Wangsun Choi Alumni Page

Background & Contact Information

Current Position:  Instructor, Harvard Medical School and Associate Scientist, Turner Lab, Brigham and Women’s Hospital

Postdoctoral Fellow (2009 – 2016)
Education: University of Kentucky, Lexington, Kentucky
Ph.D., Biochemistry 2008 (Advisor: Dr. Sidney W. Whiteheart)
Korea University, Seoul, South Korea
M.S., Life Science and Biotechnology, 1999 (Advisor: Dr. Kwangseog Ahn)
B.A., Genetic Engineering, 1997
Fellowships & Awards: American Heart Association (AHA) Predoctoral Fellowship, 2006 – 2008
Title of Project: The Role of ADP-ribosylation factor 6 (Arf6) in Platelet Activation


Research Information
Exploring the roles of Canoe/Afadin and Pyd/ZO-1 in adhesion and cytoskeletal regulationCells undergo coordinated changes in shape and position during animal development. This process of morphogenesis requires cells to be able to interact with other cells and the extracellular matrix, and to be able to modulate both adhesion and the connections of cell-cell and cell-matrix junctions with the actin cytoskeleton. Adherens junctions (AJs) are the major sites of cell-cell contact in epithelial cells and this multi-protein complex also links the cytoskeleton of adjacent cells. While the key components of AJs are known, there are other proteins that are recruited to AJs whose functions are less well understood. These presumed non-core AJ proteins may act redundantly to modulate junctions by regulating connections to the actin cytoskeleton or to signal transduction machinery.Two presumed non-core AJ proteins are Canoe (Cno/AF-6) and Polycheatoid (Pyd/ZO-1). Studies of the mammalian homolog of Cno, AF-6, suggest that it plays a key role in AJs. The primary function of mammalian ZO-1 is in the tight junctions, but there is some evidence that it plays a transient role in the AJs. Both Cno and Pyd localize to the AJs in flies and have been found to genetically and physically interact. However, the role(s) of Cno and Pyd in AJs remains unclear. We generated null alleles of the single Drosophila ZO protein Polychaetoid (Pyd). Most embryos lacking Pyd die with striking defects in morphogenesis of embryonic epithelia including the epidermis, segmental grooves and tracheal system. Pyd loss does not dramatically affect AJ protein localization, or initial localization of actin and myosin during dorsal closure. However, Pyd loss does affect several cell behaviors that drive dorsal closure. The defects, which include segmental grooves that fail to retract, a disrupted leading-edge actin cable, and reduced zippering as leading edges meet, closely resemble defects in canoe zygotic null mutants, and in embryos lacking the actin regulator Enabled, suggesting these proteins act together. Canoe and Pyd are required for proper Enabled localization during dorsal closure, and strong genetic interactions suggest that Canoe, Pyd and Ena act together in regulating or anchoring the actin cytoskeleton during dorsal closure.


  • Bonello, T.T., Choi, W., and Peifer, M.  (2019).  Scribble and Discs-large direct initial assembly and positioning of adherens junctions during establishment of apical-basal polarity.  Development 146,  pii: dev180976.
  • Choi, W., Acharya, B.R., Peyret, G., Fardin, M-A. Mège, R-M., Ladoux, B., Yap, A.S., Fanning, A.S., Peifer, M. (2016). Remodeling the zonula adherens in response to tension and the role of afadin in this response. Journal of Cell Biology 213, 243-60.
  • Choi, W., Harris, N. J., Sumigray, K.D., and Peifer, M.  (2013).  Rap1 and Canoe/afadin are essential for establishment of apical-basal polarity in the Drosophila embryo.  Molecular Biology of the Cell 24, 945-963.
  • Choi W, Peifer M. Cell biology. Arranging a cellular checkerboard. Science. 2011;333(6046):1099-100.
  • Sawyer JK, Choi W, Jung KC, He L, Harris NJ, Peifer M. A contractile actomyosin network linked to adherens junctions by Canoe/afadin helps drive convergent extension. Mol Biol Cell. 2011;22(14):2491-508.
  • Choi W, Jung KC, Nelson KS, Bhat MA, Beitel GJ, Peifer M, Fanning AS. The single Drosophila ZO-1 protein Polychaetoid regulates embryonic morphogenesis in coordination with Canoe/Afadin and Enabled. Mol Biol Cell. 2011;22(12):2010-30.
  • Choi W., Karim Z. A., Whiteheart S. W. Protein Expression in Platelets from Six Species that Differ in their Open Canalicular System. Platelets. 2010;21(3):167-75.
  • Karim Z.A., Choi W., Whiteheart S.W. Primary platelet signaling cascades and integrin-mediated signaling control ADP-ribosylation factor (Arf) 6-GTP levels during platelet activation and aggregation. J. Biol. Chem. 2008;283(18):11995-2003.
  • Ren Q., Barber H.K., Crawford G.L., Karim Z.A., Zhao C., Choi W., Wang C.C., Hong W., Whiteheart S.W. Endobrevin/VAMP-8 is the primary v-SNARE for the platelet release reaction. Mol. Biol. Cell. 2007;18(1):24-33.
  • Choi W., Karim Z.A., Whiteheart S.W. Arf6 plays an early role in platelet activation by collagen and convulxin. Blood. 2006;107(8):3145-3152
  • Schraw T.D., Crawford G.L., Ren Q., Choi W., Thurmond D.C., Pessin J., Whiteheart S.W. Platelets from Munc18c heterozygous mice exhibit normal stimulus-induced release. Thromb. Haemost. 2004;92(4):829-37.
  • Choi W., Eum S.Y., Lee Y.W., Hennig B., Robertson L.W., Toborek M. PCB 104-induced proinflammatory reactions in human vascular endothelial cells: relationship to cancer metastasis and atherogenesis. Toxicol. Sci. 2003;75(1):47-56.


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