Molecular mechanism of visual transduction.

  title={Molecular mechanism of visual transduction.},
  author={Krzysztof Palczewski and Christophe L. M. J. Verlinde and Françoise Haeseleer},
  journal={Novartis Foundation symposium},
          191-204; discussion 204-7
Our vision renders an incredible wealth of information about the external environment presented in the form of light of different wavelengths and intensities. To operate in a wide range of light intensities, our visual system has developed several mechanisms that allow an adjustment of its sensitivity to light. Immense progress has been made in understanding how light is captured and activates visual phototransduction cascade within photoreceptor cells; however, much less is known about… 


How photons start vision.
  • D. Baylor
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1996
Physiological methods are used to study the molecular mechanisms that terminate the flash response and mediate adaptation in the cGMP cascade, causing the single photon response to be reproducible and allowing the cell to adapt in background light.
Molecular mechanism of light-adaptation in retinal photoreceptors.
The generation mechanism of the photoresponse, namely the phototransduction mechanism is now well characterized, and light-induced decrease in the cytoplasmic [Ca2+] plays a major role.
Null mutation in the rhodopsin kinase gene slows recovery kinetics of rod and cone phototransduction in man.
In this human in vivo condition without a functional RK and probable lack of phosphorylation and arrestin binding to activated rhodopsin, reduction of photolyzed chromophore and regeneration processes with 11-cis-retinal probably constitute the sole pathway for recovery of rod sensitivity.
Recoverin: a calcium sensitive activator of retinal rod guanylate cyclase
Vertebrate retinal photoreceptors recover from photoexcitation-induced hydrolysis of guanosine 3', 5'-monophosphate (cyclic GMP) by resynthesizing cyclic GMP, which reopens cation channels that have
Functional reconstitution of photoreceptor guanylate cyclase with native and mutant forms of guanylate cyclase-activating protein 1.
It is shown that N-acylated GCAP1 restored Ca2+ sensitivity of native and recombinant photoreceptor retGC1 and suggested that the N-terminal region is important in tethering of GC AP1 to the ROS membranes.
Constitutive Activation of Photoreceptor Guanylate Cyclase by Y99C Mutant of GCAP-1
It is found that the Y99C GCAP-1 can activate RetGC even in the presence of Ca2+-loaded nonmutant GCAPs, consistent with the fact that cone degeneration was dominant in human patients who carried such mutation.
Guanylyl Cyclase Activating Protein
It is demonstrated that GCAP1 is an activator of ROS GC, while the finding of a second activator, GCAP2, suggests that a similar mechanism of GC regulation may be present in outer segments, other subcellular compartments of the photoreceptor, or other cell types.