Journal article
Isoform heterogeneity of the human gephyrin gene (GPHN), binding domains to the glycine receptor, and mutation analysis in hyperekplexia
Journal of Biological Chemistry, Vol.278(27), pp.24688-24696
2003
Abstract
Gephyrin (GPHN) is an organizational protein that clusters and localizes the inhibitory glycine (GlyR) and GABAA receptors to the microtubular matrix of the neuronal postsynaptic membrane. Mice deficient in gephyrin develop a hereditary molybdenum cofactor deficiency and a neurological phenotype that mimics startle disease (hyperekplexia). This neuromotor disorder is associated with mutations in the GlyR α1, and β subunit genes (GLRA1 and GLRB). Further genetic heterogeneity is suspected, and we hypothesized that patients lacking mutations in GLRA1 and GLRB might have mutations in the gephyrin gene (GPHN). In addition, we adopted a yeast two-hybrid screen, using the GlyR β subunit intracellular loop as bait, in an attempt to identify further GlyR-interacting proteins implicated in hyperekplexia. Gephyrin cDNAs were isolated, and subsequent RT-PCR analysis from human tissues demonstrated the presence of five alternatively spliced GPHN exons concentrated in the central linker region of the gene. This region generated 11 distinct GPHN transcript isoforms, with 10 being specific to neuronal tissue. Mutation analysis of GPHN exons in hyperekplexia patients revealed a missense mutation (A28T) in one patient causing an amino acid substitution (N10Y). Functional testing demonstrated that GPHNN10Y does not disrupt GlyR-gephyrin interactions or collybistin-induced cell-surface clustering. We provide evidence that GlyR-gephyrin binding is dependent on the presence of an intact C-terminal MoeA homology domain. Therefore, the N10Y mutation and alternative splicing of GPHN transcripts do not affect interactions with GlyRs but may affect other interactions with the cytoskeleton or gephyrin accessory proteins.
Details
- Title
- Isoform heterogeneity of the human gephyrin gene (GPHN), binding domains to the glycine receptor, and mutation analysis in hyperekplexia
- Authors
- M I Rees (Author) - University of Auckland, New ZealandK Harvey (Author) - University College London, United KingdomH Ward (Author) - University of Auckland, New ZealandJ H White (Author) - GlaxoSmithKline Medicines Research Centre, United KingdomL Evans (Author) - University of Birmingham, United KingdomI C Duguid (Author) - University College London, United KingdomC C H Hsu (Author) - University of Auckland, New ZealandS L Coleman (Author) - University of Wales College of Medicine, United KingdomJ Miller (Author) - University of Auckland, New ZealandK Baer (Author) - University of Auckland, New ZealandH J Waldvogel (Author) - University of Auckland, New ZealandF Gibbon (Author) - University Hospital of Wales, United KingdomT G Smart (Author) - University College London, United KingdomM J Owen (Author) - University of Auckland, New ZealandRobert J Harvey (Author) - University College London, United KingdomR G Snell (Author) - University of Auckland, New Zealand
- Publication details
- Journal of Biological Chemistry, Vol.278(27), pp.24688-24696
- Publisher
- American Society for Biochemistry and Molecular Biology, Inc.
- Date published
- 2003
- DOI
- 10.1074/jbc.M301070200
- ISSN
- 0021-9258
- Copyright note
- Copyright © 2003 by the American Society for Biochemistry and Molecular Biology, Inc. The published version is reproduced here in accordance with the publisher's copyright policy.
- Organisation Unit
- School of Health; University of the Sunshine Coast, Queensland; School of Health and Sport Sciences - Legacy; Centre for Bioinnovation; School of Health and Behavioural Sciences - Legacy
- Language
- English
- Record Identifier
- 99451133902621
- Output Type
- Journal article
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