Publications by authors named "I Paarmann"

Glycine receptors (GlyRs) mediate inhibitory neurotransmission in spinal cord and brainstem. They are clustered at inhibitory postsynapses via a tight interaction of their β subunits (GlyRβ) with the scaffolding protein gephyrin. In an attempt to isolate additional proteins interacting with GlyRβ, we performed pulldown experiments with rat brain extracts using a glutathione S-transferase fusion protein encompassing amino acids 378-455 of the large intracellular loop of GlyRβ as bait.

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Inhibitory glycine receptors (GlyRs) are composed of homologous α- (α1-4) and β-subunits. The β-subunits (GlyRβ) interact via their large cytosolic loops with the postsynaptic scaffolding protein gephyrin and are therefore considered essential for synaptic localization. In situ hybridization studies indicate a widespread distribution of GlyRβ transcripts throughout the mammalian central nervous system (CNS), whereas GlyRα mRNAs and proteins display more restricted expression patterns.

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Inhibitory glycine receptors (GlyRs) are densely packed in the postsynaptic membrane due to a high-affinity interaction of their β-subunits with the scaffolding protein gephyrin. Here, we used an affinity-based proteomic approach to identify the trafficking proteins Vacuolar Protein Sorting 35 (Vps35) and Neurobeachin (Nbea) as novel GlyR β-subunit (GlyRβ) interacting proteins in rat brain. Recombinant Vps35 and a central fragment of Nbea bound to the large intracellular loop of GlyRβ in glutathione-S-transferase pull-downs; in addition, Vps35 displayed binding to gephyrin.

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In the mammalian CNS, each neuron typically receives thousands of synaptic inputs from diverse classes of neurons. Synaptic transmission to the postsynaptic neuron relies on localized and transmitter-specific differentiation of the plasma membrane with postsynaptic receptor, scaffolding, and adhesion proteins accumulating in precise apposition to presynaptic sites of transmitter release. We identified protein interactions of the synaptic adhesion molecule neuroligin 2 that drive postsynaptic differentiation at inhibitory synapses.

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Effector molecules such as calmodulin modulate the interactions of membrane-associated guanylate kinase homologs (MAGUKs) and other scaffolding proteins of the membrane cytoskeleton by binding to the Src homology 3 (SH3) domain, the guanylate kinase (GK) domain, or the connecting HOOK region of MAGUKs. Using surface plasmon resonance, we studied the interaction of members of all four MAGUK subfamilies--synapse-associated protein 97 (SAP97), calcium/calmodulin-dependent serine protein kinase (CASK), membrane palmitoylated protein 2 (MPP2), and zona occludens (ZO) 1--and calmodulin to determine interaction affinities and localize the binding site. The SH3-GK domains of the proteins and derivatives thereof were expressed in E.

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