Figure 6.

Proposed mechanism for how Spy inhibits aggregation and assists protein folding in vivo. Clockwise from the bottom left (native substrate protein), exposure to chemical stress (denoted by the pink box) causes proteins in the periplasm of Escherichia coli to unfold. The stress induces the production of Spy, which rapidly associates with its substrate proteins, thereby preventing their aggregation. Once the stress is removed (denoted by the light blue box), dilution of Spy through cell growth or degradation lowers the Spy concentration, allowing the native substrate protein to be released.