The molecular clutch (MC) model proposes that actomyosin-driven force transmission permits integrin-dependent cell migration. To investigate the MC, we introduced diverse talin (TLN) and integrin variants into Flp-In� T-Rex� HEK293 cells stably expressing uPAR. Vitronectin variants served as substrate providing uPAR-mediated cell adhesion and optionally integrin binding. This particular system allowed us to selectively analyse key MC proteins and interactions, effectively from the extracellular matrix substrate to intracellular f-actin, and to therewith study mechanobiological aspects of MC engagement also uncoupled from integrin/ligand binding. With this experimental approach, we found that for the initial PIP2-dependent membrane/TLN/f-actin linkage and persistent lamellipodia formation the C-terminal TLN actin binding site (ABS) is dispensable. The establishment of an adequate MC-mediated lamellipodial tension instead depends predominantly on the coupling of this C-terminal TLN ABS to the actomyosin-driven retrograde actin flow force. This lamellipodial tension is crucial for full integrin activation eventually determining integrin-dependent cell migration. In the integrin/ligand-independent condition the frictional membrane resistance participates to these processes. Integrin/ligand binding can also contribute but is not necessarily required.

Lamellipodial tension, not integrin/ligand binding, is the crucial factor to realise integrin activation and cell migration / C. Schulte, G.M. Sarra Ferraris, A. Oldani, M. Galluzzi, A. Podestà, L. Puricelli, V. de Lorenzi, C. Lenardi, P. Milani, N. Sidenius. - In: EUROPEAN JOURNAL OF CELL BIOLOGY. - ISSN 0171-9335. - 95:1(2016 Jan), pp. 1-14. [10.1016/j.ejcb.2015.10.002]

Lamellipodial tension, not integrin/ligand binding, is the crucial factor to realise integrin activation and cell migration

C. Schulte;G.M. Sarra Ferraris;M. Galluzzi;A. Podestà;L. Puricelli;V. de Lorenzi;C. Lenardi;P. Milani;
2016-01

Abstract

The molecular clutch (MC) model proposes that actomyosin-driven force transmission permits integrin-dependent cell migration. To investigate the MC, we introduced diverse talin (TLN) and integrin variants into Flp-In� T-Rex� HEK293 cells stably expressing uPAR. Vitronectin variants served as substrate providing uPAR-mediated cell adhesion and optionally integrin binding. This particular system allowed us to selectively analyse key MC proteins and interactions, effectively from the extracellular matrix substrate to intracellular f-actin, and to therewith study mechanobiological aspects of MC engagement also uncoupled from integrin/ligand binding. With this experimental approach, we found that for the initial PIP2-dependent membrane/TLN/f-actin linkage and persistent lamellipodia formation the C-terminal TLN actin binding site (ABS) is dispensable. The establishment of an adequate MC-mediated lamellipodial tension instead depends predominantly on the coupling of this C-terminal TLN ABS to the actomyosin-driven retrograde actin flow force. This lamellipodial tension is crucial for full integrin activation eventually determining integrin-dependent cell migration. In the integrin/ligand-independent condition the frictional membrane resistance participates to these processes. Integrin/ligand binding can also contribute but is not necessarily required.
AFM; Focal adhesion; Mechanotransduction; Molecular clutch; PIP(2); Talin; uPAR
Settore BIO/11 - Biologia Molecolare
19-ott-2015
Centro Interdisciplinare Materiali ed Interfacce Nanostrutturati - CIMAINA
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/343403
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