Membrane Assembly in Retinal Photoreceptors III

Total Page:16

File Type:pdf, Size:1020Kb

Membrane Assembly in Retinal Photoreceptors III 0270.6474/E/0504-1035$02.00/O The Journal of Neuroscience CopyrIght 0 Society for Neuroscience Vol. 5. No. 4, pp. 1035-1048 Printed m U.S.A. April 1985 Membrane Assembly in Retinal Photoreceptors III. Distinct Membrane Domains of the Connecting Cilium of Developing Rods’ JOSEPH C. BESHARSE,2 DONNA M. FORESTNER, AND DENNIS M. DEFOE Department of Anatomy, Emory University School of Medicine, Atlanta, Georgia 30322 Abstract Retinal photoreceptors provide a unique opportunity for the study of neuronal polarity related to membrane turnover and the formation To investigate the putative role of the photoreceptor con- of functional membrane domains. The membranous rod outer seg- necting cilium in the delivery of opsin to forming discs and in ment @OS) consists of photosensitive discs surrounded by a plasma the maintenance of membrane domains (Besharse, J. C., and membrane and is connected to the cell body by a non-motile cilium K. H. Pfenninger (1980) J. Cell Biol. 87: 451-483), we have (Rohlich, 1975). The dominant intrinsic protein of the ROS is opsin, studied developing photoreceptors of neonatal rats during the apoprotein of visual pigment (Hall et al., 1969). Whereas opsin the period of initial disc formation using conventional freeze- is largely restricted to the ROS (Jan and Revel, 1974; Papermaster fracture, immunocytochemistry, and lectin cytochemistry. et al., 1978) an Na+/K+ ATPase responsible for generation of the Specific anti-opsin-binding sites were localized in the distal photoreceptor dark current (Hagins, 1972) is restricted to the inner cilium, the developing outer segment plasma membrane, and segment (Stirling and Lee, 1980). The zone of demarcation separat- at focal sites on the inner segment plasma membrane at all ing these distinctive membrane domains appears to be in the region developmental stages examined, including the period prior of the connecting cilium. to the onset of disc morphogenesis. The proximal ciliary Throughout life the ROS turns over by a process involving assem- shaft generally lacked anti-opsin-binding sites or exhibited bly of new discs from ciliary plasmalemma, their transport distally, them in extremely low density. The distribution of anti-opsin- and their eventual loss from the ROS distal tip (Young and Bok, binding sites corresponded in a general way to the distribu- 1969; Young, 1976). Opsin and other membrane components are tion of large intramembranous particles (IMPS) in freeze- synthesized in the inner segment, transported to the periciliary fracture replicas like those seen in the rod outer segment region, and rapidly consumed in the process of disc assembly (ROS). The proximal zone corresponded in freeze-fracture (Young, 1967; Young and Droz, 1968; Papermaster et al., 1975). images to a zone of consecutive horizontal rows of intramem- Opsin is a transmembrane glycoprotein (Fukuda et al., 1979; Har- brane particles (ciliary necklaces) and axoneme-membrane grave, 1982) that is initially synthesized on rough endoplasmic cross-linkers. Although protoplasmic face leaflet IMPS similar reticulum (RER) (Young and Droz, 1968; Hall et al., 1969). It is co- to those of the distal cilium and outer segment were less translationally inserted into RER membrane (Goldman and Blobel, abundant in the inner segment and proximal cilium than in 1981) and then transferred to the Golgi complex for further process- the distal cilium and ROS, they were detected in these zones ing prior to transport to the cilium (Papermaster et al., 1978). at low frequency. Cytochemistry with concanavalin A and Throughout its sojourn in the cell, opsin appears to be associated wheatgerm agglutinin revealed the presence of a well devel- with membranous organelles. A fundamental question for which only oped glycocalyx in the proximal zone. Although opsin binds both lectins, the results suggest heterogeneity among the provisional data are available relates to the mechanism of delivery and concentration of opsin in the ROS while maintaining the distinc- glycoconjugates of the three membrane domains. Our data define distinct membrane domains of the developing photo- tive properties of inner and outer segment membranes. receptor cilium that have important implications for the mech- Recent morphological, freeze-fracture, immunocytochemical, and anisms for delivering and sequestering opsin in the outer autoradiographic data (Holtzman et al., 1977; Kinney and Fisher, segment. They also establish that the mechanism of opsin 1978; Papermaster et al., 1979, 1985; Besharse and Pfenninger, delivery to the distal zone occurs well in advance of the 1980; Besharse and Forestner, 1981; Defoe and Besharse, 1985) period of disc morphogenesis. have identified a population of smooth membranous vesicles and cisternae in the periciliary region as the principal organelles of opsin transport to the site of disc assembly. The events occurring in the ciliary region that lead to disc morphogenesis are less well defined. Largely on the basis of freeze-fracture analysis we have suggested Received May 25, 1984; Revised October 22, 1984; that opsin-containing vesicles fuse with the inner segment plasma Accepted October 24, 1984 membrane near the cilium and that membrane components destined ’ Our hearty thanks to David Papermaster for a generous supply of for incorporation into discs are transferred to the disc-forming region antibody and to Win Sale for many useful discussions. This work was via the ciliary plasmalemma (Besharse and Pfenninger, 1980). The supported by National institutes of Health Research Grant EY03222, Re- elaborately developed periciliary ridge complex of frog photorecep- search Career Development Award EY00169 to J. C. B, and Postdoctoral tors may play a role in exocytotic fusion and shunting of components Fellowship EY05646 to D. M. D. Preliminary reports of these results have into the cilium (Andrews, 1982; Peters et al., 1983). Such a mecha- appeared in abstract form (Besharse and Forestner, 1983; Forestner and nism implies that the ciliary region is capable of concentrating Besharse, 1983). membrane components distally against a concentration gradient ’ To whom correspondence should be addressed. and restricting the lateral mobility of those components in order to 1035 1036 Besharse et al. Vol. 5, No. 4, Apr. 1985 The Journal of Neuroscience Membrane Domains of Connecting Cilium of Developing Rods 1037 maintain the distinctive characteristics of inner and outer segment used affinity-purified, biotinylated sheep anti-bovine opsin IgG at concentra- membranes. tions of 0.03 to 0.18 mg/ml as the first stage ligand. This antibody has been To analyze further the role of the cilium in these processes, we characterized extensively (Papermaster et al., 1978) and was generously have carried out a morphological analysis of the cilium of neonatal provided by Dr. David S. Papermaster. Purification was carried out with purified bovine opsin coupled to sepharose (Papermaster et al., 1978). It was rats using freeze-fracture, immunocytochemistry with anti-opsin, and biotinylated using N-hydroxysuccinimide ester, according to the procedure lectin cytochemistry. We chose neonatal rats for these studies of Heitzman and Richards (1974) and was detected by avidin-ferritin pre- because the entire process of ROS formation occurs postnatally pared by the method of Heitzman and Richards (1974) or obtained directly (Weidman and Kuwabara, 1969; Galbavy and Olson, 1979) and from Vector Laboratories (Burlingame, CA). because the small size and high density of photoreceptors in their To examine antibody specificity under conditions similar to those of our retinas enabled us to observe large numbers of cilia in sections. Our immunocytochemistry experiments we separated proteins of a crude prep- principal results are that the ciliary plasma membrane consists of aration of rat outer segments prepared as in the preceding paper (Defoe and distinct proximal and distal domains with unique structural properties Besharse, 1985) or whole retina on 8 to 18% polyacrylamide gradient gels and that those domains have different binding affinities for anti-opsin using essentially the method of Laemmli (1970). lmmunoreplicas were pre- and lectins. Even during the period prior to disc formation opsin is pared and stained using the procedures described in the preceding paper (Defoe and Besharse, 1985). The only protein staining specifically in any of concentrated in the distal region from which discs form. The results the immunoreplicas was opsin (37,000 daltons) and its dimer, trimer, and suggest that the unique proximal zone of the cilium plays a role in tetramer. The latter characteristically form in our discontinuous SDS-polyacryl- transport of opsin to the distal cilium, as well as the maintenance of amide system. distinct membrane domains. Controls for specific binding of anti-opsin in the immunocytochemistry experiments were carried out in each separate labeling experiment. These Materials and Methods involved use of biotinylated IgG of the preimmune serum at the same IgG Animals and fixation of retinas. Fisher strain rats were obtained at 3, 5, concentrations as those for specific IgG followed by avidin-ferritin, or treat- 6, 7, 9, 11, and 15 days of postnatal development; three additional experi- ment with avidin-ferritin without prior treatment with antibody. Ferritin grains ments were carried out on 3-day-old Sprague-Dawley rats. It is important to were rare on tissues treated by either procedure. After labeling with anti- point out that we studied photoreceptors
Recommended publications
  • G Protein-Coupled Receptors: What a Difference a ‘Partner’ Makes
    Int. J. Mol. Sci. 2014, 15, 1112-1142; doi:10.3390/ijms15011112 OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 www.mdpi.com/journal/ijms Review G Protein-Coupled Receptors: What a Difference a ‘Partner’ Makes Benoît T. Roux 1 and Graeme S. Cottrell 2,* 1 Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK; E-Mail: [email protected] 2 Reading School of Pharmacy, University of Reading, Reading RG6 6UB, UK * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +44-118-378-7027; Fax: +44-118-378-4703. Received: 4 December 2013; in revised form: 20 December 2013 / Accepted: 8 January 2014 / Published: 16 January 2014 Abstract: G protein-coupled receptors (GPCRs) are important cell signaling mediators, involved in essential physiological processes. GPCRs respond to a wide variety of ligands from light to large macromolecules, including hormones and small peptides. Unfortunately, mutations and dysregulation of GPCRs that induce a loss of function or alter expression can lead to disorders that are sometimes lethal. Therefore, the expression, trafficking, signaling and desensitization of GPCRs must be tightly regulated by different cellular systems to prevent disease. Although there is substantial knowledge regarding the mechanisms that regulate the desensitization and down-regulation of GPCRs, less is known about the mechanisms that regulate the trafficking and cell-surface expression of newly synthesized GPCRs. More recently, there is accumulating evidence that suggests certain GPCRs are able to interact with specific proteins that can completely change their fate and function. These interactions add on another level of regulation and flexibility between different tissue/cell-types.
    [Show full text]
  • Melanopsin: an Opsin in Melanophores, Brain, and Eye
    Proc. Natl. Acad. Sci. USA Vol. 95, pp. 340–345, January 1998 Neurobiology Melanopsin: An opsin in melanophores, brain, and eye IGNACIO PROVENCIO*, GUISEN JIANG*, WILLEM J. DE GRIP†,WILLIAM PA¨R HAYES‡, AND MARK D. ROLLAG*§ *Department of Anatomy and Cell Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814; †Institute of Cellular Signaling, University of Nijmegen, 6500 HB Nijmegen, The Netherlands; and ‡Department of Biology, The Catholic University of America, Washington, DC 20064 Edited by Jeremy Nathans, Johns Hopkins University School of Medicine, Baltimore, MD, and approved November 5, 1997 (received for review September 16, 1997) ABSTRACT We have identified an opsin, melanopsin, in supernatants subjected to SDSyPAGE analysis and subse- photosensitive dermal melanophores of Xenopus laevis. Its quent electroblotting onto a poly(vinylidene difluoride) mem- deduced amino acid sequence shares greatest homology with brane. The blot was probed with a 1:2,000 dilution of antisera cephalopod opsins. The predicted secondary structure of (CERN 886) raised against bovine rhodopsin and detected by melanopsin indicates the presence of a long cytoplasmic tail enhanced chemiluminescence. with multiple putative phosphorylation sites, suggesting that cDNA Library Screen. A X. laevis dermal melanophore this opsin’s function may be finely regulated. Melanopsin oligo(dT) cDNA library was screened with a mixture of mRNA is expressed in hypothalamic sites thought to contain 32P-labeled probes. Probes were synthesized by random prim- deep brain photoreceptors and in the iris, a structure known ing of TA-cloned (Invitrogen) fragments of X. laevis rhodopsin to be directly photosensitive in amphibians. Melanopsin mes- (7) (759 bp) and violet opsin (8) (279 bp) cDNAs.
    [Show full text]
  • The Vertebrate Ancestral Repertoire of Visual Opsins, Transducin Alpha Subunits and Oxytocin/Vasopressin Receptors Was Establish
    Lagman et al. BMC Evolutionary Biology 2013, 13:238 http://www.biomedcentral.com/1471-2148/13/238 RESEARCH ARTICLE Open Access The vertebrate ancestral repertoire of visual opsins, transducin alpha subunits and oxytocin/ vasopressin receptors was established by duplication of their shared genomic region in the two rounds of early vertebrate genome duplications David Lagman1†, Daniel Ocampo Daza1†, Jenny Widmark1,XesúsMAbalo1, Görel Sundström1,2 and Dan Larhammar1* Abstract Background: Vertebrate color vision is dependent on four major color opsin subtypes: RH2 (green opsin), SWS1 (ultraviolet opsin), SWS2 (blue opsin), and LWS (red opsin). Together with the dim-light receptor rhodopsin (RH1), these form the family of vertebrate visual opsins. Vertebrate genomes contain many multi-membered gene families that can largely be explained by the two rounds of whole genome duplication (WGD) in the vertebrate ancestor (2R) followed by a third round in the teleost ancestor (3R). Related chromosome regions resulting from WGD or block duplications are said to form a paralogon. We describe here a paralogon containing the genes for visual opsins, the G-protein alpha subunit families for transducin (GNAT) and adenylyl cyclase inhibition (GNAI), the oxytocin and vasopressin receptors (OT/VP-R), and the L-type voltage-gated calcium channels (CACNA1-L). Results: Sequence-based phylogenies and analyses of conserved synteny show that the above-mentioned gene families, and many neighboring gene families, expanded in the early vertebrate WGDs. This allows us to deduce the following evolutionary scenario: The vertebrate ancestor had a chromosome containing the genes for two visual opsins, one GNAT, one GNAI, two OT/VP-Rs and one CACNA1-L gene.
    [Show full text]
  • The Photopigment Melanopsin Is Exclusively Present in Pituitary
    The Journal of Neuroscience, 2002, Vol. 22 RC191 1of7 The Photopigment Melanopsin Is Exclusively Present in Pituitary Adenylate Cyclase-Activating Polypeptide-Containing Retinal Ganglion Cells of the Retinohypothalamic Tract Jens Hannibal, Peter Hindersson, Sanne M. Knudsen, Birgitte Georg, and Jan Fahrenkrug Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark Mammalian circadian rhythms generated in the hypothalamic strate that the distribution of melanopsin was identical to that of suprachiasmatic nuclei are entrained to the environmental light/ the PACAP-containing retinal ganglion cells. Colocalization dark cycle via a monosynaptic pathway, the retinohypothalamic studies using the specific melanopsin antibody and/or cRNA tract (RHT). We have shown previously that retinal ganglion probes in combination with PACAP immunostaining revealed cells containing pituitary adenylate cyclase-activating polypep- that melanopsin was found exclusively in the PACAP- tide (PACAP) constitute the RHT. Light activates the RHT via containing retinal ganglion cells located at the surface of so- unknown photoreceptors different from the classical photore- mata and dendrites. These data, in conjunction with published ceptors located in the outer retina. Two types of photopig- action spectra analyses and work in retinally degenerated (rd/ ments, melanopsin and the cryptochromes (CRY1 and CRY2), rd/cl) mutant mice, suggest that melanopsin is a circadian both of which are located in the inner retina, have been sug- photopigment located in retinal ganglion cells projecting to the gested as “circadian photopigments.” In the present study, we biological clock. cloned rat melanopsin photopigment cDNA and produced a specific melanopsin antibody. Using in situ hybridization histo- Key words: colocalization; suprachiasmatic nucleus; circa- chemistry combined with immunohistochemistry, we demon- dian rhythm; rat; immunohistochemistry; melanopsin antibodies Mammalian circadian rhythms of behavior and physiology are are unknown.
    [Show full text]
  • Color Vision Deficiency
    Color vision deficiency Description Color vision deficiency (sometimes called color blindness) represents a group of conditions that affect the perception of color. Red-green color vision defects are the most common form of color vision deficiency. Affected individuals have trouble distinguishing between some shades of red, yellow, and green. Blue-yellow color vision defects (also called tritan defects), which are rarer, cause problems with differentiating shades of blue and green and cause difficulty distinguishing dark blue from black. These two forms of color vision deficiency disrupt color perception but do not affect the sharpness of vision (visual acuity). A less common and more severe form of color vision deficiency called blue cone monochromacy causes very poor visual acuity and severely reduced color vision. Affected individuals have additional vision problems, which can include increased sensitivity to light (photophobia), involuntary back-and-forth eye movements (nystagmus) , and nearsightedness (myopia). Blue cone monochromacy is sometimes considered to be a form of achromatopsia, a disorder characterized by a partial or total lack of color vision with other vision problems. Frequency Red-green color vision defects are the most common form of color vision deficiency. This condition affects males much more often than females. Among populations with Northern European ancestry, it occurs in about 1 in 12 males and 1 in 200 females. Red- green color vision defects have a lower incidence in almost all other populations studied. Blue-yellow color vision defects affect males and females equally. This condition occurs in fewer than 1 in 10,000 people worldwide. Blue cone monochromacy is rarer than the other forms of color vision deficiency, affecting about 1 in 100,000 people worldwide.
    [Show full text]
  • G Protein-Coupled Receptors in the Hypothalamic Paraventricular and Supraoptic Nuclei – Serpentine Gateways to Neuroendocrine Homeostasis
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Frontiers in Neuroendocrinology 33 (2012) 45–66 Contents lists available at ScienceDirect Frontiers in Neuroendocrinology journal homepage: www.elsevier.com/locate/yfrne Review G protein-coupled receptors in the hypothalamic paraventricular and supraoptic nuclei – serpentine gateways to neuroendocrine homeostasis Georgina G.J. Hazell, Charles C. Hindmarch, George R. Pope, James A. Roper, Stafford L. Lightman, ⇑ David Murphy, Anne-Marie O’Carroll, Stephen J. Lolait Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Dorothy Hodgkin Building, School of Clinical Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK article info abstract Article history: G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in the mamma- Available online 23 July 2011 lian genome. They are activated by a multitude of different ligands that elicit rapid intracellular responses to regulate cell function. Unsurprisingly, a large proportion of therapeutic agents target these receptors. Keywords: The paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus are important G protein-coupled receptor mediators in homeostatic control. Many modulators of PVN/SON activity, including neurotransmitters Paraventricular nucleus and hormones act via GPCRs – in fact over 100 non-chemosensory GPCRs have been detected in either Supraoptic nucleus the PVN or SON. This review provides a comprehensive summary of the expression of GPCRs within Vasopressin the PVN/SON, including data from recent transcriptomic studies that potentially expand the repertoire Oxytocin Corticotropin-releasing factor of GPCRs that may have functional roles in these hypothalamic nuclei.
    [Show full text]
  • Development of the Pattern of Photoreceptors in the Chick Retina
    The Journal of Neuroscience, February 15, 1996, 16(4):1430-1439 Development of the Pattern of Photoreceptors in the Chick Retina Suzanne L. Bruhn and Constance L. Cepko Department of Genetics, Harvard Medical School, Boston, Massachusetts 02175 The various classes of photoreceptor cells found in vertebrate differences in the localization of RNA within the inner segment retinae are organized in specific patterns, which are important of cone photoreceptors, suggesting that morphological differ- for visual function. It is not known how these patterns are entiation preceded the expression of photopigment molecules. achieved during development. The chick retina provides an Marked differences in the distribution of rods and cones were excellent model system in which to investigate this issue, con- also found. Within the area centralis, a circular rod-free zone taining cone opsins red, green, blue, and violet, as well as the bisected by a narrow rod-sparse region along the nasal-tem- rod-specific opsin rhodopsin. In this study, whole-mount in situ poral axis was evident as soon as rhodopsin RNA could be hybridization has revealed striking differences among opsins in detected. Such specialized regions appear to be set aside soon both spatial and temporal aspects of expression. The long- after photoreceptor cells become postmitotic, as evidenced by wavelength cone opsins, red and green, were first detected in a spatially restricted pattern of visinin RNA observed at E7. The a small spot within the area centralis at embryonic day 14 (El 4). onset of particular opsins in restricted regions of the retina In contrast, the short-wavelength cone opsins, blue and violet, suggest an underlying pattern related to visual function in the were not detected until 2 d later and showed domains of chick.
    [Show full text]
  • Structure and Function in Rhodopsin: the Fate of Opsin Formed Upon The
    Proc. Natl. Acad. Sci. USA Vol. 92, pp. 249-253, January 1995 Biochemistry Structure and function in rhodopsin: The fate of opsin formed upon the decay of light-activated metarhodopsin II in vitro (opsin unfolding/folding/denaturation/11-is-retinal/chromophore/regeneration) TAKESHI SAKAMOTO* AND H. GOBIND KHORANA Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 Contributed by H. Gobind Khorana, September 8, 1994 ABSTRACT We report that the light-activated bovine parallels the rate of decay of the Meta II intermediate. Thus, the metarhodopsin II, upon decay, first forms opsin in the cor- opsin formed upon decay of this intermediate regains the con- rectly folded form. The latter binds ll1-is-retinal and regen- formation ofthe native ground-state opsin. However, while being erates the native rhodopsin chromophore. However, when the kept in the dark in DM, the opsin converts to one or more opsin formed upon metarhodopsin II decay is kept in 0.1% non-11-cis-retinal-binding forms in a time-dependent manner. dodecyl maltoside, it converts in a time-dependent manner to Upon subsequent addition of 11-cis-retinal, a slow regeneration a form(s) that does not bind ll-cis-retinal. On subsequent of the native rhodopsin chromophore is observed. Usually, three addition of ll-cis-retinal, slow reversal of the non-retinal- rate components are observed for this process: the first, a rapid binding forms to the correctly folded retinal-binding form has one (t1l2 = 15-60 sec) ascribed to the surviving correctly folded been demonstrated.
    [Show full text]
  • Theoretical Study of the Interaction of Agonists with the 5-HT2A Receptor
    Theoretical study of the interaction of agonists with the 5-HT2A receptor Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. nat) der Fakultät für Chemie und Pharmazie der Universität Regensburg vorgelegt von Maria Elena Silva aus Buccinasco Regensburg 2008 Die vorliegende Arbeit wurde in der Zeit von Oktober 2004 bis August 2008 an der Fakultät für Chemie und Pharmazie der Universität Regensburg in der Arbeitsgruppe von Prof. Dr. A. Buschauer unter der Leitung von Prof. Dr. S. Dove angefertigt Die Arbeit wurde angeleitet von: Prof. Dr. S. Dove Promotiongesucht eingereicht am: 28. Juli 2008 Promotionkolloquium am 26. August 2008 Prüfungsausschuß: Vorsitzender: Prof. Dr. A. Buschauer 1. Gutachter: Prof. Dr. S. Dove 2. Gutachter: Prof. Dr. S. Elz 3. Prüfer: Prof. Dr. H.-A. Wagenknecht I Contents 1 Introduction ......................................................................................................... 1 1.1 G protein coupled receptors .....................................................................................1 1.1.1 GPCR classification ............................................................................................2 1.1.2 Signal transduction mechanisms in GPCRs .......................................................4 1.2 Serotonin (5-hydroxytryptamine, 5-HT) ....................................................................7 1.2.1 Historical overview ..............................................................................................7 1.2.2 Biosynthesis and metabolism
    [Show full text]
  • The Vertebrate Ancestral Repertoire of Visual Opsins, Transducin Alpha Subunits and Oxytocin/ Vasopressin Receptors Was Establis
    Lagman et al. BMC Evolutionary Biology 2013, 13:238 http://www.biomedcentral.com/1471-2148/13/238 RESEARCH ARTICLE Open Access The vertebrate ancestral repertoire of visual opsins, transducin alpha subunits and oxytocin/ vasopressin receptors was established by duplication of their shared genomic region in the two rounds of early vertebrate genome duplications David Lagman1†, Daniel Ocampo Daza1†, Jenny Widmark1,XesúsMAbalo1, Görel Sundström1,2 and Dan Larhammar1* Abstract Background: Vertebrate color vision is dependent on four major color opsin subtypes: RH2 (green opsin), SWS1 (ultraviolet opsin), SWS2 (blue opsin), and LWS (red opsin). Together with the dim-light receptor rhodopsin (RH1), these form the family of vertebrate visual opsins. Vertebrate genomes contain many multi-membered gene families that can largely be explained by the two rounds of whole genome duplication (WGD) in the vertebrate ancestor (2R) followed by a third round in the teleost ancestor (3R). Related chromosome regions resulting from WGD or block duplications are said to form a paralogon. We describe here a paralogon containing the genes for visual opsins, the G-protein alpha subunit families for transducin (GNAT) and adenylyl cyclase inhibition (GNAI), the oxytocin and vasopressin receptors (OT/VP-R), and the L-type voltage-gated calcium channels (CACNA1-L). Results: Sequence-based phylogenies and analyses of conserved synteny show that the above-mentioned gene families, and many neighboring gene families, expanded in the early vertebrate WGDs. This allows us to deduce the following evolutionary scenario: The vertebrate ancestor had a chromosome containing the genes for two visual opsins, one GNAT, one GNAI, two OT/VP-Rs and one CACNA1-L gene.
    [Show full text]
  • Ligand-Dependent Conformations and Dynamics of the Serotonin 5-HT2A Receptor Determine Its Activation and Membrane-Driven Oligomerization Properties
    Ligand-Dependent Conformations and Dynamics of the Serotonin 5-HT2A Receptor Determine Its Activation and Membrane-Driven Oligomerization Properties Jufang Shan1, George Khelashvili1, Sayan Mondal1, Ernest L. Mehler1, Harel Weinstein1,2* 1 Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York, United States of America, 2 The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, New York, United States of America Abstract From computational simulations of a serotonin 2A receptor (5-HT2AR) model complexed with pharmacologically and structurally diverse ligands we identify different conformational states and dynamics adopted by the receptor bound to the full agonist 5-HT, the partial agonist LSD, and the inverse agonist Ketanserin. The results from the unbiased all-atom molecular dynamics (MD) simulations show that the three ligands affect differently the known GPCR activation elements including the toggle switch at W6.48, the changes in the ionic lock between E6.30 and R3.50 of the DRY motif in TM3, and the dynamics of the NPxxY motif in TM7. The computational results uncover a sequence of steps connecting these experimentally-identified elements of GPCR activation. The differences among the properties of the receptor molecule interacting with the ligands correlate with their distinct pharmacological properties. Combining these results with quantitative analysis of membrane deformation obtained with our new method (Mondal et al, Biophysical Journal 2011), we show that distinct conformational rearrangements produced by the three ligands also elicit different responses in the surrounding membrane. The differential reorganization of the receptor environment is reflected in (i)-the involvement of cholesterol in the activation of the 5-HT2AR, and (ii)-different extents and patterns of membrane deformations.
    [Show full text]
  • Evolution of Mammalian Opn5 As a Specialized UV-Absorbing Title Pigment by a Single Amino Acid Mutation
    Evolution of mammalian Opn5 as a specialized UV-absorbing Title pigment by a single amino acid mutation. Yamashita, Takahiro; Ono, Katsuhiko; Ohuchi, Hideyo; Yumoto, Akane; Gotoh, Hitoshi; Tomonari, Sayuri; Sakai, Author(s) Kazumi; Fujita, Hirofumi; Imamoto, Yasushi; Noji, Sumihare; Nakamura, Katsuki; Shichida, Yoshinori Citation The Journal of biological chemistry (2014), 289(7): 3991-4000 Issue Date 2014-02-14 URL http://hdl.handle.net/2433/203075 This research was originally published in [ The Journal of Biological Chemistry, 289, 3991-4000. doi: Right 10.1074/jbc.M113.514075 © the American Society for Biochemistry and Molecular Biology Type Journal Article Textversion author Kyoto University Molecular property and expression pattern of mammalian Opn5 Evolution of mammalian Opn5 as a specialized UV-absorbing pigment by a single amino acid mutation* Takahiro Yamashita1,6, Katsuhiko Ono2,6, Hideyo Ohuchi3,6, Akane Yumoto1, Hitoshi Gotoh2, Sayuri Tomonari4, Kazumi Sakai1, Hirofumi Fujita3, Yasushi Imamoto1, Sumihare Noji4, Katsuki Nakamura5, and Yoshinori Shichida1 1Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, 2Department of Biology, Kyoto Prefectural University of Medicine, Kyoto 603-8334, Japan, 3Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan, 4Department of Life Systems, Institute of Technology and Science, University of Tokushima Graduate School, Tokushima 770-8506, Japan, 5Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan. *Running title: Molecular property and expression pattern of mammalian Opn5 Correspondence should be addressed to Y.S. ([email protected]) 6These authors contributed equally to this work. Keywords: Rhodopsin; Photoreceptors; Signal transduction; G proteins; Molecular evolution; non- visual photoreception Background: Opn5 is considered to regulate non-visual photoreception in the retina and brain of animals.
    [Show full text]