An unusual cGMP pathway underlying depolarizing light response of the vertebrate parietal-eye photoreceptor

Wei Hong Xiong, Eduardo C. Solessio, King-Wai Yau

Research output: Contribution to journalArticlepeer-review

Abstract

All cellular signaling pathways currently known to elevate cGMP involve the activation of a guanylyl cyclase to synthesize cGMP. Here we describe an exception to this rule. In the vertebrate parietal eye, the photoreceptors depolarize to light under dark-adapted conditions, unlike rods and cones but like most invertebrate photoreceptors. We report that the signaling pathway for this response involves a rise in intracellular cGMP resulting from an inhibition of the phosphodiesterase that hydrolyzes cGMP. Furthermore, this phosphodiesterase is driven by an active G protein in darkness. These results indicate an antagonistic control of the phosphodiesterase by two G proteins, analogous to the GS/Gi control of adenylyl cyclase. Our findings demonstrate an unusual phototrans-duction mechanism and at the same time indicate that signaling involving cyclic nucleotides is more elaborate than previously known.

Original languageEnglish (US)
Pages (from-to)359-365
Number of pages7
JournalMolecular Cell
Volume1
Issue number5
StatePublished - 1998

ASJC Scopus subject areas

  • Molecular Biology

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