title: Motor proteins regulate force interactions between microtubules and microfilaments in the axon.
abstract: It has long been known that microtubule depletion causes axons to retract in a microfilament-dependent manner, although it was not known whether these effects are the result of motor-generated forces on these cytoskeletal elements. Here we show that inhibition of the motor activity of cytoplasmic dynein causes the axon to retract in the presence of microtubules. This response is obliterated if microfilaments are depleted or if myosin motors are inhibited. We conclude that axonal retraction results from myosin-mediated forces on the microfilament array, and that these forces are counterbalanced or attenuated by dynein-mediated forces between the microfilament and microtubule arrays.
authors.affiliation: Department of Anatomy, University of Wisconsin Medical School, Madison 53706, USA.
authors.forename: F J
authors.initials: FJ
authors.lastname: Ahmad
authors.forename: J
authors.initials: J
authors.lastname: Hughey
authors.forename: T
authors.initials: T
authors.lastname: Wittmann
authors.forename: A
authors.initials: A
authors.lastname: Hyman
authors.forename: M
authors.initials: M
authors.lastname: Greaser
authors.forename: P W
authors.initials: PW
authors.lastname: Baas
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001369:Axons / Q000502:physiology*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D003593:Cytoplasm / Q000378:metabolism; D004398:Dyneins / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000166:cytology; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects / Q000502:physiology*; D020409:Molecular Motor Proteins / Q000502:physiology*; D009218:Myosins / Q000037:antagonists & inhibitors / Q000378:metabolism; D009475:Neurons, Afferent / Q000166:cytology; D015739:Nocodazole / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000970:Antineoplastic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D013844:Thiazoles; D053778:Thiazolidines; D009218:Myosins; D004398:Dyneins; D005033:Ethylmaleimide; D015739:Nocodazole; C037067:latrunculin A