eLife (Sep 2020)

A dual role for Cav1.4 Ca2+ channels in the molecular and structural organization of the rod photoreceptor synapse

  • J Wesley Maddox,
  • Kate L Randall,
  • Ravi P Yadav,
  • Brittany Williams,
  • Jussara Hagen,
  • Paul J Derr,
  • Vasily Kerov,
  • Luca Della Santina,
  • Sheila A Baker,
  • Nikolai Artemyev,
  • Mrinalini Hoon,
  • Amy Lee

DOI
https://doi.org/10.7554/eLife.62184
Journal volume & issue
Vol. 9

Abstract

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Synapses are fundamental information processing units that rely on voltage-gated Ca2+ (Cav) channels to trigger Ca2+-dependent neurotransmitter release. Cav channels also play Ca2+-independent roles in other biological contexts, but whether they do so in axon terminals is unknown. Here, we addressed this unknown with respect to the requirement for Cav1.4 L-type channels for the formation of rod photoreceptor synapses in the retina. Using a mouse strain expressing a non-conducting mutant form of Cav1.4, we report that the Cav1.4 protein, but not its Ca2+ conductance, is required for the molecular assembly of rod synapses; however, Cav1.4 Ca2+ signals are needed for the appropriate recruitment of postsynaptic partners. Our results support a model in which presynaptic Cav channels serve both as organizers of synaptic building blocks and as sources of Ca2+ ions in building the first synapse of the visual pathway and perhaps more broadly in the nervous system.

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