Mechano-Regulated Interactions between Tissue Transglutaminase 2 and Fibrillar Fibronectin: Elucidating the Binding Interface and the Mechanism
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Author
Date
2023Type
- Doctoral Thesis
ETH Bibliography
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Abstract
Transglutaminase 2 (TG2) plays a vital role in stabilizing extracellular matrix (ECM) proteins through enzymatic crosslinking during tissue growth, repair, and inflammation. TG2 also binds non-covalently to fibronectin (FN), an essential component of the ECM, facilitating cell adhesion, migration, proliferation, and survival. However, the interaction between TG2 and fibrillar FN remains poorly understood, as most studies have focused on soluble or surface-adsorbed FN or FN fragments, which differ in their conformations from insoluble FN fibers. Using a well-established in vitro FN fiber stretch assay, we discovered that the binding of a crosslinking enzyme to ECM fibers is mechano-regulated. TG2 binding to FN is tuned by the mechanical tension of FN fibers, whereby TG2 predominantly co-localizes to low-tension FN fibers, while fiber stretching reduces their affinity for TG2. This mechano-regulated binding relies on the proximity between the N-terminal β-sandwich and C-terminal β-barrels of TG2. Crosslinking mass spectrometry (XL-MS) revealed a novel TG2-FN synergy site within TG2’s C-terminal β-barrels that interacts with FN regions located outside of the canonical gelatin binding domain, specifically FNI2 and FNIII14–15. Combining XL-MS distance restraints with molecular docking revealed the mechano-regulated binding mechanism between TG2 and modules FNI7–9 by which mechanical forces regulate TG2-FN interactions. This highlights a previously unrecognized role of TG2 as a tension sensor for FN fibers. This novel interaction mechanism has significant implications in physiology and mechanobiology, including how forces regulate cell adhesion, spreading, migration, phenotype modulation, depending on the tensional state of ECM fibers. Data are available via ProteomeXchange with identifier PXD043976. Show more
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https://doi.org/10.3929/ethz-b-000654849Publication status
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Contributors
Examiner: Vogel, Viola
Examiner: Leitner, Alexander
Examiner: Verderio Edwards, Elisabetta
Publisher
ETH ZurichSubject
Mechanobiology; extracellular matrix; EXTRACELLULAR MATRIX PROTEINS; transglutaminase 2; Fibronectin; FRET (fluorescence resonance energy transfer); FRET-based molecular tension sensors; Protein-protein interactionsOrganisational unit
03640 - Vogel, Viola / Vogel, Viola
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ETH Bibliography
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