Orapim Tulyathan

In the nervous system, homophilic and heterophilic adhesion molecules participate to the induction and differentiation of presynaptic transmitter release sites. The complex organization of the neuronal synapse requires isolating and studying specific recognition events to decipher the order of events leading to a functional synapse. I am interested in the heterophilic interaction between postsynaptic neuroligin (Nlg) and presynaptic beta-neurexin (Nrx). Nlg had been shown to trigger presynaptic differentiation in a Nrx-containing axon even when presented on a non-neuronal cell or on beads coated with lipid bilayers. I am focusing on a new method to image and quantitate the interactions between Nrx and Nlg using a model fluid bilayer containing GPI-Nlg that mimics the post-synaptic cell membrane and confines the contact zone to a plane. This approach enables us to monitor simultaneously, at the ensemble and single molecule level, both the redistribution of these proteins and the cell adhesion during interaction between a Nrx-expressing cell and a flat supported GPI-Nlg bilayer. Distinct patterns of Nrx distribution are associated with cell-bilayer adhesion and with the different neuroligins incorporated in the lipid supported bilayer.

• Giardia lamblia Attachment Force Is Insensitive to Surface Treatments. W. R. Hansen, O. Tulyathan, S. C. Dawson, W. Z. Cande, and D. A. Fletcher. Eukaryotic Cell, April 2006, p. 781-783, Vol. 5, No. 4
• Miller EW, Tulyathan O, Isacoff EY, Chang CJ. Molecular imaging of hydrogen peroxide produced for cell signaling. Nat Chem Biol. 2007 May;3(5):263-7. Epub 2007 Apr 1.
• Szobota S, Gorostiza P, Del Bene F, Wyart C, Fortin DL, Kolstad KD, Tulyathan O, Volgraf M, Numano R, Aaron HL, Scott EK, Kramer RH, Flannery J, Baier H, Trauner D, Isacoff EY. Remote control of neuronal activity with a light-gated glutamate receptor. Neuron. 2007 May 24;54(4):535-45.