Hui Sun

Professor, Physiology, University of California Los Angeles

Professor, Ophthalmology, University of California Los Angeles

Dr. Sun's lab has focused on the discovery, mechanistic study and identifying small molecule modulators of novel membrane receptors that play important roles in physiology and diseases. To achieve these goals, several new techniques have been developed by his lab. The first major discovery is the membrane receptor that mediates cellular uptake of vitamin A, a chemical essential for human survival. This receptor is expressed in blood-organ barriers and eluded identification for more than 30 years. Another discovery is the signaling receptor for the most potent endogenous inhibitor of angiogenesis. This receptor is highly specifically expressed in pathogenic blood vessels including tumor blood vessels. By developing a novel fluorescence-based technique, his team and collaborators identified potent chemical compounds that target this receptor to specifically kill tumor blood vessels to lead to effective tumor killing in vivo. In the past few years, his lab also developed a novel technique to screen for receptor-activating antibodies and successfully identified antibody drug candidates of this receptor after large-scale screening 10 billion human antibody clones in collaboration with scientists within and outside of UCLA.

Awards and Honors

  • E. Matilda Ziegler Foundation Award, E. Matilda Ziegler Foundation, 2005-2008.
  • Alicia Showalter Reynolds Research Prize, Johns Hopkins University, 1998.
  • Ellison Medical Foundation New Scholar Award, Ellison Medical Foundation, 2006-2010.
  • Gerald Oppenheimer Family Foundation Award, UCLA, 2005.
  • Howard Hughes Medical Institute Early Career Scientist Award, Howard Hughes Medical Institute, 2009-2015.
  • Karl Kirchgessner Foundation Award, Karl Kirchgessner Foundation, 2003.
  • Ruth and Milton Steinbach Award, Ruth and Milton Steinbach Foundation, 2004-2007.
  • Stein-Oppenheimer Endowment Award, UCLA, 2004.


  1. Zhong M, Kawaguchi R, Costabile B, Tang Y, Hu J, Cheng G, Kassai M, Ribalet B, Mancia F, Bok D, Sun H. Regulatory mechanism for the transmembrane receptor that mediates bidirectional vitamin A transport.. Proceedings of the National Academy of Sciences of the United States of America, 2020.
  2. Cook JD, Ng SY, Lloyd M, Eddington S, Sun H, Nathans J, Bok D, Radu RA, Travis GH. Peropsin modulates transit of vitamin A from retina to retinal pigment epithelium.. The Journal of biological chemistry, 2017.
  3. Kawaguchi R, Zhong M, Kassai M, Ter-Stepanian M, Sun H. Vitamin A Transport Mechanism of the Multitransmembrane Cell-Surface Receptor STRA6.. Membranes, 2015.
  4. Zhong M, Sun H. A genetic clog in the vitamin A transport machinery.. Cell, 2015.
  5. Cheng G, Zhong M, Kawaguchi R, Kassai M, Al-Ubaidi M, Deng J, Ter-Stepanian M, Sun H. Identification of PLXDC1 and PLXDC2 as the transmembrane receptors for the multifunctional factor PEDF.. eLife, 2014.
  6. Kawaguchi R, Zhong M, Sun H. Real-time analyses of retinol transport by the membrane receptor of plasma retinol binding protein.. Journal of visualized experiments : JoVE, 2013.
  7. Kawaguchi R, Zhong M, Kassai M, Ter-Stepanian M, Sun H. STRA6-catalyzed vitamin A influx, efflux, and exchange.. The Journal of membrane biology, 2012.
  8. Kawaguchi R, Yu J, Ter-Stepanian M, Zhong M, Cheng G, Yuan Q, Jin M, Travis GH, Ong D, Sun H. Receptor-mediated cellular uptake mechanism that couples to intracellular storage.. ACS chemical biology, 2011.
  9. Kawaguchi R, Sun H. Techniques to study specific cell-surface receptor-mediated cellular vitamin A uptake.. Methods in molecular biology (Clifton, N.J.), 2010.
  10. Kawaguchi R, Yu J, Wiita P, Honda J, Sun H. An essential ligand-binding domain in the membrane receptor for retinol-binding protein revealed by large-scale mutagenesis and a human polymorphism.. The Journal of biological chemistry, 2008.
  11. Yu J, Wiita P, Kawaguchi R, Honda J, Jorgensen A, Zhang K, Fischetti VA, Sun H. Biochemical analysis of a common human polymorphism associated with age-related macular degeneration.. Biochemistry, 2007.
  12. Kawaguchi R, Yu J, Honda J, Hu J, Whitelegge J, Ping P, Wiita P, Bok D, Sun H. A membrane receptor for retinol binding protein mediates cellular uptake of vitamin A.. Science (New York, N.Y.), 2007.
  13. Yang Z, Camp NJ, Sun H, Tong Z, Gibbs D, Cameron DJ, Chen H, Zhao Y, Pearson E, Li X, Chien J, Dewan A, Harmon J, Bernstein PS, Shridhar V, Zabriskie NA, Hoh J, Howes K, Zhang K. A variant of the HTRA1 gene increases susceptibility to age-related macular degeneration.. Science (New York, N.Y.), 2006.
  14. Jin M, Li S, Moghrabi WN, Sun H, Travis GH. Rpe65 is the retinoid isomerase in bovine retinal pigment epithelium.. Cell, 2005.
  15. Tsunenari T, Sun H, Williams J, Cahill H, Smallwood P, Yau KW, Nathans J. Structure-function analysis of the bestrophin family of anion channels.. The Journal of biological chemistry, 2003.
  16. Sun H, Tsunenari T, Yau KW, Nathans J. The vitelliform macular dystrophy protein defines a new family of chloride channels.. Proceedings of the National Academy of Sciences of the United States of America, 2002.
  17. Sun H, Nathans J. The challenge of macular degeneration.. Scientific American, 2001.
  18. Sun H, Smallwood PM, Nathans J. Biochemical defects in ABCR protein variants associated with human retinopathies.. Nature genetics, 2000.
  19. 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.
  20. Chen S, Wang QL, Nie Z, Sun H, Lennon G, Copeland NG, Gilbert DJ, Jenkins NA, Zack DJ. Crx, a novel Otx-like paired-homeodomain protein, binds to and transactivates photoreceptor cell-specific genes.. Neuron, 1997.
  21. Sun H, Macke JP, Nathans J. Mechanisms of spectral tuning in the mouse green cone pigment.. Proceedings of the National Academy of Sciences of the United States of America, 1997.
  22. 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.