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TRIM 21: a cytosolic Fc receptor with broad antibody isotype specificity
Author(s) -
Foss Stian,
Watkinson Ruth,
Sandlie Inger,
James Leo C.,
Andersen Jan Terje
Publication year - 2015
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/imr.12363
Subject(s) - antibody , biology , cytosol , trim , isotype , receptor , extracellular , humoral immunity , microbiology and biotechnology , immunology , virology , biochemistry , monoclonal antibody , enzyme , computer science , operating system
Summary Antibodies are key molecules in the fight against infections. Although previously thought to mediate protection solely in the extracellular environment, recent research has revealed that antibody‐mediated protection extends to the cytosolic compartment of cells. This postentry viral defense mechanism requires binding of the antibody to a cytosolic Fc receptor named tripartite motif containing 21 ( TRIM 21). In contrast to other Fc receptors, TRIM 21 shows remarkably broad isotype specificity as it does not only bind IgG but also IgM and IgA. When viral pathogens coated with these antibody isotypes enter the cytosol, TRIM 21 is rapidly recruited and efficient neutralization occurs before the virus has had the time to replicate. In addition, inflammatory signaling is induced. As such, TRIM 21 acts as a cytosolic sensor that engages antibodies that have failed to protect against infection in the extracellular environment. Here, we summarize our current understanding of how TRIM 21 orchestrates humoral immunity in the cytosolic environment.