FIGURE 2.

Talin as a memory molecule. (A) Talin is comprised of an N-terminal FERM domain that binds to integrin, connected to 13 helical bundles, the talin rod domains R1-R13. (B) A mechanical binary switch. One talin helical bundle is shown. Under tension each bundle can exist in two thermodynamically stable states, folded “0” and unfolded “1” and can be switched back and forth between these states via mechanical force. (C) Cartoon of three rod domains going from 000 to 010 in response to one contractility spike by the cytoskeletal force-generation machinery. (D) A talin molecule as a binary string, the nine vinculin binding sites are labelled in green (i) in the absence of force the 13 rod domains are all in the folded “0” state; (ii) upon adhesion formation each talin is tethered between the integrin:ECM and F-actin, and adopts a specific switch pattern; two contractility spikes (shown as a blue spring) result in two of the switches switching (iii and iv), whereas a decrease in contractility resets one switch back to 0 (v). The exact order of switching and the resulting switch state will depend on the system.