title: Rapid assembly of functional presynaptic boutons triggered by adhesive contacts.
abstract: CNS synapse assembly typically follows after stable contacts between "appropriate" axonal and dendritic membranes are made. We show that presynaptic boutons selectively form de novo following neuronal fiber adhesion to beads coated with poly-d-lysine (PDL), an artificial cationic polypeptide. As demonstrated by atomic force and live confocal microscopy, functional presynaptic boutons self-assemble as rapidly as 1 h after bead contact, and are found to contain a variety of proteins characteristic of presynaptic endings. Interestingly, presynaptic compartment assembly does not depend on the presence of a biological postsynaptic membrane surface. Rather, heparan sulfate proteoglycans, including syndecan-2, as well as others possibly adsorbed onto the bead matrix or expressed on the axon surface, are required for assembly to proceed by a mechanism dependent on the dynamic reorganization of F-actin. Our results indicate that certain (but not all) nonspecific cationic molecules like PDL, with presumably electrostatically mediated adhesive properties, can effectively bypass cognate and natural postsynaptic ligands to trigger presynaptic assembly in the absence of specific target recognition. In contrast, we find that postsynaptic compartment assembly depends on the prior presence of a mature presynaptic ending.
authors.affiliation: Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec H3A 2B4, Canada.
authors.forename: Anna Lisa
authors.initials: AL
authors.lastname: Lucido
authors.forename: Fernando
authors.initials: F
authors.lastname: Suarez Sanchez
authors.forename: Peter
authors.initials: P
authors.lastname: Thostrup
authors.forename: Adam V
authors.initials: AV
authors.lastname: Kwiatkowski
authors.forename: Sergio
authors.initials: S
authors.lastname: Leal-Ortiz
authors.forename: Gopakumar
authors.initials: G
authors.lastname: Gopalakrishnan
authors.forename: Dalinda
authors.initials: D
authors.lastname: Liazoghli
authors.forename: Wiam
authors.initials: W
authors.lastname: Belkaid
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Lennox
authors.forename: Peter
authors.initials: P
authors.lastname: Grutter
authors.forename: Craig C
authors.initials: CC
authors.lastname: Garner
authors.forename: David R
authors.initials: DR
authors.lastname: Colman
mesh_terms: D000818:Animals; D001369:Axons; D002448:Cell Adhesion; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology* / Q000196:embryology / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013572:Synaptic Vesicles / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D008565:Membrane Proteins