Melanopsin-mediated light-sensing in amphioxus
نویسندگان
چکیده
منابع مشابه
Light-transduction in melanopsin-expressing photoreceptors of Amphioxus.
Spatial vision in different organisms is mediated by 2 classes of photoreceptors: microvillar and ciliary. Recently, additional photosensitive cells implicated in nonvisual light-dependent functions have been identified in the mammalian retina. A previously undescribed photopigment, melanopsin, underlies these photoresponses, and it has been proposed that its transduction mechanisms may be akin...
متن کاملCalcium activates the light-dependent conductance in melanopsin-expressing photoreceptors of amphioxus.
Melanopsin, the photopigment of the "circadian" receptors that regulate the biological clock and the pupillary reflex in mammals, is homologous to invertebrate rhodopsins. Evidence supporting the involvement of phosphoinositides in light-signaling has been garnered, but the downstream effectors that control the light-dependent conductance remain unknown. Microvillar photoreceptors of the primit...
متن کاملThe light-sensitive conductance of melanopsin-expressing Joseph and Hesse cells in amphioxus
Two types of microvillar photoreceptors in the neural tube of amphioxus, an early chordate, sense light via melanopsin, the same photopigment as in "circadian" light detectors of higher vertebrates. Because in amphioxus melanopsin activates a G(q)/phospholipase C cascade, like phototransduction in arthropods and mollusks, possible commonalities in the photoconductance were investigated. Unlike ...
متن کاملDissecting the determinants of light sensitivity in amphioxus microvillar photoreceptors: possible evolutionary implications for melanopsin signaling.
Melanopsin, a photopigment related to the rhodopsin of microvillar photoreceptors of invertebrates, evolved in vertebrates to subserve nonvisual light-sensing functions, such as the pupillary reflex and entrainment of circadian rhythms. However, vertebrate circadian receptors display no hint of a microvillar specialization and show an extremely low light sensitivity and sluggish kinetics. Recen...
متن کاملMelanopsin-Expressing Amphioxus Photoreceptors Transduce Light via a Phospholipase C Signaling Cascade
Melanopsin, the receptor molecule that underlies light sensitivity in mammalian 'circadian' receptors, is homologous to invertebrate rhodopsins and has been proposed to operate via a similar signaling pathway. Its downstream effectors, however, remain elusive. Melanopsin also expresses in two distinct light-sensitive cell types in the neural tube of amphioxus. This organism is the most basal ex...
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ژورنال
عنوان ژورنال: Communicative & Integrative Biology
سال: 2009
ISSN: 1942-0889
DOI: 10.4161/cib.2.5.9244