Document Type

Article

Journal Title

The Journal of neuroscience : the official journal of the Society for Neuroscience

Publication Date

Spring 3-23-2011

Volume

31

Abstract

At most synapses, presynaptic Ca(2+) channels are positioned near vesicle release sites, and increasing this distance reduces synaptic strength. We examined the lateral membrane mobility of presynaptic L-type Ca(2+) channels at photoreceptor ribbon synapses of the tiger salamander (Ambystoma tigrinum) retina. Movements of individual Ca(2+) channels were tracked by coupling quantum dots to an antibody against the extracellular α(2)δ(4) Ca(2+) channel subunit. α(2)δ(4) antibodies labeled photoreceptor terminals and colocalized with antibodies to synaptic vesicle glycoprotein 2 and voltage-gated Ca(2+) channel 1.4 (Ca(V)1.4) α(1) subunits. The results show that Ca(2+) channels are dynamic and move within a confined region beneath the synaptic ribbon. The size of this confinement area is regulated by actin and membrane cholesterol. Fusion of nearby synaptic vesicles caused jumps in Ca(2+) channel position, propelling them toward the outer edge of the confinement domain. Channels rebounded rapidly toward the center. Thus, although Ca(V) channels are mobile, molecular scaffolds confine them beneath the ribbon to maintain neurotransmission even at high release rates.

MeSH Headings

Actins, Algorithms, Ambystoma, Animals, Biophysical Phenomena, Calcium Channels, L-Type, Cell Separation, Cholesterol, Female, Immunohistochemistry, Male, Movement, Photic Stimulation, Photoreceptor Cells, Vertebrate, Quantum Dots, Receptors, Presynaptic, Retina, Synapses, Tissue Fixation

ISSN

1529-2401

Creative Commons License


This work is licensed under a Creative Commons Attribution 4.0 License.

Included in

Ophthalmology Commons

Share

COinS