On the cover: Integrin α_Lβ₂ mediates leukocyte adhesion and migration on cells expressing the intercellular adhesion molecules (ICAMs). Transition of α_Lβ₂ from a bent conformation (illustrated) to an extended conformation is a hallmark of α_Lβ₂ activation and the opening of the α_Lβ₂ headpiece could fine regulate the binding of α_Lβ₂ to different ICAMs.Tang, X.-Y., Y.-F. Li, and S.-M. Tan. 2008. Intercellular adhesion molecule-3 binding of integrin α_Lβ₂ requires both extension and opening of the integrin headpiece. J. Immunol. 180: 4793–4804.