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Ca 2+ signaling in antigen receptor‐activated B lymphocytes
Author(s) -
Engelke Michael,
Engels Niklas,
Dittmann Kai,
Stork Björn,
Wienands Jürgen
Publication year - 2007
Publication title -
immunological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.839
H-Index - 223
eISSN - 1600-065X
pISSN - 0105-2896
DOI - 10.1111/j.1600-065x.2007.00539.x
Subject(s) - microbiology and biotechnology , endoplasmic reticulum , biology , signal transduction , cytosol , effector , extracellular , second messenger system , receptor , intracellular , antigen , transmembrane protein , signal transducing adaptor protein , biochemistry , enzyme , immunology
Summary: B cells respond to antigen stimulation with mobilization of the Ca 2+ second messenger in two phases operated by two distinct sets of effector proteins. First, an antigen receptor‐specific Ca 2+ initiation complex is assembled, activated, and targeted to the plasma membrane to trigger the transient release of Ca 2+ from intracellular stores of the endoplasmic reticulum. Second, more ubiquitously expressed Ca 2+ channels of the plasma membrane are opened to allow for sustained Ca 2+ influx from the extracellular medium. Depending on the developmental stage of the B cell, the kinetics and profile of the two phases are adjusted at multiple levels of positive and negative regulation. A molecular basis for the Ca 2+ signaling plasticity is provided by cytosolic and transmembrane adapter proteins. They act as signal organizers, which control enzyme/substrate interactions by directing the different signaling modules into specific subcellular compartments. These arrangements orchestrate a graduated activation of Ca 2+ ‐sensitive downstream pathways, which ultimately determine appropriate cellular responses, namely elimination of autoreactive B cells or proliferation and differentiation of immunocompetent B cells into antibody‐secreting plasma cells.