Eukaryotic cilia and flagella are found widely in plants, animals and protozoa. The structure and basic mechanism of function of eukaryotic cilia and flagella is common among these wide variety of organisms. This proposal is aimed toward understanding the mechanism and regulation of eukaryotic flagellar movement. The specific aim is to determine how the dynein mechanochemical cycle regulates movement. The approach taken is to develop the use of compounds with specific effect on dynein kinetics to study their effect on movement. One compound already identified for this study is the two-substituted ATP analog, 2- C1 ATP. In contrast to previously studied ATP analogs, 2-C1 ATP is a surprisingly good substrate for dynein ATPase activity and supports axonemal movement. This and other analogs will be used to determine how effects on dynein affect axonemal movement by studying their effect on steps in the dynein-microtubule ATPase cycle and dynein-mediated microtuble sliding. This approach will allow elucidation of which step in the dynein mechanochemical cycle may be associated with paramenters of movement. Ciliary and flagellar motility is a fundamental kind of motility which is critical to the lives of all kinds of eukaryotic organisms. The simple protists, and spermatozoa, are propelled by this mechanism. In higher animals, cilia are used move mucus to better understand the molecular aspects of this remarkable biological function.
