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Catch bonds govern adhesion through L-selectin at threshold shear.
Tadayuki Yago1, Jianhua Wu, C Diana Wey
1Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA.
The Journal of Cell Biology
|September 15, 2004
Summary
Flow-enhanced cell adhesion, crucial for leukocyte rolling, is explained by catch bonds. These bonds strengthen under force, increasing adhesion and regulating cell movement in blood flow.
Area of Science:
- Biophysics
- Cellular Biology
- Immunology
Background:
- Flow-enhanced cell adhesion is a poorly understood phenomenon.
- Leukocyte rolling on P-selectin glycoprotein ligand-1 (PSGL-1) by L-selectin requires a threshold shear force.
- Adhesive bonds can exhibit catch bond (force-dependent decrease in off-rate) or slip bond (force-dependent increase in off-rate) behavior.
Purpose of the Study:
- To elucidate the mechanism behind flow-enhanced cell adhesion.
- To determine the role of force-dependent alterations in bond lifetimes in L-selectin-mediated cell rolling.
Main Methods:
- Utilized L-selectin-bearing microspheres and neutrophils.
- Studied rolling dynamics on PSGL-1 under varying shear forces.
- Analyzed the transition between catch bonds and slip bonds.
Main Results:
- A force-dependent decrease in off-rates (catch bonds) was identified as the key factor in flow-enhanced rolling.
- Increasing force initially converted short-lived tethers to longer-lived ones, reducing velocity and increasing rolling regularity.
- Above an optimal shear, bonds transitioned to slip bonds, shortening tether lifetimes, increasing velocity, and decreasing regularity.
Conclusions:
- Force-dependent changes in bond lifetimes govern L-selectin-dependent cell adhesion.
- Catch bonds provide the first demonstrated biological function for enhancing cell adhesion under flow conditions.