Gabriel H. Travis, M.D.

Laboratory Address:
100 Stein Plaza
UCLA School of Medicine
Los Angeles, CA 90095

Work Address:
Stein Eye Institute
UCLA School of Medicine
Los Angeles, CA 90095

Affiliations
Affiliations
Professor, Ophthalmology, Biological Chemistry
Member, Biochemistry, Biophysics & Structural Biology GPB Home Area, Molecular, Cellular & Integrative Physiology GPB Home Area
Research Interests

Visual perception begins with absorption of a photon by a light-sensitive opsin in photoreceptor cells of the retina.  Opsins are members of the G protein-coupled receptor (GCPR) superfamily.  The visual opsins contain an 11‑cis‑retinaldehyde (11cRAL) chromophore, which is isomerized to all‑trans‑retinaldehyde (atRAL) by photon absorption.  This bleaches the opsin pigment, rendering it insensitive to light.  Light sensitivity is restored through the energetically uphill conversion of atRAL back to 11cRAL.  Our laboratory studies the biochemical and photochemical processes that carry out this conversion.  The genes for several retinoid-processing proteins are affected in human inherited retinal and macular degenerations. We are working to understand the function of several visual-cycle proteins, and how loss of function causes blindness in people with disease-causing mutations in visual-cycle genes.  We are particularly interested in mechanisms that permit sustained vision under daylight conditions.  Our laboratory employs a broad range of approaches to address these questions.  Several exciting projects are currently available.  These projects are especially suitable for students or fellows with interest in biochemistry who wish to work on problems in vision science with relevance to human inherited blindness. 

Biography:

Gabriel Travis is a biochemist and molecular biologist who has been on the faculty at UCLA in Ophthalmology and Biological Chemistry since 2001.  Professor Travis earned his BS degree in chemistry at UCLA, and his MD at UCLA School of Medicine. After completing a residency in neurology, Professor Travis left clinical medicine and devote himself full-time to basic research. He did a postdoctoral fellowship at the UCLA with Professor Michael Grunstein, and a second postdoctoral fellowship at Scripps Research Institute with Professor J. Gregor Sutcliffe.  He then took his first faculty position in Neuroscience at UT Southwestern Medical Center in Dallas, where he remained until moving to UCLA.  Professor Travis currently directs a research group that studies retinoid metabolism in photoreceptor cells and the mechanisms of inherited blinding diseases. 

Publications

A selected list of publications:

Cook Jeremy D, Ng Sze Yin, Lloyd Marcia, Eddington Shannan, Sun Hui, Nathans Jeremy, Bok Dean, Radu Roxana A, Travis Gabriel H   Peropsin modulates transit of vitamin A from retina to retinal pigment epithelium The Journal of biological chemistry, 2017; 292(52): 21407-21416.
Kaylor Joanna J, Xu Tongzhou, Ingram Norianne T, Tsan Avian, Hakobyan Hayk, Fain Gordon L, Travis Gabriel H   Blue light regenerates functional visual pigments in mammals through a retinyl-phospholipid intermediate Nature communications, 2017; 8(1): 16.
Kaylor Joanna J, Radu Roxana A, Bischoff Nicholas, Makshanoff Jacob, Hu Jane, Lloyd Marcia, Eddington Shannan, Bianconi Tran, Bok Dean, Travis Gabriel H   Diacylglycerol O-acyltransferase type-1 synthesizes retinyl esters in the retina and retinal pigment epithelium PloS one, 2015; 10(5): e0125921.
Kaylor Joanna J, Cook Jeremy D, Makshanoff Jacob, Bischoff Nicholas, Yong Jennifer, Travis Gabriel H   Identification of the 11-cis-specific retinyl-ester synthase in retinal Müller cells as multifunctional O-acyltransferase (MFAT) Proceedings of the National Academy of Sciences of the United States of America, 2014; 111(20): 7302-7.
Sato Kota, Li Songhua, Gordon William C, He Jibao, Liou Gregory I, Hill James M, Travis Gabriel H, Bazan Nicolas G, Jin Minghao   Receptor interacting protein kinase-mediated necrosis contributes to cone and rod photoreceptor degeneration in the retina lacking interphotoreceptor retinoid-binding protein The Journal of neuroscience : the official journal of the Society for Neuroscience, 2013; 33(44): 17458-68.
Kaylor Joanna J, Yuan Quan, Cook Jeremy, Sarfare Shanta, Makshanoff Jacob, Miu Anh, Kim Anita, Kim Paul, Habib Samer, Roybal C Nathaniel, Xu Tongzhou, Nusinowitz Steven, Travis Gabriel H   Identification of DES1 as a vitamin A isomerase in Müller glial cells of the retina Nature chemical biology, 2013; 9(1): 30-6.
Mullins Robert F, Kuehn Markus H, Radu Roxana A, Enriquez G Stephanie, East Jade S, Schindler Emily I, Travis Gabriel H, Stone Edwin M   Autosomal recessive retinitis pigmentosa due to ABCA4 mutations: clinical, pathologic, and molecular characterization Investigative ophthalmology & visual science, 2012; 53(4): 1883-94.
Kawaguchi Riki, Yu Jiamei, Ter-Stepanian Mariam, Zhong Ming, Cheng Guo, Yuan Quan, Jin Minghao, Travis Gabriel H, Ong David, Sun Hui   Receptor-mediated cellular uptake mechanism that couples to intracellular storage ACS chemical biology, 2011; 6(10): 1041-51.
Blakeley Lorie R, Chen Chunhe, Chen Ching-Kang, Chen Jeannie, Crouch Rosalie K, Travis Gabriel H, Koutalos Yiannis   Rod outer segment retinol formation is independent of Abca4, arrestin, rhodopsin kinase, and rhodopsin palmitylation Investigative ophthalmology & visual science, 2011; 52(6): 3483-91.
Radu Roxana A, Hu Jane, Yuan Quan, Welch Darcy L, Makshanoff Jacob, Lloyd Marcia, McMullen Stephen, Travis Gabriel H, Bok Dean   Complement system dysregulation and inflammation in the retinal pigment epithelium of a mouse model for Stargardt macular degeneration The Journal of biological chemistry, 2011; 286(21): 18593-601.
Liao Jo-Ling, Yu Juehua, Huang Kevin, Hu Jane, Diemer Tanja, Ma Zhicheng, Dvash Tamar, Yang Xian-Jie, Travis Gabriel H, Williams David S, Bok Dean, Fan Guoping   Molecular signature of primary retinal pigment epithelium and stem-cell-derived RPE cells Human molecular genetics, 2010; 19(21): 4229-38.
Linton Jonathan D, Holzhausen Lars C, Babai Norbert, Song Hongman, Miyagishima Kiyoharu J, Stearns George W, Lindsay Ken, Wei Junhua, Chertov Andrei O, Peters Theo A, Caffe Romeo, Pluk Helma, Seeliger Mathias W, Tanimoto Naoyuki, Fong Kimberly, Bolton Laura, Kuok Denise L T, Sweet Ian R, Bartoletti Theodore M, Radu Roxana A, Travis Gabriel H, Zagotta Willam N, Townes-Anderson Ellen, Parker Ed, Van der Zee Catharina E E M, Sampath Alapakkam P, Sokolov Maxim, Thoreson Wallace B, Hurley James B   Flow of energy in the outer retina in darkness and in light Proceedings of the National Academy of Sciences of the United States of America, 2010; 107(19): 8599-604.
Travis Gabriel H, Kaylor Joanna, Yuan Quan   Analysis of the retinoid isomerase activities in the retinal pigment epithelium and retina Methods in molecular biology (Clifton, N.J.), 2010; 652(2): 329-39.
Yuan Quan, Kaylor Joanna J, Miu Anh, Bassilian Sara, Whitelegge Julian P, Travis Gabriel H   Rpe65 isomerase associates with membranes through an electrostatic interaction with acidic phospholipid headgroups The Journal of biological chemistry, 2010; 285(2): 988-99.
Philp A R, Jin M, Li S, Schindler E I, Iannaccone A, Lam B L, Weleber R G, Fishman G A, Jacobson S G, Mullins R F, Travis Gabriel H, Stone Edwin M   Predicting the pathogenicity of RPE65 mutations Human mutation, 2009; 30(8): 1183-8.
Jin Minghao, Li Songhua, Nusinowitz Steven, Lloyd Marcia, Hu Jane, Radu Roxana A, Bok Dean, Travis Gabriel H   The role of interphotoreceptor retinoid-binding protein on the translocation of visual retinoids and function of cone photoreceptors The Journal of neuroscience : the official journal of the Society for Neuroscience, 2009; 29(5): 1486-95.
Radu Roxana A, Yuan Quan, Hu Jane, Peng Jennifer H, Lloyd Marcia, Nusinowitz Steven, Bok Dean, Travis Gabriel H   Accelerated accumulation of lipofuscin pigments in the RPE of a mouse model for ABCA4-mediated retinal dystrophies following Vitamin A supplementation Investigative ophthalmology & visual science, 2008; 49(9): 3821-9.
Radu Roxana A, Hu Jane, Peng Jennifer, Bok Dean, Mata Nathan L, Travis Gabriel H   Retinal pigment epithelium-retinal G protein receptor-opsin mediates light-dependent translocation of all-trans-retinyl esters for synthesis of visual chromophore in retinal pigment epithelial cells The Journal of biological chemistry, 2008; 283(28): 19730-8.
Brill Elliott, Malanson Katherine M, Radu Roxana A, Boukharov Natalia V, Wang Zhongyan, Chung Hae-Yun, Lloyd Marcia B, Bok Dean, Travis Gabriel H, Obin Martin, Lem Janis   A novel form of transducin-dependent retinal degeneration: accelerated retinal degeneration in the absence of rod transducin Investigative ophthalmology & visual science, 2007; 48(12): 5445-53.
Travis Gabriel H, Golczak Marcin, Moise Alexander R, Palczewski Krzysztof   Diseases caused by defects in the visual cycle: retinoids as potential therapeutic agents Annual review of pharmacology and toxicology, 2007; 47(29): 469-512.
Jin Minghao, Yuan Quan, Li Songhua, Travis Gabriel H   Role of LRAT on the retinoid isomerase activity and membrane association of Rpe65 The Journal of biological chemistry, 2007; 282(29): 20915-24.
Bui Tam V, Han Yun, Radu Roxana A, Travis Gabriel H, Mata Nathan L   Characterization of native retinal fluorophores involved in biosynthesis of A2E and lipofuscin-associated retinopathies The Journal of biological chemistry, 2006; 281(26): 18112-9.
Kaschula Catherine H, Jin Ming-Hao, Desmond-Smith Nicholas S, Travis Gabriel H   Acyl CoA:retinol acyltransferase (ARAT) activity is present in bovine retinal pigment epithelium Experimental eye research, 2006; 82(1): 111-21.
Radu Roxana A, Han Yun, Bui Tam V, Nusinowitz Steven, Bok Dean, Lichter Jay, Widder Ken, Travis Gabriel H, Mata Nathan L   Reductions in serum vitamin A arrest accumulation of toxic retinal fluorophores: a potential therapy for treatment of lipofuscin-based retinal diseases Investigative ophthalmology & visual science, 2005; 46(12): 4393-401.
Mata Nathan L, Ruiz Alberto, Radu Roxana A, Bui Tam V, Travis Gabriel H   Chicken retinas contain a retinoid isomerase activity that catalyzes the direct conversion of all-trans-retinol to 11-cis-retinol Biochemistry, 2005; 44(35): 11715-21.
Jin Minghao, Li Songhua, Moghrabi Walid N, Sun Hui, Travis Gabriel H   Rpe65 is the retinoid isomerase in bovine retinal pigment epithelium Cell, 2005; 122(3): 449-59.
Travis Gabriel H   DISCO! Dissociation of cone opsins: the fast and noisy life of cones explained Neuron, 2005; 46(6): 840-2.
Radu Roxana A, Mata Nathan L, Bagla Aarti, Travis Gabriel H   Light exposure stimulates formation of A2E oxiranes in a mouse model of Stargardt's macular degeneration Proceedings of the National Academy of Sciences of the United States of America, 2004; 101(16): 5928-33.
Radu Roxana A, Mata Nathan L, Nusinowitz Steven, Liu Xinran, Travis Gabriel H   Isotretinoin treatment inhibits lipofuscin accumulation in a mouse model of recessive Stargardt's macular degeneration Novartis Foundation symposium, 2004; 255(1): 51-63; discussion 63-7, 177-8.
Mata Nathan L, Moghrabi Walid N, Lee Jung S, Bui Tam V, Radu Roxana A, Horwitz Joseph, Travis Gabriel H   Rpe65 is a retinyl ester binding protein that presents insoluble substrate to the isomerase in retinal pigment epithelial cells The Journal of biological chemistry, 2004; 279(1): 635-43.
Radu Roxana A, Mata Nathan L, Nusinowitz Steven, Liu Xinran, Sieving Paul A, Travis Gabriel H   Treatment with isotretinoin inhibits lipofuscin accumulation in a mouse model of recessive Stargardt's macular degeneration Proceedings of the National Academy of Sciences of the United States of America, 2003; 100(8): 4742-7.
Mata Nathan L, Radu Roxana A, Clemmons Richard C, Travis Gabriel H   Isomerization and oxidation of vitamin a in cone-dominant retinas: a novel pathway for visual-pigment regeneration in daylight Neuron, 2002; 36(1): 69-80.