Molecular physiology of visual pigment rhodopsin

The key physiological functions of the rhodopsin molecule are reviewed. Molecular mechanisms of visual pigments spectral tuning, photoisomerization of the 11-cis-retinal chromophore that triggers the phototransduction process, formation of physiologically active state of rhodopsin as a G-protein-coupled receptor, rhodopsin visual cycle, and consequences of its impairment are evaluated. Visual pigment rhodopsin performs several functions, providing spectral sensitivity of photoreceptor cells, phototransduction processes and light and dark adaptation. Genetically determined defects of visual pigment molecule and proteins involved into mechanisms of phototransduction and adaptation or into mechanism of visual cycle are directly linked to pathogenesis of different forms of degenerative retina diseases. Understanding the molecular mechanisms of these physiological processes uncovers the way to direct investigation of pathogenesis of these severe eye diseases.