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Hui Sun, Ph.D.

Email Address:
hsun@mednet.ucla.edu

Laboratory Address:
Laboratory
CHS 53-140

UNITED STATES

Work Address:
Office
CHS 53-140A

UNITED STATES

Lab Number:
310-206-4018
Office Phone Number:
206-4017
310-206-4017



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Department / Division Affiliations
Associate Professor, Physiology
Member, ACCESS Program: Dept. of Molecular, Cell & Integrative Physiology, Access Biochemistry, Biophysics, Structural Biology Home Area, Access Molecular, Cellular and Integrative Physiology Home Area, Brain Research Institute
Faculty, Molecular, Cellular, and Integrative Physiology IDP

Research Interest:

Physiological and pathological mechanisms in vision

Mechanism of vitamin A transport: Vitamin A has diverse biological functions. Vitamin A derivatives (retinoids) serve as the chromophore for photoreceptor proteins in vision and exert profound effects on cell growth and differentiation in embryonic development and adult organ systems by interacting with their nuclear hormone receptors. Vitamin A is transported in the blood by a carrier protein called retinol binding protein (RBP). Using a new biochemical strategy followed by mass spectrometry, we identified the long-sought membrane receptor for RBP. The RBP receptor is a multitransmembrane domain protein of previously unknown function. We found that the RBP receptor binds to RBP with high affinity and has robust vitamin A uptake activity. Consistent with the diverse functions of vitamin A, the RBP receptor is expressed in diverse organ systems, such as the nervous system, the reproductive systems, the immune system, the respiratory system, and the skin, all of which are known to depend on vitamin A for proper function. We are using several strategies to study this new membrane transport system.

Publications:

Kawaguchi, R., Yu, J., Honda, J., Hu, J., Whitelegge, J., Ping, P., Wiita, P., Bok, D., and Sun, H. A membrane receptor for retinol binding protein mediates cellular uptake of vitamin A. Science 2007; 315: 820-825.
Yang, Z., Camp, N., Sun, H., Tong, Z., Gibbs, D., Cameron, J., Chen, H., Zhao, Y., Pearson, E., Li, X., Chien, J., DeWan, A., Harmon, J., Bernstein, P., Shridhar, V., Zabriskie, N., Hoh, J., Howes, K., and Zhang, K. A variant of the HTRA1 gene increases susceptibility to age-related macular degeneration. Science 2006; 314: 992-993.
Jin, M., Li, S., Moghrabi, W.N., Sun, H., and Travis, G.H. RPE65 is the retinoid isomerase in bovine retinal pigment epithelium. Cell 2005; 122: 449-459.
Sun, H Tsunenari, T Yau, KW Nathans, J The vitelliform macular dystrophy protein defines a new family of chloride channels. Proc. Natl. Acad. Sci. USA 2002; 99(6): 4008-13.
Sun, H Nathans, J Mechanistic studies of ABCR, the ABC transporter in photoreceptor outer segments responsible for autosomal recessive Stargardt disease. J Bioenerg Biomembr 2001; 33(6): 523-30.
Sun, H Nathans, J ABCR, the ATP-binding cassette transporter responsible for Stargardt macular dystrophy, is an efficient target of all-trans-retinal-mediated photooxidative damage in vitro. Implications for retinal disease. The Journal of Biological Chemistry. 2001; 276(15): 11766-74.
Sun, H Smallwood, PM Nathans, J Biochemical defects in ABCR protein variants associated with human retinopathies. Nature Genetics. 2000; 26(2): 242-6.
Sun, H Nathans, J ABCR: rod photoreceptor-specific ABC transporter responsible for Stargardt disease. Methods in enzymology. 2000; 315: 879-97.
Sun, H Molday, RS Nathans, J Retinal stimulates ATP hydrolysis by purified and reconstituted ABCR, the photoreceptor-specific ATP-binding cassette transporter responsible for Stargardt disease. The Journal of Biological Chemistry. 1999; 274(12): 8269-81.
Sun, H Nathans, J Stargardt's ABCR is localized to the disc membrane of retinal rod outer segments. Nature Genetics. 1997; 17(1): 15-6.
Sun, H Macke, JP Nathans, J Mechanisms of spectral tuning in the mouse green cone pigment. Proc. Natl. Acad. Sci. USA 1997; 94(16): 8860-5.
Allikmets, R Singh, N Sun, H Shroyer, NF Hutchinson, A Chidambaram, A Gerrard, B Baird, L Stauffer, D Peiffer, A Rattner, A Smallwood, P Li, Y Anderson, KL Lewis, RA Nathans, J Leppert, M Dean, M Lupski, JR A photoreceptor cell-specific ATP-binding transporter gene (ABCR) is mutated in recessive Stargardt macular dystrophy. Nature Genetics. 1997; 15(3): 236-46.
Sun, H., and Kawaguchi, R. The Membrane Receptor for Plasma Retinol Binding Protein, a New Type of Cell-Surface Receptor. Int Rev Cell Mol Biol. 2011; 288(1-41): .
Kawaguchi, R., Yu, J., Ter-Stepanian, M., Zhong, M., Guo, C., Yuan, Q., Jin, M., Travis, G.H., Ong, D., and Sun, H. Receptor-Mediated Cellular Uptake Mechanism that is Coupled to Intracellular Storage. ACS Chemical Biology 2011; 6: 1041-51.