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Campbell MR, Ruiz-Saenz A, Zhang Y, Peterson E, Steri V, Oeffinger J, Sampang M, Jura N, Moasser MM. Extensive conformational and physical plasticity protects HER2-HER3 tumorigenic signaling. Cell Rep 2022; 38:110285. [PMID: 35108526 PMCID: PMC8865943 DOI: 10.1016/j.celrep.2021.110285] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 08/30/2021] [Accepted: 12/28/2021] [Indexed: 12/13/2022] Open
Abstract
Surface-targeting biotherapeutic agents have been successful in treating HER2-amplified cancers through immunostimulation or chemodelivery but have failed to produce effective inhibitors of constitutive HER2-HER3 signaling. We report an extensive structure-function analysis of this tumor driver, revealing complete uncoupling of intracellular signaling and tumorigenic function from regulation or constraints from their extracellular domains (ECDs). The canonical HER3 ECD conformational changes and exposure of the dimerization interface are nonessential, and the entire ECDs of HER2 and HER3 are redundant for tumorigenic signaling. Restricting the proximation of partner ECDs with bulk and steric clash through extremely disruptive receptor engineering leaves tumorigenic signaling unperturbed. This is likely due to considerable conformational flexibilities across the span of these receptor molecules and substantial undulations in the plane of the plasma membrane, none of which had been foreseen as impediments to targeting strategies. The massive overexpression of HER2 functionally and physically uncouples intracellular signaling from extracellular constraints.
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Affiliation(s)
- Marcia R Campbell
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ana Ruiz-Saenz
- Departments of Cell Biology & Medical Oncology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Yuntian Zhang
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Elliott Peterson
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Veronica Steri
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Julie Oeffinger
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Maryjo Sampang
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Natalia Jura
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Mark M Moasser
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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