Illumination of the melanopsin signaling pathway

Satchidananda Panda, Surendra K. Nayak, Brice Campo, John R. Walker, John B. Hogenesch, Tim Jegla

Research output: Contribution to journalArticle

350 Scopus citations

Abstract

In mammals, a small population of intrinsically photosensitive retinal ganglion cells (ipRGCs) plays a key role in the regulation of nonvisual photic responses, such as behavioral responses to light, pineal melatonin synthesis, pupillary light reflex, and sleep latency. These ipRGCs also express melanopsin (Opn4), a putative opsin-family photopigment that has been shown to play a role in mediating these nonvisual photic responses. Melanopsin is required for the function of this inner retinal pathway, but its precise role in generating photic responses has not yet been determined. We found that expression of melanopsin in Xenopus oocytes results in light-dependent activation of membrane currents through the Gαq/Gα11 G protein pathway, with an action spectrum closely matching that of melanopsin-expressing ipRGCs and of behavioral responses to light in mice lacking rods and cones. When coexpressed with arrestins, melanopsin could use all-trans-retinaldehyde as a chromophore, which suggests that it may function as a bireactive opsin. We also found that melanopsin could activate the cation channel TRPC3, a mammalian homolog of the Drosophila phototransduction channels TRP and TRPL. Melanopsin therefore signals more like an invertebrate opsin than like a classical vertebrate rod-and-cone opsin.

Original languageEnglish (US)
Pages (from-to)600-604
Number of pages5
JournalScience
Volume307
Issue number5709
DOIs
StatePublished - Jan 28 2005

All Science Journal Classification (ASJC) codes

  • General

Fingerprint Dive into the research topics of 'Illumination of the melanopsin signaling pathway'. Together they form a unique fingerprint.

  • Cite this

    Panda, S., Nayak, S. K., Campo, B., Walker, J. R., Hogenesch, J. B., & Jegla, T. (2005). Illumination of the melanopsin signaling pathway. Science, 307(5709), 600-604. https://doi.org/10.1126/science.1105121