Force History Dependence of Receptor-Ligand Dissociation

Abstract

Receptor-ligand bonds that mediate cell adhesion are often subjected to forces that regulate their dissociation via modulating off-rates. Off-rates control how long receptor-ligand bonds last and how much force they withstand. One should therefore be able to determine off-rates from either bond lifetime or unbinding force measurements. However, substantial discrepancies exist between the force dependence of off-rates derived from the two types of measurements even for the same interactions, e.g., selectins dissociating from their ligands, which mediate the tethering and rolling of leukocytes on vascular surfaces during inflammation and immune surveillance. We used atomic force microscopy to measure survival times of P-selectin dissociating from P-selectin glycoprotein ligand 1 or from an antibody in both bond lifetime and unbinding force experiments. By a new method of data analysis, we showed that the discrepancies resulted from the assumption that off-rates were functions of force only. The off-rates derived from forced dissociation data depended not only on force but also on the history of force application. This finding provides a new paradigm for understanding how force regulates receptor-ligand interactions.

Regulation of Catch Bonds by Rate of Force Application

“…Soluble recombinant monomeric PSGL-1 without (sPSGL-1) (9, 13) or with (PSGL-1) (36) a C-terminal biotin tag as well as biotinylated 6-sulfo-sLe x and 2-GSP-6 (15) have been described. PSGL-1 blocking (PL1) and capturing (PL2) (13,30) as well as L-selectin blocking (DREG-56) mAbs (9) have been described. Human Fc capturing mouse mAb (GG-7) and goat polyclonal antibody were from Sigma-Aldrich and Chemicon, respectively.…”

“…Even for unfolding of the von Willebrand factor A2 domain, force clamp measurements observed catch-slip bonds (28), and DFS measurements observed slip bonds (29). These discrepancies persisted even when the two types of measurements were made in the same laboratories by the same experimenters using the same instruments with the same reagents (21,30).…”

“…k Ϫ1 at t is a functional of all values of f in the past times up to the present time t, not just its present value at t (30). This new concept should not be confused with the concept of ramp rate-dependent rupture forces.…”

Atomic Force Spectroscopies: A Toolbox for Probing the Biological Matter

“…Off-rates control how long receptorligand bonds last and how much force they withstand. The off-rates derived from forced dissociation data depend both on the force and on the history of force application (Kong et al, 2009;Marshall et al, 2005).…”

Surface-bound selectin–ligand binding is regulated by carrier diffusion

“…2D dissociation kinetics (Hammer and Lauffenburger 1987;Alon et al 1995;Chen et al 1997) and forced bond rupture (Florin et al 1994;Dammer et al 1996;Tees et al 2001) as well as their regulating factors (Evans et al 2001;Levin et al 2001;Huang et al 2004;Marshall et al 2005;Wu et al 2007) have been investigated theoretically and experimentally using various approaches or assays, e.g., flow chamber (Kaplanski et al 1993;Alon et al 1995;Finger et al 1996;Yago et al 2007;Paschall et al 2008), biomembrane force probe (BFP) (Evans et al 2001;Evans and Ritchie 1997), atom force microscopy (AFM) (Fritz et al 1998;Merkel et al 1999;Marshall et al 2005;Lü et al 2006), micropipette aspiration (Chesla et al 1998;Long et al 2001;Shao and Xu 2002), optical tweezers (Kulin et al 2002;Rinko et al 2004), fluorescence recovery after photobleaching (FRAP) (Dustin et al 1996;Tolentino et al 2008). Only a few works, however, were focused on quantifying 2D association kinetics mainly due to theoretical and technical limitations.…”