Selectin flexible cells

Leukocytes use glycoprotein ligands to grab onto selectins on blood vessel walls and roll along with the blood flow. The longer the cell can roll without detaching, the greater its chances are of responding to chemoattractants telling it to traverse the endothelium at a site of inflammation. Now, on page 787, Yago et al. show that flexibility helps a cell avoid detachment when circulatory forces are high.

As shear force increases with higher blood pressure and smaller vessel size, leukocytes can maintain a stable rolling velocity, an ability known as an automatic braking system (ABS). Artificial microspheres containing certain ligands also roll on selectins, but lack an ABS—under high forces, their rolling velocity increases, and they are more apt to detach. Recent discussion in the field has centered on whether this difference...