A new mode of moving

The well-described mechanism of movement by fibroblasts and other flat cells is characterized by outstretched lamellipodia, which are attached through focal adhesions, and retraction of a trailing edge. But how lymphocytes move up to 100-times faster has been unclear. On page 141, Smith et al. report that T cells have a zone of clustered high-affinity LFA-1 integrin (α_Lβ₂) at the midzone of the cell, and that disruption of the pattern by removal of talin reduces the speed of cell migration.

When T cells contact a monolayer of cells expressing ICAM-1, activated LFA-1 concentrates in the midzone of the cells, a region that the researchers referred to as the “focal zone.” The concentrated active LFA-1 in this focal zone colocalized with bound ICAM-1 in the supporting...