title: Forward transport of proteins in the plasma membrane of migrating cerebellar granule cells.
abstract: Directional flow of membrane components has been detected at the leading front of fibroblasts and the growth cone of neuronal processes, but whether there exists global directional flow of plasma membrane components over the entire migrating neuron remains largely unknown. By analyzing the trajectories of antibody-coated single quantum dots (QDs) bound to two membrane proteins, overexpressed myc-tagged synaptic vesicle-associated membrane protein VAMP2 and endogenous neurotrophin receptor TrkB, we found that these two proteins exhibited net forward transport, which is superimposed upon Brownian motion, in both leading and trailing processes of migrating cerebellar granule cells in culture. Furthermore, no net directional transport of membrane proteins was observed in nonmigrating cells with either growing or stalling leading processes. Analysis of the correlation of motion direction between two QDs on the same process in migrating neurons also showed a higher frequency of correlated forward than rearward movements. Such correlated QD movements were markedly reduced in the presence of myosin II inhibitor blebbistatin,suggesting the involvement of myosin II-dependent active transport processes. Thus, a net forward transport of plasma membrane proteins exists in the leading and trailing processes of migrating neurons, in line with the translocation of the soma.
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences,  Chinese Academy of Sciences, Shanghai 200031,  China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Liang
authors.initials: L
authors.lastname: She
authors.forename: Ya-nan
authors.initials: YN
authors.lastname: Sui
authors.forename: Xiao-bing
authors.initials: XB
authors.lastname: Yuan
authors.forename: Yunqing
authors.initials: Y
authors.lastname: Wen
authors.forename: Mu-ming
authors.initials: MM
authors.lastname: Poo
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport; D001693:Biological Transport, Active; D001703:Biophysics / Q000379:methods; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement; D002531:Cerebellum / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000378:metabolism*; D004058:Diffusion; D007150:Immunohistochemistry / Q000379:methods; D009038:Motion; D024462:Myosin Type II / Q000378:metabolism; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D021381:Protein Transport; D045663:Quantum Dots; D051381:Rats
chemical_list: D024462:Myosin Type II