Kefalov Lab

Vladimir Kefalov, PhD, Professor, Ophthalmology and Visual Sciences

Research

We derive most of our information about the world through our visual system by means of rod and cone photoreceptors. The human retina has one type of rod for dim light vision, and three types of cone cells that allow color discrimination. Despite the similarities in their morphology and mechanism of light detection, rods and cones have distinct functional properties. Rods are extremely sensitive (they can detect a single photon of light!) and thus are perfectly suited for dim light conditions. They saturate in moderate light, however, and are not able to respond to light through most of the day. Cones, on the other hand, are 30-100 times less sensitive than rods and do not respond to light in dim light conditions (this is why we don’t see colors at night). However, cones are capable of adapting to an extremely wide range of light conditions, rendering them perfectly suited as our daytime photoreceptors. Our lab is interested in the mechanisms that determine the functional properties of mammalian rod and cone photoreceptors. We use a battery of tools, from single-cell and isolated retina recordings, to live electroretinogram and behavior experiments with wild type and genetically modified mice. While the emphasis of our studies is on our daytime photoreceptors, the cones, we are also investigating some aspects of rod phototransduction. Some of the ongoing projects in the lab are:

Rod & Cone Suction Recordings

Cone Pigment Cyle

Publications

2016

  • Razafsky D., Ward C., Potter C., Zhu W., Xue Y., Kefalov V.J., Fong L.G., Young S.G., Hodzic D. (2016) Lamin B1 and lamin B2 are long-lived proteins with distinct functions in retinal development. Mol Biol Cell 27:1928-37. PDF
  • Frederiksen R., Nymark S., Kolesnikov A.V., Berry J.D., Adler L., Koutalos Y., Kefalov V.J., Cornwall M.C. (2016) Rhodopsin kinase and arrestin binding control the decay of photoactivated rhodopsin and dark adaptation of mouse rods. J Gen Physiol. 148:1-11.Sato S, Kefalov VJ. (2016) PDF
  • SatoS., Kefalov V.J. cis Retinol oxidation regulates photoreceptor access to the retina visual cycle and cone pigment regeneration. J Physiol. 594:6753-6765. PDF
  • Sakurai K., Vinberg F., Wang T., Chen J., Kefalov V.J. (2016) The Na+/Ca2+, K+ exchanger 2 modulates mammalian cone phototransduction. Sci Rep 6:32521. doi: 10.1038/srep32521. PDF

In the Media

Find out more about our research from recent press, podcast, and video coverage:

Vacancies

Postdoctoral Position Available

An NIH-funded postdoctoral position is available immediately to study the physiological properties of mammalian photoreceptors. We are seeking an energetic, highly motivated PhD, MD, or MD/PhD with solid publication record and vision research-related experience in neuroscience, electrophysiology, biophysics, or biochemistry. Experience in molecular biology is a plus and good analytical and communication skills are essential. The specific project will be tailored to the interests and qualifications of the applicant, but will focus broadly on using electrophysiological tools to study the phototransduction cascade, adaptation, and the visual cycle of mammalian photoreceptors, and their link to retinal degeneration and visual disorders. For details on recent research click the publications tab. The successful candidate will have access to state-of-the-art lab equipment and departmental core facilities, as well as to the great research community in one of the top medical schools in the USA. To apply, please email cover letter, curriculum vitae, and list of references to: Dr. Vladimir Kefalov (kefalov@vision.wustl.edu), Ophthalmology & Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave, Box 8096, Saint Louis, MO 63110.

Student Position Available

We are always happy to welcome bright and motivated students. We are a small but rather productive and collaborative lab that offers friendly and supportive environment for mastering the art of visual neuroscience and photoreceptor electrophysiology. Funding is available for selected students dissertation research. Please contact Vladimir if you are interested in discussing a rotation in the lab.