Neuronal synapse interaction reconstituted between live cells and supported lipid bilayers.
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.
Pautot
Sophie
S
Materials Sciences and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Lee
Hanson
H
Isacoff
Ehud Y
EY
Groves
Jay T
JT
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*
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