title: Not just signal shutoff: the protective role of arrestin-1 in rod cells.
abstract: The retinal rod cell is an exquisitely sensitive single-photon detector that primarily functions in dim light (e.g., moonlight). However, rod cells must routinely survive light intensities more than a billion times greater (e.g., bright daylight). One serious challenge to rod cell survival in daylight is the massive amount of all-trans-retinal that is released by Meta II, the light-activated form of the photoreceptor rhodopsin. All-trans-retinal is toxic, and its condensation products have been implicated in disease. Our recent work has developed the concept that rod arrestin (arrestin-1), which terminates Meta II signaling, has an additional role in protecting rod cells from the consequences of bright light by limiting free all-trans-retinal. In this chapter we will elaborate upon the molecular mechanisms by which arrestin-1 serves as both a single-photon response quencher as well as an instrument of rod cell survival in bright light. This discussion will take place within the framework of three distinct functional modules of vision: signal transduction, the retinoid cycle, and protein translocation.
authors.affiliation: Institut für Medizinische Physik und Biophysik (CC2), Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany, martha.sommer@charite.de.
authors.forename: Martha E
authors.initials: ME
authors.lastname: Sommer
authors.forename: Klaus Peter
authors.initials: KP
authors.lastname: Hofmann
authors.forename: Martin
authors.initials: M
authors.lastname: Heck
mesh_terms: D000818:Animals; D019393:Arrestin / Q000378:metabolism*; D006801:Humans; D008027:Light; D010766:Phosphorylation; D021381:Protein Transport / Q000502:physiology; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D012176:Retinoids / Q000502:physiology; D012243:Rhodopsin / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D019393:Arrestin; D012176:Retinoids; C013110:metarhodopsins; D012243:Rhodopsin