title: Ca(2+) sensor GCAP1: A constitutive element of the ONE-GC-modulated odorant signal transduction pathway.
abstract: In a small subset of the olfactory sensory neurons, the odorant receptor ONE-GC guanylate cyclase is a central transduction component of the cyclic GMP signaling pathway. In a two-step transduction model, the odorant, uroguanylin, binds to the extracellular domain and activates its intracellular domain to generate the odorant second messenger, cyclic GMP. This study via comprehensive technology, including gene deletion, live cell Forster resonance energy transfer (FRET), and surface plasmon resonance (SPR) spectroscopy, documents the identity of a remarkably intriguing operation of a Ca(2+) sensor component of the ONE-GC transduction machinery, GCAP1. In the ciliary membranes, the sites of odorant transduction, GCAP1 is biochemically and physiologically coupled to ONE-GC. Strikingly, this coupling reverses its well- established function in ROS-GC1 signaling, linked with phototransduction. In response to the free Ca(2+) range from nanomolar to semimicromolar, it inhibits ROS-GC1, yet in this range, it incrementally stimulates ONE-GC. These two opposite modes of signaling two SENSORY processes by a single Ca(2+) sensor define a new transduction paradigm of membrane guanylate cyclases. This paradigm is pictorially presented.
authors.affiliation: Research Division of Biochemistry, The Unit of Regulatory and Molecular Biology, Salus University, Elkins Park, Pennsylvania 19027, USA.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Pertzev
authors.forename: Teresa
authors.initials: T
authors.lastname: Duda
authors.forename: Rameshwar K
authors.initials: RK
authors.lastname: Sharma
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D004602:Elements; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D055537:Light Signal Transduction; D045265:Natriuretic Peptides; D009812:Odorants; D015290:Second Messenger Systems; D011984:Sensory Receptor Cells; D015398:Signal Transduction
chemical_list: D004602:Elements; D045265:Natriuretic Peptides; C084362:uroguanylin; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D002118:Calcium