Abstract
Rhodopsin is converted by light to an active photoproduct that triggers the transduction cascade. The active photoproduct must then be inactivated by some kind of chemical modification. The question addressed here is whether photoconversion of the inactive photoproduct to rhodopsin creates a modified form of rhodopsin that is unable to support transduction. This question was investigated in ultraviolet receptors of Limulus median eye by measuring the relative quantum efficiency of excitation after photoregeneration of rhodopsin from the inactive photoproduct. The results show that when this newly created rhodopsin absorbs a photon, no receptor potential is generated; i.e., the pigment is nontransducing. A dark process requiring 30-60 min returns rhodopsin to its transducing form.
Full Text
The Full Text of this article is available as a PDF (692.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ADOLPH A. R. SPONTANEOUS SLOW POTENTIAL FLUCTUATIONS IN THE LIMULUS PHOTORECEPTOR. J Gen Physiol. 1964 Nov;48:297–322. doi: 10.1085/jgp.48.2.297. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bennett N., Michel-Villaz M., Kühn H. Light-induced interaction between rhodopsin and the GTP-binding protein. Metarhodopsin II is the major photoproduct involved. Eur J Biochem. 1982 Sep;127(1):97–103. doi: 10.1111/j.1432-1033.1982.tb06842.x. [DOI] [PubMed] [Google Scholar]
- Cooper A. Rhodopsin photoenergetics: lumirhodopsin and the complete energy profile. FEBS Lett. 1981 Jan 26;123(2):324–326. doi: 10.1016/0014-5793(81)80319-5. [DOI] [PubMed] [Google Scholar]
- Emeis D., Kühn H., Reichert J., Hofmann K. P. Complex formation between metarhodopsin II and GTP-binding protein in bovine photoreceptor membranes leads to a shift of the photoproduct equilibrium. FEBS Lett. 1982 Jun 21;143(1):29–34. doi: 10.1016/0014-5793(82)80266-4. [DOI] [PubMed] [Google Scholar]
- HUBBARD R., ST GEORGE R. C. The rhodopsin system of the squid. J Gen Physiol. 1958 Jan 20;41(3):501–528. doi: 10.1085/jgp.41.3.501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hamdorf K., Razmjoo S. The prolonged depolarizing afterpotential and its contribution to the understanding of photoreceptor function. Biophys Struct Mech. 1977 Jun 29;3(2):163–170. doi: 10.1007/BF00535813. [DOI] [PubMed] [Google Scholar]
- Hillman P., Hochstein S., Minke B. Transduction in invertebrate photoreceptors: role of pigment bistability. Physiol Rev. 1983 Apr;63(2):668–772. doi: 10.1152/physrev.1983.63.2.668. [DOI] [PubMed] [Google Scholar]
- Kühn H., Hall S. W., Wilden U. Light-induced binding of 48-kDa protein to photoreceptor membranes is highly enhanced by phosphorylation of rhodopsin. FEBS Lett. 1984 Oct 29;176(2):473–478. doi: 10.1016/0014-5793(84)81221-1. [DOI] [PubMed] [Google Scholar]
- Liebman P. A., Pugh E. N., Jr ATP mediates rapid reversal of cyclic GMP phosphodiesterase activation in visual receptor membranes. Nature. 1980 Oct 23;287(5784):734–736. doi: 10.1038/287734a0. [DOI] [PubMed] [Google Scholar]
- Lisman J. E., Brown J. E. Light-induced changes of sensitivity in Limulus ventral photoreceptors. J Gen Physiol. 1975 Oct;66(4):473–488. doi: 10.1085/jgp.66.4.473. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lisman J. The role of metarhodopsin in the generation of spontaneous quantum bumps in ultraviolet receptors of Limulus median eye. Evidence for reverse reactions into an active state. J Gen Physiol. 1985 Feb;85(2):171–187. doi: 10.1085/jgp.85.2.171. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Minke B., Wu C., Pak W. L. Induction of photoreceptor voltage noise in the dark in Drosophila mutant. Nature. 1975 Nov 6;258(5530):84–87. doi: 10.1038/258084a0. [DOI] [PubMed] [Google Scholar]
- Nolte J., Brown J. E. Electrophysiological properties of cells in the median ocellus of Limulus. J Gen Physiol. 1972 Feb;59(2):167–185. doi: 10.1085/jgp.59.2.167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nolte J., Brown J. E. Ultraviolet-induced sensitivity to visible light in ultraviolet receptors of Limulus. J Gen Physiol. 1972 Feb;59(2):186–200. doi: 10.1085/jgp.59.2.186. [DOI] [PMC free article] [PubMed] [Google Scholar]
- O'Tousa J. E., Baehr W., Martin R. L., Hirsh J., Pak W. L., Applebury M. L. The Drosophila ninaE gene encodes an opsin. Cell. 1985 Apr;40(4):839–850. doi: 10.1016/0092-8674(85)90343-5. [DOI] [PubMed] [Google Scholar]
- Paulsen R., Hoppe I. Light-activated phosphorylation of cephalopod rhodopsin. FEBS Lett. 1978 Dec 1;96(1):55–58. doi: 10.1016/0014-5793(78)81061-8. [DOI] [PubMed] [Google Scholar]
- Saibil H. R., Michel-Villaz M. Squid rhodopsin and GTP-binding protein crossreact with vertebrate photoreceptor enzymes. Proc Natl Acad Sci U S A. 1984 Aug;81(16):5111–5115. doi: 10.1073/pnas.81.16.5111. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sitaramayya A., Liebman P. A. Mechanism of ATP quench of phosphodiesterase activation in rod disc membranes. J Biol Chem. 1983 Jan 25;258(2):1205–1209. [PubMed] [Google Scholar]
- Vandenberg C. A., Montal M. Light-regulated biochemical events in invertebrate photoreceptors. 1. Light-activated guanosinetriphosphatase, guanine nucleotide binding, and cholera toxin catalyzed labeling of squid photoreceptor membranes. Biochemistry. 1984 May 22;23(11):2339–2347. doi: 10.1021/bi00306a003. [DOI] [PubMed] [Google Scholar]
- Wilden U., Hall S. W., Kühn H. Phosphodiesterase activation by photoexcited rhodopsin is quenched when rhodopsin is phosphorylated and binds the intrinsic 48-kDa protein of rod outer segments. Proc Natl Acad Sci U S A. 1986 Mar;83(5):1174–1178. doi: 10.1073/pnas.83.5.1174. [DOI] [PMC free article] [PubMed] [Google Scholar]