A change in the selective translocation of the Kinesin-1 motor domain marks the initial specification of the axon.
We used the accumulation of constitutively active kinesin motor domains as a measure of where kinesins translocate in developing neurons. Throughout development, truncated Kinesin-3 accumulates at the tips of all neurites. In contrast, Kinesin-1 selectively accumulates in only a subset of neurites. Before neurons become polarized, truncated Kinesin-1 accumulates transiently in a single neurite. Coincident with axon specification, truncated Kinesin-1 accumulates only in the emerging axon and no longer appears in any other neurite. The translocation of Kinesin-1 along a biochemically distinct track leading to the nascent axon could ensure the selective delivery of Kinesin-1 cargoes to the axon and hence contribute to its molecular specification. Imaging YFP-tagged truncated Kinesin-1 provides the most precise definition to date of when neuronal polarity first emerges and allows visualization of the molecular differentiation of the axon in real time.
Jacobson
Catherine
C
Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon 97239, USA.
Schnapp
Bruce
B
Banker
Gary A
GA
D000818:Animals; D001370:Axonal Transport / Q000502:physiology*; D001369:Axons / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D006624:Hippocampus / Q000166:cytology; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins; D020409:Molecular Motor Proteins / Q000502:physiology*; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000166:cytology; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D013997:Time Factors; D014162:Transfection / Q000379:methods
D015415:Biomarkers; D008164:Luminescent Proteins; D020409:Molecular Motor Proteins; D016547:Kinesins