Access

Article

Nature Immunology 7, 625–633 (1 June 2006) | doi:10.1038/ni1337

Quantitative proteomic analysis of B cell lipid rafts reveals that ezrin regulates antigen receptor|[ndash]|mediated lipid raft dynamics

Neetu Gupta , Bernd Wollscheid , Julian D Watts , Barbara Scheer , Ruedi Aebersold & Anthony L DeFranco

Ligation of the B cell antigen receptor (BCR) with antigen induces lipid raft coalescence, a process that occurs after crosslinking of a variety of signaling receptors and is thought to potentiate cellular activation. To investigate lipid raft dynamics during BCR signaling, we quantitatively analyzed the B cell lipid raft proteome. BCR engagement induced dissociation of the adaptor protein ezrin from lipid rafts as well as threonine dephosphorylation of ezrin and its concomitant detachment from actin, indicating a transient uncoupling of lipid rafts from the actin cytoskeleton. Expression of constitutively active ezrin chimeras inhibited the BCR-induced coalescence of lipid rafts. Our data demonstrate that the release of ezrin from lipid rafts acts as a critical trigger that regulates lipid raft dynamics during BCR signaling.