximal part of the interbend regions. The initiation of secondary bending happens only in distal parts of the flagellum. The secondary waves propagate along the interbends and then tend to die out as they encounter the next-most-distal bend of the primary wave, if that bend exceeds a certain angle. The principal bends of the primary wave, being of greater angle than the reverse bends, strongly resist invasion by the secondary waves; when a principal bend of the primary wave propagates off the flagellar tip, the secondary wave behind it suddenly increases in amplitude. We claim that the functional state of the dynein motors in relation to the primary wave can be deduced from their availability for recruitment into secondary wave activity. Therefore, only the dyneins in bends are committed functionally to the maintenance and propagation of the flagellar wave; dyneins in interbend regions are not functionally committed in this way. We equate functional commitment with tension-generating activity, although we argue that the regions of dynein thus engaged nevertheless permit sliding displacements between the doublets.

Biophys J, October 2002, p. 2162-2169, Vol. 83, No. 4
© 2002 by the Biophysical Society   0006-3495/02/10/2162/08  $2.00

This article has been cited by other articles:

				G. G. Vernon and D. M. Woolley Basal Sliding and the Mechanics of Oscillation in a Mammalian Sperm Flagellum Biophys. J., December 1, 2004; 87(6): 3934 - 3944. [Abstract] [Full Text] [PDF]