CD22 attenuates calcium signaling by potentiating plasma membrane calcium-ATPase activity.
Nat Immunol
; 5(6): 651-7, 2004 Jun.
Article
em En
| MEDLINE
| ID: mdl-15133509
ABSTRACT
Binding of antigen to the B cell receptor induces a calcium response, which is required for proliferation and antibody production. CD22, a B cell surface protein, inhibits this signal through mechanisms that have been obscure. We report here that CD22 augments calcium efflux after B cell receptor crosslinking. Inhibition of plasma membrane calcium-ATPase (PMCA) attenuated these effects, as did disruption by homologous recombination of the gene encoding PMCA4a and PMCA4b. PMCA coimmunoprecipitated with CD22 in an activation-dependent way. CD22 cytoplasmic tyrosine residues were required for association with PMCA and enhancement of calcium efflux. Moreover, CD22 regulation of efflux and the calcium response required the tyrosine phosphatase SHP-1. Thus, SHP-1 and PMCA provide a mechanism by which CD22, a tissue-specific negative regulator, can affect calcium responses.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Antígenos de Diferenciação de Linfócitos B
/
Antígenos CD
/
Moléculas de Adesão Celular
/
Membrana Celular
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ATPases Transportadoras de Cálcio
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Sinalização do Cálcio
/
Lectinas
Limite:
Animals
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article