title: Intracellular Ca²⁺ and not the extracellular matrix determines surface dynamics of AMPA-type glutamate receptors on aspiny neurons.
abstract: The perisynaptic extracellular matrix (ECM) contributes to the control of the lateral mobility of AMPA-type glutamate receptors (AMPARs) at spine synapses of principal hippocampal neurons. Here, we have studied the effect of the ECM on the lateral mobility of AMPARs at shaft synapses of aspiny interneurons. Single particle tracking experiments revealed that the removal of the hyaluronan-based ECM with hyaluronidase does not affect lateral receptor mobility on the timescale of seconds. Similarly, cross-linking with specific antibodies against the extracellular domain of the GluA1 receptor subunit, which affects lateral receptor mobility on spiny neurons, does not influence receptor mobility on aspiny neurons. AMPARs on aspiny interneurons are characterized by strong inward rectification indicating a significant fraction of Ca(2+)-permeable receptors. Therefore, we tested whether Ca(2+) controls AMPAR mobility in these neurons. Application of the membrane-permeable Ca(2+) chelator BAPTA-AM significantly increased the lateral mobility of GluA1-containing synaptic and extrasynaptic receptors. These data indicate that the perisynaptic ECM affects the lateral mobility differently on spiny and aspiny neurons. Although ECM structures on interneurons appear much more prominent, their influence on AMPAR mobility seems to be negligible at short timescales.
authors.affiliation: Research group, Molecular Physiology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany Research group, Presynaptic Plasticity, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Klueva
authors.affiliation: Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany Center for Behavioral Brain Science (CBBS), Magdeburg, Germany Molecular Neurobiology, Medical Faculty, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Eckart D
authors.initials: ED
authors.lastname: Gundelfinger
authors.affiliation: Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany Renato.Frischknecht@lin-magdeburg.de.
authors.forename: R Renato
authors.initials: RR
authors.lastname: Frischknecht
authors.affiliation: Research group, Molecular Physiology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany Martin.Heine@lin-magdeburg.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Heine
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives; D004622:Embryo, Mammalian / Q000166:cytology; D005109:Extracellular Matrix / Q000378:metabolism*; D036681:Fluorescence Recovery After Photobleaching; D006624:Hippocampus / Q000166:cytology*; D009474:Neurons / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism*
chemical_list: D002118:Calcium; D004533:Egtazic Acid; D018091:Receptors, AMPA; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
keywords: extracellular matrix; glutamate receptor; interneurons; single particle tracking