Pin1-dependent signalling negatively affects GABAergic transmission by modulating neuroligin2/gephyrin interaction

Abstract

The cell adhesion molecule Neuroligin2 (NL2) is localized selectively at GABAergic synapses, where it interacts with the scaffolding protein gephyrin in the post-synaptic density. However, the role of this interaction for formation and plasticity of GABAergic synapses is unclear. Here, we demonstrate that endogenous NL2 undergoes proline-directed phosphorylation at its unique S714-P consensus site, leading to the recruitment of the peptidyl-prolyl cis–trans isomerase Pin1. This signalling cascade negatively regulates NL2’s ability to interact with gephyrin at GABAergic post-synaptic sites. As a consequence, enhanced accumulation of NL2, gephyrin and GABAA receptors was detected at GABAergic synapses in the hippocampus of Pin1-knockout mice (Pin1−/−) associated with an increase in amplitude of spontaneous GABAA-mediated post-synaptic currents. Our results suggest that Pin1-dependent signalling represents a mechanism to modulate GABAergic transmission by regulating NL2/gephyrin interaction.

Gephyrin: a central GABAergic synapse organizer

“…In addition, the absence of Pin1 was found to promote the formation of NL-2/gephyrin complexes, enrich GABA A receptors at inhibitory synaptic sites and inhibit synaptic transmission. 92 These data suggest a model wherein the Pin1-mediated phosphorylation of NL-2 drives conformational changes that detach gephyrin from NL-2.…”

“…91 The ability of gephyrin to interact with GlyR was significantly decreased in Pin1-deficient mice, reducing the number of GlyR clusters. 91 Recently, the inhibitory synaptic adhesion molecule, NL-2, was also shown to be a substrate for Pin1, 92 which negatively regulates the interaction of gephyrin with NL-2 by phosphorylating the serine 714 residue. In addition, the absence of Pin1 was found to promote the formation of NL-2/gephyrin complexes, enrich GABA A receptors at inhibitory synaptic sites and inhibit synaptic transmission.…”

Pin1 Modulates the Synaptic Content of NMDA Receptors via Prolyl-Isomerization of PSD-95

“…They were transiently transfected with various plasmids using polyethylenimine linear (Polysciences) and collected 24 -48 h after transfection. Pin1 ϩ/ϩ and Pin1 Ϫ/Ϫ primary hippocampal neurons were prepared as previously described (Antonelli et al, 2014) from either sex. For transfection experiments mouse hippocampal neurons were transiently transfected with the indicated plasmids using Effectene (Qiagen) according to the manufacturer's protocol.…”

“…At inhibitory synapses, Pin1-dependent isomerization of gephyrin, the functional homolog of PSD-95 at inhibitory synapses, affects GlyRs function (Zita et al, 2007). At GABAergic synapses, Pin1 recruitment by the cell adhesion molecule neuroligin2 negatively modulates its ability to complex with gephyrin, leading to a downregulation of GABAergic transmission (Antonelli et al, 2014). At glutamatergic synapses Pin1 has been detected in dendritic shafts and spines where it acts by suppressing protein synthesis required to sustain the late phase of long-term potentiation (LTP; Westmark et al, 2010).…”

Structure and function of the human parvulins Pin1 and Par14/17

“…Subsequent reactions are often the initiation or prevention of PTM processes such as ubiquitination (Siepe and Jentsch, 2009) or conformer-specific protein-protein interactions . Depending on this outcome Pin1 could enhance (Lee et al, 2009b) or weaken Eckerdt et al, 2005;Luo et al, 2010;Khanal et al, 2012) protein stability and influence protein turn-over; it can drive protein cascades in signaling events (Keune et al, 2013;Toko et al, 2013;Antonelli et al, 2014;So and Oh, 2015;Rustighi et al, 2017) or regulate metabolic processes such as the insulin dependent glucose uptake (Nakatsu et al, 2009).…”