title: Detecting single photons: a supramolecular matter?
abstract: Rod photoreceptors detect single photons through a tradeoff of light collecting ability, amplification and speed. Key roles are played by rhodopsin (Rh) and transducin (G(t)), whose complex supramolecular organization in outer segment disks begs for a functional interpretation. Here we review past and recent evidence of a temperature-dependence of photon detection by mammalian rods, and link this phenomenon with the putative oligomeric organization of Rh and new ideas on the dynamics of Rh-G(t) interaction. Identifying an electrophysiological correlate of the supramolecular organization of Rh and G(t) may shed light on the evolutionary advantage it confers to night vision.
authors.affiliation: Dip. di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Università di Pisa, Via San Zeno 31, 56123 Pisa, Italy. lorenzo.cangiano@gmail.com
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cangiano
authors.forename: Daniele
authors.initials: D
authors.lastname: Dell'Orco
mesh_terms: D000818:Animals; D055724:Electrophysiological Phenomena; D006801:Humans; D055254:Night Vision; D017785:Photons; D055214:Retinal Photoreceptor Cell Outer Segment / Q000378:metabolism*; D012243:Rhodopsin / Q000378:metabolism*; D013696:Temperature; D015293:Transducin / Q000378:metabolism*; D014795:Visual Pathways / Q000378:metabolism
chemical_list: D012243:Rhodopsin; D015293:Transducin