ALBERT

Description: 〈p〉Publication date: 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Cell Reports, Volume 28, Issue 7〈/p〉 〈p〉Author(s): Alexander J. Baker-Williams, Fiza Hashmi, Marek A. Budzyński, Mark R. Woodford, Stephanie Gleicher, Samu V. Himanen, Alan M. Makedon, Derek Friedman, Stephanie Cortes, Sara Namek, William G. Stetler-Stevenson, Gennady Bratslavsky, Alaji Bah, Mehdi Mollapour, Lea Sistonen, Dimitra Bourboulia〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉The extracellular molecular chaperone heat shock protein 90 (eHSP90) stabilizes protease client the matrix metalloproteinase 2 (MMP2), leading to tumor cell invasion. Although co-chaperones are critical modulators of intracellular HSP90:client function, how the eHSP90:MMP2 complex is regulated remains speculative. Here, we report that the tissue inhibitor of metalloproteinases-2 (TIMP2) is a stress-inducible extracellular co-chaperone that binds to eHSP90, increases eHSP90 binding to ATP, and inhibits its ATPase activity. In addition to disrupting the eHSP90:MMP2 complex and terminally inactivating MMP2, TIMP2 loads the client to eHSP90, keeping the protease in a transient inhibitory state. Secreted activating co-chaperone AHA1 displaces TIMP2 from the complex, providing a “reactivating” mechanism for MMP2. Gene knockout or blocking antibodies targeting TIMP2 and AHA1 released by HT1080 cancer cells modify their gelatinolytic activity. Our data suggest that TIMP2 and AHA1 co-chaperones function as a molecular switch that determines the inhibition and reactivation of the eHSP90 client protein MMP2.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2211124719309490-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉