title: Role of kinesin-1-based microtubule sliding in Drosophila nervous system development.
abstract: The plus-end microtubule (MT) motor kinesin-1 is essential for normal development, with key roles in the nervous system. Kinesin-1 drives axonal transport of membrane cargoes to fulfill the metabolic needs of neurons and maintain synapses. We have previously demonstrated that kinesin-1, in addition to its well-established role in organelle transport, can drive MT-MT sliding by transporting "cargo" MTs along "track" MTs, resulting in dramatic cell shape changes. The mechanism and physiological relevance of this MT sliding are unclear. In addition to its motor domain, kinesin-1 contains a second MT-binding site, located at the C terminus of the heavy chain. Here, we mutated this C-terminal MT-binding site such that the ability of kinesin-1 to slide MTs is significantly compromised, whereas cargo transport is unaffected. We introduced this mutation into the genomic locus of kinesin-1 heavy chain (KHC), generating the Khc(mutA) allele. Khc(mutA) neurons displayed significant MT sliding defects while maintaining normal transport of many cargoes. Using this mutant, we demonstrated that MT sliding is required for axon and dendrite outgrowth in vivo. Consistent with these results, Khc(mutA) flies displayed severe locomotion and viability defects. To test the role of MT sliding further, we engineered a chimeric motor that actively slides MTs but cannot transport organelles. Activation of MT sliding in Khc(mutA) neurons using this chimeric motor rescued axon outgrowth in cultured neurons and in vivo, firmly establishing the role of sliding in axon outgrowth. These results demonstrate that MT sliding by kinesin-1 is an essential biological phenomenon required for neuronal morphogenesis and normal nervous system development.
authors: Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611;
authors: Michael
authors: M
authors: Winding
authors: Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706; Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, WI 53706.
authors: Michael T
authors: MT
authors: Kelliher
authors: Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611;
authors: Wen
authors: W
authors: Lu
authors: Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706;
authors: Jill
authors: J
authors: Wildonger
authors: Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611; vgelfand@northwestern.edu.
authors: Vladimir I
authors: 0000-0002-6361-2798
authors: VI
authors: Gelfand
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001370:Axonal Transport / Q000235:genetics; D001665:Binding Sites; D001696:Biomechanical Phenomena; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D016547:Kinesins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009154:Mutation; D009420:Nervous System / Q000254:growth & development / Q000378:metabolism*; D055495:Neurogenesis / Q000235:genetics*; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D011485:Protein Binding; D000072417:Protein Domains; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D029721:Drosophila Proteins; C515209:Khc protein, Drosophila; D016547:Kinesins
keywords: Drosophila; axon outgrowth; dendrite outgrowth; kinesin-1; microtubules