title: Concentration of membrane antigens by forward transport and trapping in neuronal growth cones.
abstract: Formation of the nervous system requires that neuronal growth cones follow specific paths and then stop at recognition signals, sensed at the growth cone's leading edge. We used antibody-coated gold particles viewed by video-enhanced differential interference contrast microscopy to observe the distribution and movement of two cell surface molecules, N-CAM and the 2A1 antigen, on growth cones of cultured cortical neurons. Gold particles are occasionally transported forward at 1-2 microns/s to the leading edge where they are trapped but continue to move. Concentration at the edge persists after cytochalasin D treatment or ATP depletion, but active movements to and along edges cease. We also observed a novel outward movement of small cytoplasmic aggregates at 1.8 microns/s in filopodia. We suggest that active forward transport and trapping involve reversible attachment of antigens to and transport along cytoskeletal elements localized to edges of growth cones.
authors.affiliation: Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, Missouri 63110.
authors.forename: M P
authors.initials: MP
authors.lastname: Sheetz
authors.forename: N L
authors.initials: NL
authors.lastname: Baumrind
authors.forename: D B
authors.initials: DB
authors.lastname: Wayne
authors.forename: A L
authors.initials: AL
authors.lastname: Pearlman
mesh_terms: D000199:Actins / Q000032:analysis; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis*; D001386:Azides / Q000494:pharmacology; D001921:Brain / Q000166:cytology*; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis*; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D004622:Embryo, Mammalian; D051379:Mice; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D019810:Sodium Azide
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D001386:Azides; D015816:Cell Adhesion Molecules, Neuronal; D015638:Cytochalasin D; D000255:Adenosine Triphosphate; D019810:Sodium Azide; D003847:Deoxyglucose