Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
The Journal of Experimental Medicine
Year: 2009  |  Volume: 206  |  Issue: 12  |  Page No.: 2779 - 2793

Identity of the elusive IgM Fc receptor (Fc{micro}R) in humans

H Kubagawa, S Oka, Y Kubagawa, I Torii, E Takayama, D. W Kang, G. L Gartland, L. F Bertoli, H Mori, H Takatsu, T Kitamura, H Ohno and J. Y. Wang    

Abstract:

Although Fc receptors (FcRs) for switched immunoglobulin (Ig) isotypes have been extensively characterized, FcR for IgM (FcµR) has defied identification. By retroviral expression and functional cloning, we have identified a complementary DNA (cDNA) encoding a bona fide FcµR in human B-lineage cDNA libraries. FcµR is defined as a transmembrane sialoglycoprotein of ~60 kD, which contains an extracellular Ig-like domain homologous to two other IgM-binding receptors (polymeric Ig receptor and Fc/µR) but exhibits an exclusive Fcµ-binding specificity. The cytoplasmic tail of FcµR contains conserved Ser and Tyr residues, but none of the Tyr residues match the immunoreceptor tyrosine-based activation, inhibitory, or switch motifs. Unlike other FcRs, the major cell types expressing FcµR are adaptive immune cells, including B and T lymphocytes. After antigen-receptor ligation or phorbol myristate acetate stimulation, FcµR expression was up-regulated on B cells but was down-modulated on T cells, suggesting differential regulation of FcµR expression during B and T cell activation. Although this receptor was initially designated as Fas apoptotic inhibitory molecule 3, or TOSO, our results indicate that FcµR per se has no inhibitory activity in Fas-mediated apoptosis and that such inhibition is only achieved when anti-Fas antibody of an IgM but not IgG isotype is used for inducing apoptosis.

View Fulltext    |   Related Articles   |   Back
   
 
 
 
  Related Articles

No Article Found
 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility