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Storm Eye Photoreceptors





Department of Ophthalmology


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Yiannis Koutalos, Ph.D.

B.S. Physics, University of Athens, 1984
Ph.D. Biophysics, University of Illinois, 1991

Storm Eye Institute, Room 712
Tel:     843-792-9180
Fax:     843-792-1723


Research Interests

My research studies the physiology of photoreceptor cells, the sensory neurons that convert light into an electrical signal.  The detection of light by these cells involves the formation of waste byproducts that need to be eliminated.  I am interested in the generation and clearance of these byproducts, as well as in their effects on cell function.  Impairment of waste removal underlies a variety of retinal diseases, including Age-related Macular Degeneration, Stargardt’s disease, and some forms of Retinitis Pigmentosa.   Age-related Macular Degeneration is the leading cause of blindness in industrialized countries.  Stargardt’s disease and Retinitis Pigmentosa are hereditary diseases.  Stargardt’s Disease affects one in 10,000 people, while Retinitis Pigmentosa affects one in 3,000 people.

We use fluorescence imaging to visualize and measure the formation, removal, and the deleterious effects of these toxic byproducts in living photoreceptor cells in real time.  A more detailed presentation can be found under Research.

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Representative Publications

Chen C, Thompson DA and Koutalos Y.  Reduction of all-trans retinal in vertebrate rod photoreceptors requires the combined action of RDH8 and RDH12.  J Biol Chem 287:24662–24670. 2012.

Boyer NP, Higbee D, Currin MB, Blakeley LR, Chen C, Ablonczy Z, Crouck RK and Koutalos Y.  Lipofuscin and N-retinylidene-N-retinylethanolamine (A2E) Accumulate in the Retinal Pigment Epithelium in the Absence of Light Exposure:  Their Origin is 11-cis-Retinal.  J Biol Chem 287:22276-22286. 2012.

Chen C, Blakeley LR and Koutalos Y.  Formation of all-trans retinol after visual pigment bleaching in mouse photoreceptors.  Invest Ophthalmol Vis Sci 50:3589-3595. 2009.

Wu Q, Chen C and Koutalos Y. All-trans retinol in rod photoreceptor outer segments moves unrestrictedly by passive diffusion. Biophys J 91:4678-4689. 2006.

Chen C, Nakatani K and Koutalos Y. Free magnesium concentration in salamander photoreceptor outer segments. J Physiol 553:125-135. 2003.

Chen C, Nakamura T and Koutalos Y. Cyclic AMP diffusion coefficient in frog olfactory cilia. Biophys J 76:2861-2867. 1999.

Koutalos Y and Yau KW. Regulation of sensitivity in vertebrate rod photoreceptors by calcium. Trends Neurosci 19:73-81. 1996.

Koutalos Y, Ebrey TG, Gilson HR and Honig B. Octopus photoreceptor membranes. Surface charge density and pK of the Schiff base of the pigments. Biophys J 58:493-501. 1990.

Koutalos Y, Ebrey TG, Tsuda M, Odashima K, Lien T, Park MH, Shimizu N, Derguini F, Nakanishi K, Gilson HR and Honig B. Regeneration of bovine and octopus opsins in situ with natural and artificial retinals. Biochemistry 28:2732-2739. 1989.

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