Syndecan-4 tunes cell mechanics by activating the kindlin-integrin-RhoA pathway


Extensive research over the past decades has identified integrins to be the primary transmembrane receptors that enable cells to respond to external mechanical cues. We reveal here a mechanism whereby syndecan-4 tunes cell mechanics in response to localized tension via a coordinated mechanochemical signalling response that involves activation of two other receptors: epidermal growth factor receptor and β1 integrin. Tension on syndecan-4 induces cell-wide activation of the kindlin-2/β1 integrin/RhoA axis in a PI3K-dependent manner. Furthermore, syndecan-4-mediated tension at the cell–extracellular matrix interface is required for yes-associated protein activation. Extracellular tension on syndecan-4 triggers a conformational change in the cytoplasmic domain, the variable region of which is indispensable for the mechanical adaptation to force, facilitating the assembly of a syndecan-4/α-actinin/F-actin molecular scaffold at the bead adhesion. This mechanotransduction pathway for syndecan-4 should have immediate implications for the broader field of mechanobiology.

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Fig. 1: Tension on syndecan-4 induces Rho-dependent adaptive stiffening mediated by epidermal growth factor receptor (EGFR) and phosphoinositide 3-kinase (PI3K).
Fig. 2: Tension on syndecan-4 leads to PI3K-dependent cell-wide growth of focal adhesions.
Fig. 3: Tension on syndecan-4 triggers cell-wide integrin activation via PIP3 binding to kindlin-2.
Fig. 4: Tension on syndecan-4 activates RhoA via integrin ligation and regulates yes-associated protein (YAP) activity.
Fig. 5: Syndecan-4 mechanotransduction requires the V region, which changes conformation under force.
Fig. 6: Tension stabilizes a syndecan-4–α-actinin–F-actin linkage to facilitate adaptive stiffening.

Data availability

The data that support the findings of this study are available from the corresponding authors upon reasonable request.

Code availability

The MATLAB code used to track bead displacements in the magnetic tweezers experiments is available from A.E.d.R.H. upon reasonable request. Code used in the MD simulations is available from V.P.H. upon reasonable request.


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This work was supported by the European Research Council (ERC grant no. 282051), the Biotechnology and Biological Sciences Research Council (BBSRC grant no. BB/N018532/1) and the Academy of Finland (grant no. 290506). V.V.M. was supported by an EDUFI (former CIMO) postdoctoral fellowship and Academy of Finland funding for Postdoctoral Researcher (grant no. 323021). We thank M. Morgan (University of Liverpool) for providing MEF cell lines, J. Couchman (University of Copenhagen) for providing syndecan-4 cytoplasmic truncation plasmids (C2 and V domains), J. Qin (Cleveland Clinic) for the kindlin-2-GFP plasmids, C. Wu (University of Pittsburgh) for the kindlin-2 K390A plasmid and F. Di Maggio for help in implementing the initial work with PSCs. We acknowledge CSC–IT Center for Science, Finland for computational resources. We are also grateful to all CMBL members for help and advice throughout this work.

Author information

A.C. and A.J.R. conducted magnetic tweezers experiments. A.C. and S.D.T. conducted permanent magnet experiments. S.D.T. and A.C. performed and analysed experiments with MEF cells. A.C., E.C., D.L. and S.D.T. performed and analysed experiments with PSCs. S.D.T. carried out transfections and western blots, and immunofluorescent staining experiments supervised by D.A.L. E.C. carried out RhoA activity experiments. V.V.M. performed MD and SMD experiments supervised by V.P.H. and T.R. D.L. performed IF experiments and data analysis. A.C., S.D.T. and A.E.d.R.H. designed the studies and wrote and prepared the manuscript with significant input from V.P.H. All authors commented on the manuscript.

Correspondence to Stephen D. Thorpe or Vesa P. Hytönen or Armando E. del Río Hernández.

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Chronopoulos, A., Thorpe, S.D., Cortes, E. et al. Syndecan-4 tunes cell mechanics by activating the kindlin-integrin-RhoA pathway. Nat. Mater. (2020).

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