title: Neuronal synapse interaction reconstituted between live cells and supported lipid bilayers.
abstract: In the nervous system, homophilic and heterophilic adhesion molecules participate in the induction and differentiation of presynaptic transmitter release sites. We focus on the heterophilic interaction between postsynaptic neuroligin-1 (Nlg) and presynaptic beta-neurexin (Nrx). Nlg has previously been shown to trigger presynaptic differentiation in a Nrx-expressing axon even when presented on a non-neuronal cell or on beads coated with lipid bilayers. We have now developed a new method to measure single molecule and ensemble distribution of Nrx and Nlg at the contact site between a non-neuronal Nrx-expressing cell and a flat supported glycosylphosphoinositol-neuroligin-1 (GPI-Nlg) lipid bilayer and relate them to adhesion as measured by cell migration and gravity dissociation. We find that within minutes after cell-bilayer contact, Nrx accumulates at the contact site and the contact area is expanded. The strength of cell-bilayer adhesion depends on the morphology of Nrx accumulation, with the focal concentration strengthening adhesion. The results suggest that Nlg-Nrx interaction rapidly establishes a weak, but specific, adhesion between dynamic pre- and postsynaptic processes, which may ultimately require additional molecules for synapse stabilization.
authors.affiliation: Materials Sciences and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Sophie
authors.initials: S
authors.lastname: Pautot
authors.forename: Hanson
authors.initials: H
authors.lastname: Lee
authors.forename: Ehud Y
authors.initials: EY
authors.lastname: Isacoff
authors.forename: Jay T
authors.initials: JT
authors.lastname: Groves
mesh_terms: D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008567:Membranes, Artificial; D051379:Mice; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D011485:Protein Binding / Q000502:physiology; D013569:Synapses / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D017261:Glycosylphosphatidylinositols; D008051:Lipid Bilayers; D008565:Membrane Proteins; D008567:Membranes, Artificial; D009419:Nerve Tissue Proteins; C093438:neuroligin 1; C086959:neurexin Ibeta