title: Molecular motor function in axonal transport in vivo probed by genetic and computational analysis in Drosophila.
abstract: Bidirectional axonal transport driven by kinesin and dynein along microtubules is critical to neuronal viability and function. To evaluate axonal transport mechanisms, we developed a high-resolution imaging system to track the movement of amyloid precursor protein (APP) vesicles in Drosophila segmental nerve axons. Computational analyses of a large number of moving vesicles in defined genetic backgrounds with partial reduction or overexpression of motor proteins enabled us to test with high precision existing and new models of motor activity and coordination in vivo. We discovered several previously unknown features of vesicle movement, including a surprising dependence of anterograde APP vesicle movement velocity on the amount of kinesin-1. This finding is largely incompatible with the biophysical properties of kinesin-1 derived from in vitro analyses. Our data also suggest kinesin-1 and cytoplasmic dynein motors assemble in stable mixtures on APP vesicles and their direction and velocity are controlled at least in part by dynein intermediate chain.
authors.affiliation: Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Reis
authors.forename: Ge
authors.initials: G
authors.lastname: Yang
authors.forename: Lukasz
authors.initials: L
authors.lastname: Szpankowski
authors.forename: Carole
authors.initials: C
authors.lastname: Weaver
authors.forename: Sameer B
authors.initials: SB
authors.lastname: Shah
authors.forename: John T
authors.initials: JT
authors.lastname: Robinson
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hays
authors.forename: Gaudenz
authors.initials: G
authors.lastname: Danuser
authors.forename: Lawrence S B
authors.initials: LS
authors.lastname: Goldstein
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D001370:Axonal Transport / Q000502:physiology*; D001692:Biological Transport; D019295:Computational Biology; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D000072159:Dynactin Complex; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D009043:Motor Activity / Q000502:physiology; D022161:Transport Vesicles / Q000378:metabolism*
chemical_list: D016564:Amyloid beta-Protein Precursor; D029721:Drosophila Proteins; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D004398:Dyneins; D016547:Kinesins