Worm Breeder's Gazette 9(3): 118
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We have identified a protein in C. bines properties of the flagellar ATPase, dynein with those of the microtubule-dependent translocator, kinesin. The microtubule stabilizing drug, taxol, has been used to drive microtubule assembly in extracts of either gravid adult worms or of embryos, and the resulting polymers have been isolated by differential centrifugation. One of the microtubule-associated proteins (Mr. approx. 400K) can be extracted from the polymer by 10 mM ATP and 100 mM NaCl. This polypeptide and a Mg-ATPase activity cosediment on sucrose density gradients at approximately 20 S. The specific activity of the peak fraction is 60 - 120 nanomoles ATP hydrolyzed/milligram protein/min. ( conditions have not yet been optimized). The activity is more than 50Z inhibited by either 10 uM vanadate, 1 mM N-ethyl maleimide or by 5 mM AMP-PNP. The ATPase is enhanced 50Z by 0.2Z Triton X-100. These properties are dynein-like. When the 20 S protein is mixed with either microtubules or flagellar axonemes on slide, it promotes a nucleotide triphosphate-dependent microtubule translocation. Axonemes glide with their 'plus' ends trailing. These properties are kinesin-like. However, microtubules move at about 0.8 - 1.0 um/sec., about twice as fast as with kinesin under conditions of saturating ATP. Furthermore, the motion is ATP-specific and is blocked by either 10 uM vanadate, 1mM N-ethyl maleimide, or by 0.5 mM ATP-gamma-S. Motility is slowed but not blocked by [AMP-PNP] = [ATP]. These characteristics and the presence of an ATPase activity differ from the properties described for kinesin. The roughly parallel inhibition of the ATPase and the motility by several reagents suggests that the enzyme activity and the motility are caused by the same protein or protein complex. We therefore propose that the 400 K protein from C. rotubule translocator which possesses properties of both dynein and kinesin.