title: Molecular microdomains in a sensory terminal, the vestibular calyx ending.
abstract: Many primary vestibular afferents form large cup-shaped postsynaptic terminals (calyces) that envelope the basolateral surfaces of type I hair cells. The calyceal terminals both respond to glutamate released from ribbon synapses in the type I cells and initiate spikes that propagate to the afferent's central terminals in the brainstem. The combination of synaptic and spike initiation functions in these unique sensory endings distinguishes them from the axonal nodes of central neurons and peripheral nerves, such as the sciatic nerve, which have provided most of our information about nodal specializations. We show that rat vestibular calyces express an unusual mix of voltage-gated Na and K channels and scaffolding, cell adhesion, and extracellular matrix proteins, which may hold the ion channels in place. Protein expression patterns form several microdomains within the calyx membrane: a synaptic domain facing the hair cell, the heminode abutting the first myelinated internode, and one or two intermediate domains. Differences in the expression and localization of proteins between afferent types and zones may contribute to known variations in afferent physiology.
authors: Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA. alysakow@uic.edu
authors: Anna
authors: A
authors: Lysakowski
authors: Sophie
authors: S
authors: Gaboyard-Niay
authors: Irina
authors: I
authors: Calin-Jageman
authors: Shilpa
authors: S
authors: Chatlani
authors: Steven D
authors: SD
authors: Price
authors: Ruth Anne
authors: RA
authors: Eatock
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D017487:Ankyrins / Q000378:metabolism; D064032:Calbindin 2; D002352:Carrier Proteins / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism; D051638:Ether-A-Go-Go Potassium Channels / Q000378:metabolism; D005260:Female; D018069:Hair Cells, Vestibular / Q000145:classification / Q000378:metabolism*; D021621:Imaging, Three-Dimensional; D008297:Male; D021962:Membrane Microdomains / Q000378:metabolism* / Q000648:ultrastructure; D008840:Microfilament Proteins / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods; D016253:Microscopy, Immunoelectron / Q000379:methods; D004676:Myelin Basic Protein / Q000378:metabolism; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009414:Nerve Growth Factors / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D019063:Tenascin / Q000378:metabolism; D014725:Vestibular Nerve / Q000166:cytology*; D013049:Spectrin
chemical_list: D017487:Ankyrins; D064032:Calbindin 2; D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal; D051638:Ether-A-Go-Go Potassium Channels; D008840:Microfilament Proteins; D004676:Myelin Basic Protein; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D024642:Potassium Channels, Voltage-Gated; D064030:S100 Calcium Binding Protein G; D015222:Sodium Channels; D019063:Tenascin; D013049:Spectrin; C432674:Ank2 protein, rat; C105177:Cntnap1 protein, rat; C109500:Kcnh6 protein, rat; C436006:Mbp protein, rat; C504594:Nfasc protein, rat; C568250:Scn1a protein, rat