Post-phosphorylation prolyl isomerisation of gephyrin represents a mechanism to modulate glycine receptors function.
The microtubule binding protein gephyrin plays a prominent role in establishing and maintaining a high concentration of inhibitory glycine receptors juxtaposed to presynaptic releasing sites. Here, we show that endogenous gephyrin undergoes proline-directed phosphorylation, which is followed by the recruitment of the peptidyl-prolyl isomerase Pin1. The interaction between gephyrin and Pin1 is strictly dependent on gephyrin phosphorylation and requires serine-proline consensus sites encompassing the gephyrin proline-rich domain. Upon binding, Pin1 triggers conformational changes in the gephyrin molecule, thus enhancing its ability to bind the beta subunit of GlyRs. Consistently, a downregulation of GlyR clusters was detected in hippocampal neurons derived from Pin1 knockout mice, which was paralleled by a reduction in the amplitude of glycine-evoked currents. Our results suggest that phosphorylation-dependent prolyl isomerisation of gephyrin represents a mechanism for regulating GlyRs function.
Zita
M Moretto
MM
International School for Advanced Studies, Neuroscience Programme, Area Science Park, Basovissa SS14, 34012 Trieste, Italy.
Marchionni
Ivan
I
Bottos
Elisa
E
Righi
Massimo
M
Del Sal
Giannino
G
Cherubini
Enrico
E
Zacchi
Paola
P
D000818:Animals; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D022083:Cytoplasmic Structures / Q000378:metabolism; D000939:Epitopes; D005071:Evoked Potentials; D006624:Hippocampus / Q000166:cytology / Q000201:enzymology; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D009474:Neurons / Q000166:cytology / Q000201:enzymology; D019696:Peptidylprolyl Isomerase / Q000172:deficiency / Q000378:metabolism*; D010766:Phosphorylation; D011392:Proline / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism; D018009:Receptors, Glycine / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012694:Serine / Q000378:metabolism
D002352:Carrier Proteins; D000939:Epitopes; D008565:Membrane Proteins; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D021122:Protein Subunits; D018009:Receptors, Glycine; D011994:Recombinant Proteins; C073441:gephyrin; D012694:Serine; D011392:Proline; C000606846:PIN1 protein, human; D019696:Peptidylprolyl Isomerase; C000606850:Pin1 protein, mouse