Membrane tension determines the geometry of donut-shaped transcellular holes

Abstract

Bacteria and leukocytes employ donut-shaped transcellular holes in plasma membrane to cross the endothelial barrier. How these fused holes are regulated in a double-bilayer system is currently poorly understood. Here we use membrane physics to present a universal relationship that determines the geometry of the donut-shaped holes. Our study reveals that hole radius is determined by plasma membrane tension via a commonly used critical length scale $\sqrt{\kappa /\lambda }$ defined by flexural stiffness ( $\kappa$ ) and in-plane tension ( $\lambda$ ). This relationship suggests that the hole diameter increases with a reduction in membrane tension, a finding aligned with the experimental observations but in contrast with the main current model in the literature.