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

作者：Schulte Carsten; Ferraris Gian Maria Sarra; Oldani Amanda; Galluzzi Massimiliano; Podesta Alessandro; Puricelli Luca; de Lorenzi Valentina; Lenardi Cristina; Milani Paolo; Sidenius Nicolai

来源：European Journal of Cell Biology, 2016, 95(1): 1-14.

DOI：10.1016/j.ejcb.2015.10.002

• AFM
• Focal adhesion
• Mechanotransduction
• Molecular clutch
• PIP2
• Talin
• UPAR

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.

• 出版日期2016-1