TY  - JOUR
A1  - Paarmann, Ingo
A1  - Schmitt, Bertram
A1  - Meyer, Björn
A1  - Karas, Michael
A1  - Betz, Heinrich
T1  - Mass spectrometric analysis of glycine receptor-associated gephyrin splice variants
T2  - Journal of biological chemistry
N2  - Gephyrin is an ubiquitously expressed protein that, in the nervous system, is essential for synaptic anchoring of glycine receptors (GlyRs) and major GABAA receptor subtypes. The binding of gephyrin to the GlyR depends on an amphipathic motif within the large intracellular loop of the GlyRβ subunit. The mouse gephyrin gene consists of 30 exons. Ten of these exons, encoding cassettes of 5–40 amino acids, are subject to alternative splicing (C1–C7, C4′–C6′). Since one of the cassettes, C5′, has recently been reported to exclude GlyRs from GABAergic synapses, we investigated which cassettes are found in gephyrin associated with the GlyR. Gephyrin variants were purified from rat spinal cord, brain, and liver by binding to the glutathione S-transferase-tagged GlyRβ loop or copurified with native GlyR from spinal cord by affinity chromatography and analyzed by mass spectrometry. In addition to C2 and C6′, already known to be prominent, C4 was found to be abundant in gephyrin from all tissues examined. The nonneuronal cassette C3 was easily detected in liver but not in GlyR-associated gephyrin from spinal cord. C5 was present in brain and spinal cord polypeptides, whereas C5′ was coisolated mainly from liver. Notably C5′-containing gephyrin bound to the GlyRβ loop, inconsistent with its proposed selectivity for GABAA receptors. Our data show that GlyR-associated gephyrin, lacking C3, but enriched in C4 without C5, differs from other neuronal and nonneuronal gephyrin isoforms.
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76231
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-762315
SN  - 0021-9258
VL  - 281
IS  - 46
SP  - 34918
EP  - 34925
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -