Identification of protein interfaces between α-synuclein, the principal component of Lewy bodies in Parkinson disease, and the molecular chaperones human Hsc70 and the yeast Ssa1p.

Virginie Redeker, Samantha Pemberton, Willy Bienvenut, Luc Bousset, Ronald Melki

The Journal of biological chemistry 2012 Sep 21

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Fibrillar α-synuclein (α-Syn) is the principal component of Lewy bodies, which are evident in individuals affected by Parkinson disease (PD). This neuropathologic form of α-Syn plays a central role in PD progression as it has been shown to propagate between neurons. Tools that interfere with α-Syn assembly or change the physicochemical properties of the fibrils have potential therapeutic properties as they may be sufficient to interfere with and/or halt cell-to-cell transmission and the systematic spread of α-Syn assemblies within the central nervous system. Vertebrate molecular chaperones from the constitutive/heat-inducible heat shock protein 70 (Hsc/p70) family have been shown to hinder the assembly of soluble α-Syn into fibrils and to bind to the fibrils and very significantly reduce their toxicity. To understand how Hsc70 family members sequester soluble α-Syn, we set up experiments to identify the molecular chaperone-α-Syn surface interfaces. We cross-linked human Hsc70 and its yeast homologue Ssa1p and α-Syn using a chemical cross-linker and mapped the Hsc70- and Ssa1p-α-Syn interface. We show that the client binding domain of Hsc70 and Ssa1p binds two regions within α-Syn similar to a tweezer, with the first spanning residues 10-45 and the second spanning residues 97-102. Our findings define what is necessary and sufficient for engineering Hsc70- and Ssa1p-derived polypeptide with minichaperone properties with a potential as therapeutic agents in Parkinson disease through their ability to affect α-Syn assembly and/or toxicity.

Citation

Virginie Redeker, Samantha Pemberton, Willy Bienvenut, Luc Bousset, Ronald Melki. Identification of protein interfaces between α-synuclein, the principal component of Lewy bodies in Parkinson disease, and the molecular chaperones human Hsc70 and the yeast Ssa1p. The Journal of biological chemistry. 2012 Sep 21;287(39):32630-9