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 language | English (US) |
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Pages (from-to) | 359-365 |
Number of pages | 7 |
Journal | Molecular Cell |
Volume | 1 |
Issue number | 5 |
State | Published - 1998 |
ASJC Scopus subject areas
- Molecular Biology