Novel clustering of sodium channel Na(v)1.1 with ankyrin-G and neurofascin at discrete sites in the inner plexiform layer of the retina.
Voltage-gated sodium channels cluster at sites of action potential generation and propagation by interacting with partner proteins such as neurofascin, an adhesion molecule in the L1 family, and ankyrin-G, a spectrin-binding protein required for sodium channel accumulation at axon initial segments. Here, we describe in the inner plexiform layer of the retina a novel site of high-density sodium channel clustering, marked by ankyrin-G and neurofascin. The sodium channel isoform at this site is Na(v)1.1, instead of the Na(v)1.6 channels more commonly found in association with the clustering machinery. During development, Na(v)1.2 channels first associate with ankyrin-G in the inner plexiform layer but are later replaced by Na(v)1.1, similar to the switch from Na(v)1.2 to Na(v)1.6 at nodes of Ranvier and initial segments. This represents the first instance of high-density clustering of Na(v)1.1 channels, which may contribute to synaptic interactions among retinal neurons in the inner plexiform layer.
Van Wart
Audra
A
Department of Neurobiology and Behavior, Centers for Molecular Medicine, State University of New York, Stony Brook, NY 11794-5230, USA.
Boiko
Tatiana
T
Trimmer
James S
JS
Matthews
Gary
G
D000818:Animals; D017487:Ankyrins / Q000378:metabolism*; D001665:Binding Sites / Q000502:physiology; D019556:COS Cells; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002522:Chlorocebus aethiops; D006801:Humans; D051379:Mice; D062550:NAV1.1 Voltage-Gated Sodium Channel; D009414:Nerve Growth Factors / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000737:chemistry* / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism*
C490614:Ank3 protein, rat; D017487:Ankyrins; D015815:Cell Adhesion Molecules; D062550:NAV1.1 Voltage-Gated Sodium Channel; C054305:NFASC protein, human; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; C504593:Nfasc protein, mouse; C504594:Nfasc protein, rat; C568242:SCN1A protein, human; C568249:Scn1a protein, mouse; C568250:Scn1a protein, rat; D015222:Sodium Channels