Modulation of gephyrin-glycine receptor affinity by multivalency

TY - JOUR

T1 - Modulation of gephyrin-glycine receptor affinity by multivalency

AU - Maric, Hans-Michael

AU - Kasaragod, Vikram Babu

AU - Schindelin, Hermann

PY - 2014/11/21

Y1 - 2014/11/21

N2 - Gephyrin is a major determinant for the accumulation and anchoring of glycine receptors (GlyRs) and the majority of γ-aminobutyric acid type A receptors (GABAARs) at postsynaptic sites. Here we explored the interaction of gephyrin with a dimeric form of a GlyR -subunit receptor-derived peptide. A 2 Å crystal structure of the C-terminal domain of gephyrin (GephE) in complex with a 15-residue peptide derived from the GlyR -subunit defined the core binding site, which we targeted with the dimeric peptide. Biophysical analyses via differential scanning calorimetry (DSC), thermofluor, and isothermal titration calorimetry (ITC) demonstrated that this dimeric ligand is capable of binding simultaneously to two receptor binding sites and that this multivalency results in a 25-fold enhanced affinity. Our study therefore suggests that the oligomeric state of gephyrin and the number of gephyrin-binding subunits in the pentameric GABAARs and GlyRs together control postsynaptic receptor clustering.

AB - Gephyrin is a major determinant for the accumulation and anchoring of glycine receptors (GlyRs) and the majority of γ-aminobutyric acid type A receptors (GABAARs) at postsynaptic sites. Here we explored the interaction of gephyrin with a dimeric form of a GlyR -subunit receptor-derived peptide. A 2 Å crystal structure of the C-terminal domain of gephyrin (GephE) in complex with a 15-residue peptide derived from the GlyR -subunit defined the core binding site, which we targeted with the dimeric peptide. Biophysical analyses via differential scanning calorimetry (DSC), thermofluor, and isothermal titration calorimetry (ITC) demonstrated that this dimeric ligand is capable of binding simultaneously to two receptor binding sites and that this multivalency results in a 25-fold enhanced affinity. Our study therefore suggests that the oligomeric state of gephyrin and the number of gephyrin-binding subunits in the pentameric GABAARs and GlyRs together control postsynaptic receptor clustering.

U2 - 10.1021/cb500303a

DO - 10.1021/cb500303a

M3 - Journal article

C2 - 25137389

SN - 1554-8929

VL - 9

SP - 2554

EP - 2562

JO - A C S Chemical Biology

JF - A C S Chemical Biology

IS - 11

ER -