C-terminal oligomerization of podocin mediates interallelic interactions

Pál Stráner, Eszter Balogh, Gusztáv Schay, Christelle Arrondel, Ágnes Mikó, Gerda L'Auné, Alexandre Benmerah, András Perczel, Dóra K. Menyhárd, Corinne Antignac, Géraldine Mollet, Kálmán Tory

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4 Citations (Scopus)

Abstract

Interallelic interactions of membrane proteins are not taken into account while evaluating the pathogenicity of sequence variants in autosomal recessive disorders. Podocin, a membrane-anchored component of the slit diaphragm, is encoded by NPHS2, the major gene mutated in hereditary podocytopathies. We formerly showed that its R229Q variant is only pathogenic when trans-associated to specific 3′ mutations and suggested the causal role of an abnormal C-terminal dimerization. Here we show by FRET analysis and size exclusion chromatography that podocin oligomerization occurs exclusively through the C-terminal tail (residues 283–382): principally through the first C-terminal helical region (H1, 283–313), which forms a coiled coil as shown by circular dichroism spectroscopy, and through the 332–348 region. We show the principal role of the oligomerization sites in mediating interallelic interactions: while the monomer-forming R286Tfs*17 podocin remains membranous irrespective of the coexpressed podocin variant identity, podocin variants with an intact H1 significantly influence each other's localization (r2 = 0.68, P = 9.2 × 10−32). The dominant negative effect resulting in intracellular retention of the pathogenic F344Lfs*4-R229Q heterooligomer occurs in parallel with a reduction in the FRET efficiency, suggesting the causal role of a conformational rearrangement. On the other hand, oligomerization can also promote the membrane localization: it can prevent the endocytosis of F344Lfs*4 or F344* podocin mutants induced by C-terminal truncation. In conclusion, C-terminal oligomerization of podocin can mediate both a dominant negative effect and interallelic complementation. Interallelic interactions of NPHS2 are not restricted to the R229Q variant and have to be considered in compound heterozygous individuals.

Original languageEnglish
Pages (from-to)2448-2457
Number of pages10
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1864
Issue number7
DOIs
Publication statusPublished - Jul 2018

Keywords

  • Complementation
  • Dominant negative effect
  • Endocytosis
  • Membrane targeting
  • Nephrotic syndrome
  • Podocin

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology

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  • Cite this

    Stráner, P., Balogh, E., Schay, G., Arrondel, C., Mikó, Á., L'Auné, G., Benmerah, A., Perczel, A., K. Menyhárd, D., Antignac, C., Mollet, G., & Tory, K. (2018). C-terminal oligomerization of podocin mediates interallelic interactions. Biochimica et Biophysica Acta - Molecular Basis of Disease, 1864(7), 2448-2457. https://doi.org/10.1016/j.bbadis.2018.04.008