Role of visual pigment properties in rod and cone phototransduction

Vladimir Kefalov, Yingbin Fu, Nicholas Marsh-Armstrong, King Wai Yau

Research output: Contribution to journalArticle

96 Citations (Scopus)

Abstract

Retinal rods and cones share a phototransduction pathway involving cylic GMP. Cones are typically 100 times less photosensitive than rods and their response kinetics are several times faster, but the underlying mechanisms remain largely unknown. Almost all proteins involved in phototransduction have distinct rod and cone variants. Differences in properties between rod and cone pigments have been described, such as a 10-fold shorter lifetime of the meta-II state (active conformation) of cone pigment and its higher rate of spontaneous isomerization, but their contributions to the functional differences between rods and cones remain speculative. We have addressed this question by expressing human or salamander red cone pigment in Xenopus rods, and human rod pigment in Xenopus cones. Here we show that rod and cone pigments when present in the same cell produce light responses with identical amplification and kinetics, thereby ruling out any difference in their signalling properties. However, red cone pigment isomerizes spontaneously 10,000 times more frequently than rod pigment. This high spontaneous activity adapts the native cones even in darkness, making them less sensitive and kinetically faster than rods. Nevertheless, additional factors are probably involved in these differences.

Original languageEnglish (US)
Pages (from-to)526-531
Number of pages6
JournalNature
Volume425
Issue number6957
DOIs
StatePublished - Oct 2 2003
Externally publishedYes

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Light Signal Transduction
Vertebrate Photoreceptor Cells
Retinal Pigments
Xenopus
Retinal Cone Photoreceptor Cells
Retinal Rod Photoreceptor Cells
Urodela
Darkness
Light
Proteins

ASJC Scopus subject areas

  • General

Cite this

Role of visual pigment properties in rod and cone phototransduction. / Kefalov, Vladimir; Fu, Yingbin; Marsh-Armstrong, Nicholas; Yau, King Wai.

In: Nature, Vol. 425, No. 6957, 02.10.2003, p. 526-531.

Research output: Contribution to journalArticle

Kefalov, Vladimir ; Fu, Yingbin ; Marsh-Armstrong, Nicholas ; Yau, King Wai. / Role of visual pigment properties in rod and cone phototransduction. In: Nature. 2003 ; Vol. 425, No. 6957. pp. 526-531.
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