The architecture of active zone material at the frog's neuromuscular junction.
Active zone material at the nervous system's synapses is situated next to synaptic vesicles that are docked at the presynaptic plasma membrane, and calcium channels that are anchored in the membrane. Here we use electron microscope tomography to show the arrangement and associations of structural components of this compact organelle at a model synapse, the frog's neuromuscular junction. Our findings indicate that the active zone material helps to dock the vesicles and anchor the channels, and that its architecture provides both a particular spatial relationship and a structural linkage between them. The structural linkage may include proteins that mediate the calcium-triggered exocytosis of neurotransmitter by the synaptic vesicles during synaptic transmission.
Harlow
M L
ML
Department of Neurobiology, Stanford University School of Medicine, California 94305, USA.
Ress
D
D
Stoschek
A
A
Marshall
R M
RM
McMahan
U J
UJ
D000818:Animals; D015220:Calcium Channels / Q000502:physiology; D007089:Image Enhancement; D008565:Membrane Proteins / Q000502:physiology / Q000648:ultrastructure; D009419:Nerve Tissue Proteins / Q000502:physiology / Q000648:ultrastructure; D009469:Neuromuscular Junction / Q000502:physiology / Q000648:ultrastructure*; D015388:Organelles / Q000502:physiology / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000502:physiology / Q000648:ultrastructure; D011894:Rana pipiens; D013570:Synaptic Membranes / Q000502:physiology / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000502:physiology / Q000648:ultrastructure
D015220:Calcium Channels; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins