@article{AtakLanglhoferSchaeferetal.2015,
  author    = {Atak, Sinem and Langlhofer, Georg and Schaefer, Natascha and Kessler, Denise and Meiselbach, Heike and Delto, Carolyn and Schindelin, Hermann and Villmann, Carmen},
  title     = {Disturbances of ligand potency and enhanced degradation of the human glycine receptor at affected positions G160 and T162 originally identified in patients suffering from hyperekplexia},
  series = {Frontiers in Molecular Neuroscience},
  volume    = {8},
  journal   = {Frontiers in Molecular Neuroscience},
  number    = {79},
  doi       = {10.3389/fnmol.2015.00079},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-144818},
  year      = {2015},
  abstract  = {Ligand-binding of Cys-loop receptors is determined by N-terminal extracellular loop structures from the plus as well as from the minus side of two adjacent subunits in the pentameric receptor complex. An aromatic residue in loop B of the glycine receptor (GIyR) undergoes direct interaction with the incoming ligand via a cation-π interaction. Recently, we showed that mutated residues in loop B identified from human patients suffering from hyperekplexia disturb ligand-binding. Here, we exchanged the affected human residues by amino acids found in related members of the Cys-loop receptor family to determine the effects of side chain volume for ion channel properties. GIyR variants were characterized in vitro following transfection into cell lines in order to analyze protein expression, trafficking, degradation and ion channel function. GIyR α1 G160 mutations significantly decrease glycine potency arguing for a positional effect on neighboring aromatic residues and consequently glycine-binding within the ligand-binding pocket. Disturbed glycinergic inhibition due to T162 α1 mutations is an additive effect of affected biogenesis and structural changes within the ligand-binding site. Protein trafficking from the ER toward the ER-Golgi intermediate compartment, the secretory Golgi pathways and finally the cell surface is largely diminished, but still sufficient to deliver ion channels that are functional at least at high glycine concentrations. The majority of T162 mutant protein accumulates in the ER and is delivered to ER-associated proteasomal degradation. Hence, G160 is an important determinant during glycine binding. In contrast, 1162 affects primarily receptor biogenesis whereas exchanges in functionality are secondary effects thereof.},
  language  = {en}
}
@article{AppeltshauserBrunderHeiniusetal.2020,
  author    = {Appeltshauser, Luise and Brunder, Anna-Michelle and Heinius, Annika and K{\"o}rtv{\´e}lyessy, Peter and Wandinger, Klaus-Peter and Junker, Ralf and Villmann, Carmen and Sommer, Claudia and Leypoldt, Frank and Doppler, Kathrin},
  title     = {Antiparanodal antibodies and IgG subclasses in acute autoimmune neuropathy},
  series = {Neurology: Neuroimmunology \& Neuroinflammation},
  volume    = {7},
  journal   = {Neurology: Neuroimmunology \& Neuroinflammation},
  number    = {5},
  doi       = {10.1212/NXI.0000000000000817},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230079},
  year      = {2020},
  abstract  = {Objective To determine whether IgG subclasses of antiparanodal autoantibodies are related to disease course and treatment response in acute- to subacute-onset neuropathies, we retrospectively screened 161 baseline serum/CSF samples and 66 follow-up serum/CSF samples. Methods We used ELISA and immunofluorescence assays to detect antiparanodal IgG and their subclasses and titers in serum/CSF of patients with Guillain-Barre syndrome (GBS), recurrent GBS (R-GBS), Miller-Fisher syndrome, and acute- to subacute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP). We evaluated clinical data retrospectively. Results We detected antiparanodal autoantibodies with a prevalence of 4.3\% (7/161), more often in A-CIDP (4/23, 17.4\%) compared with GBS (3/114, 2.6\%). Longitudinal subclass analysis in the patients with GBS revealed IgG2/3 autoantibodies against Caspr-1 and against anti-contactin-1/Caspr-1, which disappeared at remission. At disease onset, patients with A-CIDP had IgG2/3 anti-Caspr-1 and anti-contactin-1/Caspr-1 or IgG4 anti-contactin-1 antibodies, IgG3 being associated with good response to IV immunoglobulins (IVIg). In the chronic phase of disease, IgG subclass of one patient with A-CIDP switched from IgG3 to IgG4. Conclusion Our data (1) confirm and extend previous observations that antiparanodal IgG2/3 but not IgG4 antibodies can occur in acute-onset neuropathies manifesting as monophasic GBS, (2) suggest association of IgG3 to a favorable response to IVIg, and (3) lend support to the hypothesis that in some patients, an IgG subclass switch from IgG3 to IgG4 may be the correlate of a secondary progressive or relapsing course following a GBS-like onset.},
  language  = {en}
}