| Popis: |
Life has evolved under consistent patterns of light and dark due to the constant rotation of Earth as it revolves around its nearest star. Organisms are bathed in this electromagnetic radiation as it scatters through the atmosphere and off nearby objects. Animals have evolved to detect these photons for adaptive advantage through a family of unique G protein-coupled receptors known as opsins. Opsins conjugate to a chromophore, retinal, to convert energy from incident photons into a biological signal. This process allows animals to see as well as to synchronize their physiology to daily and seasonal rhythms. While the retina is a specialized tissue packed full of these opsin proteins for functions such as vision, these genes are found throughout the body. Extraocular opsins function in a variety of diverse processes, including in the regulation of metabolism, body temperature, feeding behavior, smooth muscle relaxation, and pigmentation.The opsin proteins can be largely classified into three groups: the visual opsins (rhodopsin, cone opsins), photoisomerases (RGR-opsin and peropsin), and the atypical opsins (encephalopsin, melanopsin, neuropsin). This latter group, the atypical opsins, are commonly found in extraretinal tissue. While melanopsin has been well studied, little has been known about the other atypical opsins until recently. This thesis will describe several ways in which the atypical opsins, encephalopsin and neuropsin, shape mammalian physiology. |
