PI 3-kinase: A pivotal pathway in T-cell activation?

Coupling and/or activation of phosphoinositide 3-kinase (PI 3-kinase) commonly occurs following the triggering of T-cell surface molecules postulated to modulate early events in T-cell activation (e.g. CD28). Recent studies have revealed important and conflicting data as to the role of PI 3-kinase in T-cell costimulation following CD28 ligation. Here, Stephen Wara and colleagues integrate the available data and propose a role for PI 3-kinase in T-cell activation and costimulation.