Concentration of membrane antigens by forward transport and trapping in neuronal growth cones.
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.
Sheetz
M P
MP
Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, Missouri 63110.
Baumrind
N L
NL
Wayne
D B
DB
Pearlman
A L
AL
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
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