Abstract
THE unicellular alga Chlamydomonas reinhardtii responds to weak flashes of light by changing its swimming direction and to brighter flashes with transient backward swimming (the stop or phobic response)1,2. In continuous light the cells swim towards or away from the light source (phototaxis)3,4. This behaviour is controlled by a visual system with a rhodopsin as the functional photoreceptor5,6. Physiological experiments under different ionic conditions have suggested that ionic processes are involved in the signal transduction from the photoreceptor to the flagella1,2,4. Here we show by ion current measurements that there are two distinct light-regulated inward currents which are localized in the eyespot and in the flagellar region of the cell. From the kinetics and the rhodopsin action spectrum of these photocurrents we conclude that they are part of the rhodopsin-regulated signal transduction chain controlling the cellular behaviour in light. Both photocurrents are Ca2+-dependent and are suppressed by the Ca2+-channel inhibitors verapamil and pimozide, suggesting that the photoreceptor current and probably the flagellar current are both carried by Ca2+.
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References
Schmidt, I. A. & Eckert, R. Nature 262, 713–715 (1976).
Hegemann, P. & Bruck, B. Cell Motil. 14, 401–515 (1989).
Pfeffer, W. Pflanzenphysiologie (Engelmann, Leipzig, 1904).
Nultsch, W. & Häder, D.-P. Photochem. Photobiol. 47, 837–869 (1987).
Foster, K. W. et al. Nature 311, 765–715 (1984).
Beckmann, M. & Hegemann, P. Biochemistry 30, 3692–3697 (1991).
Baylor, D. A., Lamb, T. D. & Yau, K.-W. J. Physiol. 288, 589–611 (1979).
Litvin, F. F., Sineshchekov, O. A. & Sineshchekov, V. A. Nature 271, 476–478 (1978).
Foster, K. W. & Smyth, R. D. Microbiol. Rev. 44, 572–636 (1980).
Uhl, R. & Hegemann, P. Biophys. J. 58, 1295–1302 (1990).
Glossmann, H. & Striessnig, J. Vitamins Hormones 44, 155–328 (1988).
Nultsch, W., Pfau, J. & Dolle, R. Arch. Microbiol. 144, 393–397 (1986).
Hegemann, P., Neumeier, K., Hegemann, U. & Kühnle, E. Photochem. Photobiol. 52, 575–579 (1990).
Morse, M. J., Crain, R. C. & Satter, R. L. Proc. natn. Acad. Sci. U.S.A. 84, 7075–7078 (1987).
Ettlinger, C. & Lehle, L. Nature 331, 176–178 (1988).
Schilde, C. Z. Naturforschung 236, 1369–1376 (1968).
Gradmann, D. J. Membr. Biol. 44, 1–24 (1978).
Sineshchekov, O. A., Litvin, F. F. & Keszthelyi, L. Biophys. J. 57, 33–39 (1990).
Kamiya, R. & Witman, G. J. Cell Biol. 98, 97–107 (1984).
Kung, C. & Saimi, Y. A. Rev. Physiol. 44, 519–34 (1982).
Hegemann, P., Hegemann, U. & Foster, K. W. Photochem. Photobiol. 48, 123–128 (1988).
Tsien, R. Y. Biochemistry 19, 2396–2404 (1980).
Knowles, A. & Dartnall, H. J. in The Eye Vol. 2B (ed. Davison, H.) 76 (Academic, New York, 1977).
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Harz, H., Hegemann, P. Rhodopsin-regulated calcium currents in Chlamydomonas. Nature 351, 489–491 (1991). https://doi.org/10.1038/351489a0
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DOI: https://doi.org/10.1038/351489a0
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