Article

  • The EMBO Journal (2007) 26, 855 - 866
  • doi:10.1038/sj.emboj.7601528

Published online: 25 January 2007

Impaired post-translational folding of familial ALS-linked Cu, Zn superoxide dismutase mutants

Cami K Bruns1 and Ron R Kopito1

  1. Department of Biological Sciences, Stanford University, Stanford, CA, USA

Correspondence to:

Ron R Kopito, Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA. Tel.: +1 650 723 7581; Fax: +1 650 724 9975; E-mail: kopito@stanford.edu

Received 20 October 2006; Accepted 5 December 2006


Over 110 structurally diverse missense mutations in the superoxide dismutase (SOD1) gene have been linked to the pathogenesis of familial amyotrophic lateral sclerosis (FALS), yet the mechanism by which these lead to cytotoxicity still remains unknown. We have synthesized wild-type and mutant SOD1 in synchronized cell-free reticulocyte extracts replete with the full complement of molecular chaperones and folding facilitators that are normally required to fold this metalloenzyme. Here, we report that, despite being a small, single-domain protein, human SOD1 folds post-translationally to a hyperstable native-like conformation without a requirement for ATP-dependent molecular chaperones. SOD1 folding requires tight Zn but not Cu binding and proceeds through at least three kinetically and biochemically distinct states. We find that all 11 FALS-associated SOD1 mutants examined using this system delay the kinetics of folding, but do not necessarily preclude the formation of native-like states. These data suggest a model whereby impaired post-translational folding increases the population of on- and off-pathway folding intermediates that could provide an important source of proto-toxic protein, and suggest a unifying mechanism for SOD1-linked FALS pathogenesis.

  • Keywords:

    • Amyotrophic lateral sclerosis,
    • cell-free protein synthesis,
    • protein folding,
    • superoxide dismutase
Top

MORE ARTICLES LIKE THIS

These links to content published by NPG are automatically generated

NEWS AND VIEWS

Oxidation versus aggregation ? how do SOD1 mutants cause ALS?

Nature Medicine News and Views (01 Dec 2000)