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. 1995 Nov;69(5):2163–2167. doi: 10.1016/S0006-3495(95)80090-1

Diffusion coefficient of the cyclic GMP analog 8-(fluoresceinyl)thioguanosine 3',5' cyclic monophosphate in the salamander rod outer segment.

Y Koutalos 1, R L Brown 1, J W Karpen 1, K W Yau 1
PMCID: PMC1236450  PMID: 8580360

Abstract

Cyclic GMP (cGMP) is the intracellular messenger mediating phototransduction in retinal rods, with its longitudinal diffusion in the rod outer segment (ROS) likely to be a factor in determining light sensitivity. From the kinetics of cGMP-activated currents in the truncated ROS of the salamander (Ambystoma tigrinum), the cGMP diffusion coefficient was previously estimated to be approximately 60 x 10(-8) cm2 s-1. On the other hand, fluorescence measurements in intact salamander ROS using 8-(fluoresceinyl)thioguanosine 3',5'-cyclic monophosphate (Fl-cGMP) led to a diffusion coefficient for this compound of 1 x 10(-8) cm2 s-1; after corrections for differences in size and in binding to cellular components between cGMP and Fl-cGMP, this gave an upper limit of 11 x 10(-8) cm2 s-1 for the cGMP diffusion coefficient. To properly compare the two sets of measurements, we have examined the diffusion of Fl-cGMP in the truncated ROS. From the kinetics of Fl-cGMP-activated currents, we have obtained a diffusion coefficient of 3 x 10(-8) cm2 s-1 for this analog; the cGMP diffusion coefficient measured from the same truncated ROSs was approximately 80 x 10(-8) cm2 s-1. Thus, a factor of 27 appears appropriate for correcting differences in size and intracellular binding between cGMP and Fl-cGMP. Application of this correction factor to the Fl-cGMP diffusion coefficient measurements by Olson and Pugh (1993) gives a cGMP diffusion coefficient of approximately 30 x 10(-8) cm2 s-1, in reasonable agreement with the value measured from the truncated ROS.

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Selected References

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  1. BOWEN W. J., MARTIN H. L. THE DIFFUSION OF ADENOSINE TRIPHOSPHATE THROUGH AQUEOUS SOLUTIONS. Arch Biochem Biophys. 1964 Jul;107:30–36. doi: 10.1016/0003-9861(64)90265-6. [DOI] [PubMed] [Google Scholar]
  2. Baylor D. A., Lamb T. D., Yau K. W. Responses of retinal rods to single photons. J Physiol. 1979 Mar;288:613–634. [PMC free article] [PubMed] [Google Scholar]
  3. Blaurock A. E., Wilkins M. H. Structure of frog photoreceptor membranes. Nature. 1969 Aug 30;223(5209):906–909. doi: 10.1038/223906a0. [DOI] [PubMed] [Google Scholar]
  4. Brown R. L., Bert R. J., Evans F. E., Karpen J. W. Activation of retinal rod cGMP-gated channels: what makes for an effective 8-substituted derivative of cGMP? Biochemistry. 1993 Sep 28;32(38):10089–10095. doi: 10.1021/bi00089a026. [DOI] [PubMed] [Google Scholar]
  5. Caillé J. P., Hinke J. A. The volume available to diffusion in the muscle fiber. Can J Physiol Pharmacol. 1974 Aug;52(4):814–828. doi: 10.1139/y74-107. [DOI] [PubMed] [Google Scholar]
  6. Caretta A., Cavaggioni A., Sorbi R. T. Binding stoichiometry of a fluorescent cGMP analogue to membranes of retinal rod outer segments. Eur J Biochem. 1985 Nov 15;153(1):49–53. doi: 10.1111/j.1432-1033.1985.tb09265.x. [DOI] [PubMed] [Google Scholar]
  7. Detwiler P. B., Gray-Keller M. P. Some unresolved issues in the physiology and biochemistry of phototransduction. Curr Opin Neurobiol. 1992 Aug;2(4):433–438. doi: 10.1016/0959-4388(92)90176-l. [DOI] [PubMed] [Google Scholar]
  8. Kao H. P., Abney J. R., Verkman A. S. Determinants of the translational mobility of a small solute in cell cytoplasm. J Cell Biol. 1993 Jan;120(1):175–184. doi: 10.1083/jcb.120.1.175. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Karpen J. W., Zimmerman A. L., Stryer L., Baylor D. A. Gating kinetics of the cyclic-GMP-activated channel of retinal rods: flash photolysis and voltage-jump studies. Proc Natl Acad Sci U S A. 1988 Feb;85(4):1287–1291. doi: 10.1073/pnas.85.4.1287. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Korenbrot J. I., Brown D. T., Cone R. A. Membrane characteristics and osmotic behavior of isolated rod outer segments. J Cell Biol. 1973 Feb;56(2):389–398. doi: 10.1083/jcb.56.2.389. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Koutalos Y., Nakatani K., Yau K. W. Cyclic GMP diffusion coefficient in rod photoreceptor outer segments. Biophys J. 1995 Jan;68(1):373–382. doi: 10.1016/S0006-3495(95)80198-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Koutalos Y., Yau K. W. A rich complexity emerges in phototransduction. Curr Opin Neurobiol. 1993 Aug;3(4):513–519. doi: 10.1016/0959-4388(93)90049-5. [DOI] [PubMed] [Google Scholar]
  13. Kushmerick M. J., Podolsky R. J. Ionic mobility in muscle cells. Science. 1969 Dec 5;166(3910):1297–1298. doi: 10.1126/science.166.3910.1297. [DOI] [PubMed] [Google Scholar]
  14. Lagnado L., Baylor D. Signal flow in visual transduction. Neuron. 1992 Jun;8(6):995–1002. doi: 10.1016/0896-6273(92)90122-t. [DOI] [PubMed] [Google Scholar]
  15. Lamb T. D., McNaughton P. A., Yau K. W. Spatial spread of activation and background desensitization in toad rod outer segments. J Physiol. 1981;319:463–496. doi: 10.1113/jphysiol.1981.sp013921. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Nakatani K., Yau K. W. Calcium and magnesium fluxes across the plasma membrane of the toad rod outer segment. J Physiol. 1988 Jan;395:695–729. doi: 10.1113/jphysiol.1988.sp016942. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Olson A., Pugh E. N., Jr Diffusion coefficient of cyclic GMP in salamander rod outer segments estimated with two fluorescent probes. Biophys J. 1993 Sep;65(3):1335–1352. doi: 10.1016/S0006-3495(93)81177-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Pugh E. N., Jr, Lamb T. D. Amplification and kinetics of the activation steps in phototransduction. Biochim Biophys Acta. 1993 Mar 1;1141(2-3):111–149. doi: 10.1016/0005-2728(93)90038-h. [DOI] [PubMed] [Google Scholar]
  19. Rosenkranz J. New aspects of the ultrastructure of frog rod outer segments. Int Rev Cytol. 1977;50:25–158. doi: 10.1016/s0074-7696(08)60098-4. [DOI] [PubMed] [Google Scholar]
  20. SIDMAN R. L. The structure and concentration of solids in photoreceptor cells studied by refractometry and interference microscopy. J Biophys Biochem Cytol. 1957 Jan 25;3(1):15–30. doi: 10.1083/jcb.3.1.15. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Tanaka J. C., Eccleston J. F., Furman R. E. Photoreceptor channel activation by nucleotide derivatives. Biochemistry. 1989 Apr 4;28(7):2776–2784. doi: 10.1021/bi00433a006. [DOI] [PubMed] [Google Scholar]
  22. Yarfitz S., Hurley J. B. Transduction mechanisms of vertebrate and invertebrate photoreceptors. J Biol Chem. 1994 May 20;269(20):14329–14332. [PubMed] [Google Scholar]
  23. Yau K. W. Phototransduction mechanism in retinal rods and cones. The Friedenwald Lecture. Invest Ophthalmol Vis Sci. 1994 Jan;35(1):9–32. [PubMed] [Google Scholar]

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