Journal of Neurology

, Volume 265, Issue 4, pp 962–965 | Cite as

Anti-Sez6l2 antibody detected in a patient with immune-mediated cerebellar ataxia inhibits complex formation of GluR1 and Sez6l2

  • Hiroaki YaguchiEmail author
  • Ichiro Yabe
  • Hidehisa Takahashi
  • Masashi Watanabe
  • Taichi Nomura
  • Takahiro Kano
  • Masahiko Watanabe
  • Shigetsugu Hatakeyama
Letter to the Editors

Dear Sirs,

Autoantibodies are important for some cerebellar ataxias [2, 4]. We previously detected a new anti-neuronal antibody, anti-seizure-related 6 homolog like 2 (Sez6l2) antibody, in a cerebellar ataxia patient [7]. Sez6l2 is highly expressed in the hippocampus and cerebellar cortex and is one of the type 1 membrane proteins [3, 5]. We previously showed that Sez6l2 protein binds to both adducin (ADD) and glutamate receptor 1 (GluR1) and that Sez6l2 may be a modulator of AMPA receptor function via the regulation of ADD phosphorylation [8]. Our previous results indicate that Sez6l2 is one of the auxiliary subunits of the AMPA receptor and acts as a scaffolding protein to link GluR1 to ADD [8]. GluR1 is an important protein constructing the AMPA receptor, which is one of the target receptors for autoimmune-mediated neurological diseases [1]. Furthermore, we previously showed that Sez6l2 and GluR1 directly bind using their extracellular domains and that the patient’s serum...



We are grateful to Prof. Hidenao Sasaki for helpful comments. We thank Shoko Shimizu for preparation of this manuscript. This work was supported by JSPS KAKENHI Grant number 25893006.

Author contributions

HY, IY and HT designed and performed experiments, analyzed and interpreted data and drafted the manuscript and figures. MW, TN, TK, MW and SH conceived and designed the study and critically revised the manuscript. All authors have seen and agree with the content of the manuscript. HY and IY contributed equally to this work.

Compliance with ethical standards

Conflicts of interest

All authors state that there is no conflict of interest.

Ethical approval

This study was approved by the Institutional Review Board of Hokkaido University Hospital.

Informed consent

Written informed consent was obtained from the patient (Protocol number 012-0167).

Supplementary material

415_2018_8785_MOESM1_ESM.eps (21.8 mb)
Supplementary material 1 (EPS 22285 kb) Supplemental Fig. 1. Immunofluorescence analysis using HeLa cells transfected with the extracellular domain of Sez6l2 (FLAG-Sez6l2(EX)) and the extracellular domain of GluR1 (HA-GluR1(EX)). (A) Immunofluorescence analysis of FLAG-Sez6l2(EX) and HA-GluR1(EX). The cells were fixed and stained with antibodies to FLAG (green), HA (red), and Hoechst33258 (blue). Immunofluorescence analysis using HeLa cells transfected with the extracellular domain of Sez6l2 (FLAG-Sez6l2(EX)) and the extracellular domain of GluR1 (HA-GluR1(EX)) showed co-localization of Sez6l2(EX) and GluR1(EX). (B) Immunofluorescence analysis of FLAG-Sez6l2(FL) and GluR1(FL). The cells were fixed and stained with antibodies to FLAG (green), GluR1 (red), and Hoechst33258 (blue). Immunofluorescence analysis using HeLa cells transfected with the full length of FLAG-Sez6l2 [FLAG-Sez6l2 (FL)] and the full length of GluR1(GluR1(FL)) showed partial co-localization of Sez6l2(FL) and GluR1(FL)
415_2018_8785_MOESM2_ESM.eps (2.8 mb)
Supplementary material 2 (EPS 2906 kb) Supplemental Fig. 2. Schema of “inhibition assay of direct binding between Sez6l2 and GluR1 using the patient’s serum or control serum”. Pt, patient; Ct, control; PBS, phosphate buffered saline; IP, immunoprecipitation; IB, immunoblot. Using recombinant proteins of FLAG-Sez6l2(EX) and HA-GluR1(EX) and the patient’s serum and healthy control serum, we tried to check inhibition of direct binding between Sez6l2 and GluR1. Proteins of FLAG-Sez6l2(EX) and HA-GluR1(EX) were used at the same amounts as those shown in Fig. 1. We washed each sample with PBS gently three times in every PBS wash


  1. 1.
    Hoftberger R, van Sonderen A, Leypoldt F, Houghton D, Geschwind M, Gelfand J, Paredes M, Sabater L, Saiz A, Titulaer MJ, Graus F, Dalmau J (2015) Encephalitis and AMPA receptor antibodies: novel findings in a case series of 22 patients. Neurology 84:2403–2412CrossRefPubMedPubMedCentralGoogle Scholar
  2. 2.
    Irani SR, Gelfand JM, Al-Diwani A, Vincent A (2014) Cell-surface central nervous system autoantibodies: clinical relevance and emerging paradigms. Ann Neurol 76:168–184CrossRefPubMedPubMedCentralGoogle Scholar
  3. 3.
    Ishikawa N, Daigo Y, Takano A, Taniwaki M, Kato T, Tanaka S, Yasui W, Takeshima Y, Inai K, Nishimura H, Tsuchiya E, Kohno N, Nakamura Y (2006) Characterization of SEZ6L2 cell-surface protein as a novel prognostic marker for lung cancer. Cancer Sci 97:737–745CrossRefPubMedGoogle Scholar
  4. 4.
    Mitoma H, Adhikari K, Aeschlimann D, Chattopadhyay P, Hadjivassiliou M, Hampe CS, Honnorat J, Joubert B, Kakei S, Lee J, Manto M, Matsunaga A, Mizusawa H, Nanri K, Shanmugarajah P, Yoneda M, Yuki N (2016) Consensus paper: neuroimmune mechanisms of cerebellar ataxias. Cerebellum (London, England) 15:213–232CrossRefGoogle Scholar
  5. 5.
    Miyazaki T, Hashimoto K, Uda A, Sakagami H, Nakamura Y, Saito SY, Nishi M, Kume H, Tohgo A, Kaneko I, Kondo H, Fukunaga K, Kano M, Watanabe M, Takeshima H (2006) Disturbance of cerebellar synaptic maturation in mutant mice lacking BSRPs, a novel brain-specific receptor-like protein family. FEBS Lett 580:4057–4064CrossRefPubMedGoogle Scholar
  6. 6.
    Yaguchi H, Okumura F, Takahashi H, Kano T, Kameda H, Uchigashima M, Tanaka S, Watanabe M, Sasaki H, Hatakeyama S (2012) TRIM67 protein negatively regulates Ras activity through degradation of 80K-H and induces neuritogenesis. J Biol Chem 287:12050–12059CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Yaguchi H, Yabe I, Takahashi H, Okumura F, Takeuchi A, Horiuchi K, Kano T, Kanda A, Saito W, Matsumoto M, Nakayama KI, Hatakeyama S, Sasaki H (2014) Identification of anti-Sez6l2 antibody in a patient with cerebellar ataxia and retinopathy. J Neurol 261:224–226CrossRefPubMedGoogle Scholar
  8. 8.
    Yaguchi H, Yabe I, Takahashi H, Watanabe M, Nomura T, Kano T, Matsumoto M, Nakayama KI, Watanabe M, Hatakeyama S (2017) Sez6l2 regulates phosphorylation of ADD and neuritogenesis. Biochem Biophys Res Commun 494:234–241CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Hiroaki Yaguchi
    • 1
    • 2
    • 3
    Email author
  • Ichiro Yabe
    • 1
  • Hidehisa Takahashi
    • 2
  • Masashi Watanabe
    • 2
  • Taichi Nomura
    • 3
  • Takahiro Kano
    • 1
  • Masahiko Watanabe
    • 4
  • Shigetsugu Hatakeyama
    • 2
  1. 1.Department of NeurologyHokkaido University Graduate School of MedicineSapporoJapan
  2. 2.Department of Biochemistry, Faculty of Medicine, Graduate School of MedicineHokkaido UniversitySapporoJapan
  3. 3.Department of Neurology, Brain Science CenterSapporo City General HospitalSapporoJapan
  4. 4.Department of AnatomyHokkaido University Graduate School of MedicineSapporoJapan

Personalised recommendations