Dominant-negative myosin Va impairs retrograde but not anterograde axonal transport of large dense core vesicles.
Axonal transport of peptide and hormone-containing large dense core vesicles (LDCVs) is known to be a microtubule-dependent process. Here, we suggest a role for the actin-based motor protein myosin Va specifically in retrograde axonal transport of LDCVs. Using live-cell imaging of transfected hippocampal neurons grown in culture, we measured the speed, transport direction, and the number of LDCVs that were labeled with ectopically expressed neuropeptide Y fused to EGFP. Upon expression of a dominant-negative tail construct of myosin Va, a general reduction of movement in both dendrites and axons was observed. In axons, it was particularly interesting that the retrograde speed of LDCVs was significantly impaired, although anterograde transport remained unchanged. Moreover, particles labeled with the dominant-negative construct often moved in the retrograde direction but rarely in the anterograde direction. We suggest a model where myosin Va acts as an actin-dependent vesicle motor that facilitates retrograde axonal transport.
Department of Biomedicine, University of Bergen, Jonas-Lies vei 91, 5009, Bergen, Norway.
Claudia Margarethe
CM
Bittins
Tilo Wolf
TW
Eichler
John A
JA
Hammer
Hans-Hermann
HH
Gerdes
D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D001370:Axonal Transport / Q000502:physiology*; D001369:Axons / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism* / Q000648:ultrastructure; D019044:Image Cytometry; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000378:metabolism*; D024701:Myosin Type V / Q000378:metabolism*; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D013194:Staining and Labeling; D014162:Transfection
D020409:Molecular Motor Proteins; C513081:Myo5a protein, rat; D009478:Neuropeptide Y; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D024701:Myosin Type V; D018995:Myosin Heavy Chains