figshare
Browse
Ramsay_et_al_2016.pdf (791.26 kB)

Structural analysis of X-Linked Retinoschisis mutations reveals distinct classes which differentially effect retinoschisin function

Download (791.26 kB)
journal contribution
posted on 2023-07-26, 13:59 authored by Ewan P. Ramsay, Richard F. Collins, Thomas W. Owens, C. Alistair Siebert, Richard P. O. Jones, Tao Wang, Alan M. Roseman, Clair Baldock
Retinoschisin, an octameric retinal-specific protein, is essential for retinal architecture with mutations causing X-linked retinoschisis (XLRS), a monogenic form of macular degeneration. Most XLRS-associated mutations cause intracellular retention, however a subset are secreted as octamers and the cause of their pathology is ill-defined. Therefore, here we investigated the solution structure of the retinoschisin monomer and the impact of two XLRS-causing mutants using a combinatorial approach of biophysics and cryo-EM. The retinoschisin monomer has an elongated structure which persists in the octameric assembly. Retinoschisin forms a dimer of octamers with each octameric ring adopting a planar propeller structure. Comparison of the octamer with the hexadecamer structure indicated little conformational change in the retinoschisin octamer upon dimerization, suggesting that the octamer provides a stable interface for construction of the hexadecamer. The H207Q XLRS-associated mutation was found in the interface between octamers and destabilized both monomeric and octameric retinoschisin. Octamer dimerization is consistent with the adhesive function of retinoschisin supporting interactions between retinal cell layers, so disassembly would prevent structural coupling between opposing membranes. In contrast, cryo-EM structural analysis of the R141H mutation at ~4.2Å resolution was found to only cause a subtle conformational change in the propeller tips, potentially perturbing an interaction site. Together, these findings support distinct mechanisms of pathology for two classes of XLRS-associated mutations in the retinoschisin assembly.

History

Refereed

  • Yes

Volume

25

Issue number

24

Page range

5311-5320

Publication title

Human Molecular Genetics

ISSN

1460-2083

Publisher

Oxford University Press

File version

  • Published version

Language

  • eng

Legacy posted date

2016-11-11

Legacy creation date

2016-11-10

Legacy Faculty/School/Department

ARCHIVED Faculty of Science & Technology (until September 2018)

Note

The HMG Advance Access version (not this version) was first published on October 23, 2016. © The Author 2016. Published by Oxford University Press as an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |The dataset underpinning the findings described in this paper can be accessed at : https://www.rcsb.org/pdb/explore/explore.do?structureId=5N6W |

Usage metrics

    ARU Outputs

    Categories

    No categories selected

    Licence

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC