Structural modeling predicts altered disulfide connectivity in HER2 W452C.
4 affiliations
- 1Center for Precision Medicine and Data Sciences, University of California, Davis, School of Medicine, Sacramento, CA, USA.
- 2Department of Physiology and Membrane Biology, University of California, Davis, School of Medicine, Davis, CA, USA.
- 3Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, CA, USA.
- 4Department of Pharmacology, University of California, Davis, School of Medicine, Davis, CA, USA.
Abstract
HER2, an ERBB2-encoded receptor tyrosine kinase, regulates cell growth and survival. HER2 overexpression or ERBB2 amplification can promote tumor growth and is used to identify cancers that may benefit from HER2-targeted therapies. However, the functional consequences of sequence variants are difficult to predict when they occur outside known functional sites. Cysteine-introducing variants pose a challenge because a new cysteine can either form an abnormal bond directly or disrupt an existing disulfide and change which interactions are possible. HER2 W452C variant provides a case study of this problem because it introduces a cysteine outside the canonical dimerization interface but near a native extracellular disulfide. We used structural modeling, molecular dynamics, protein-protein docking, and cell-based analysis to test how W452C could alter receptor organization. Direct C452-C452 pairing between HER2 receptors was consistently difficult to accommodate without severe receptor overlap. We therefore examined a conditional state in which the native disulfide was reorganized, leaving another cysteine available for intermolecular interaction. This state increased ectodomain flexibility and accommodated alternative cysteine-mediated contacts. Explicit-bond refinement showed that selected C452-C504 arrangements remained structurally compatible after covalent disulfide formation. In cells, W452C increased a DTT-sensitive high-molecular-weight HER2-containing species, supporting altered disulfide-dependent association. Together, these findings support a mechanism in which an introduced cysteine alters receptor organization by reorganizing the local disulfide network rather than simply forming a new bond itself. More broadly, they illustrate how structural analysis can reveal molecular consequences of genetic variants that are not apparent from sequence position alone and thereby inform precision-medicine variant interpretation.
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BibTeX
@article{ngo2026structural,
title = {{Structural modeling predicts altered disulfide connectivity in HER2 W452C.}},
author = {Khoa Ngo and Matthew Saldaña and Hajar Amini and Kermit L Carraway and Colleen E Clancy},
journal = {Journal of precision medicine (Amsterdam, Netherlands)},
year = {2026},
month = oct,
doi = {10.1016/j.premed.2026.100064},
url = {https://europepmc.org/article/MED/42948421},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Structural modeling predicts altered disulfide connectivity in HER2 W452C.
AU - Khoa Ngo
AU - Matthew Saldaña
AU - Hajar Amini
AU - Kermit L Carraway
AU - Colleen E Clancy
PY - 2026
DA - 2026/10/07
JO - Journal of precision medicine (Amsterdam, Netherlands)
DO - 10.1016/j.premed.2026.100064
UR - https://europepmc.org/article/MED/42948421
AB - HER2, an ERBB2-encoded receptor tyrosine kinase, regulates cell growth and survival. HER2 overexpression or ERBB2 amplification can promote tumor growth and is used to identify cancers that may benefit from HER2-targeted therapies. However, the functional consequences of sequence variants are difficult to predict when they occur outside known functional sites. Cysteine-introducing variants pose a challenge because a new cysteine can either form an abnormal bond directly or disrupt an existing disulfide and change which interactions are possible. HER2 W452C variant provides a case study of this problem because it introduces a cysteine outside the canonical dimerization interface but near a native extracellular disulfide. We used structural modeling, molecular dynamics, protein-protein docking, and cell-based analysis to test how W452C could alter receptor organization. Direct C452-C452 pairing between HER2 receptors was consistently difficult to accommodate without severe receptor overlap. We therefore examined a conditional state in which the native disulfide was reorganized, leaving another cysteine available for intermolecular interaction. This state increased ectodomain flexibility and accommodated alternative cysteine-mediated contacts. Explicit-bond refinement showed that selected C452-C504 arrangements remained structurally compatible after covalent disulfide formation. In cells, W452C increased a DTT-sensitive high-molecular-weight HER2-containing species, supporting altered disulfide-dependent association. Together, these findings support a mechanism in which an introduced cysteine alters receptor organization by reorganizing the local disulfide network rather than simply forming a new bond itself. More broadly, they illustrate how structural analysis can reveal molecular consequences of genetic variants that are not apparent from sequence position alone and thereby inform precision-medicine variant interpretation.
SN - 3050-6328
ER -