PMID: 12768205

 

    Legend: Gene, Sites

Title : Insights into IgA-mediated immune responses from the crystal structures of human FcalphaRI and its complex with IgA1-Fc

Abstract :

1. Immunoglobulin-alpha ( IgA )-bound antigens induce immune effector responses by activating the IgA-specific receptor FcalphaRI ( CD89 ) on immune cells
2. Here we present crystal structures of human FcalphaRI alone and in a complex with the Fc region of IgA1 (Fcalpha) Fcalpha )
3. FcalphaRI has two immunoglobulin-like domains that are oriented at approximately right angles to each other
4. Fcalpha resembles the Fcs of immunoglobulins IgG and IgE , but has differently located inter chain disulphide bonds and external rather than interdomain N-linked carbohydrates
5. Unlike 1:1 FcgammaRIII:Ig G and Fc epsilon RI : IgE complexes, two FcalphaRI molecules bind each Fcalpha dimer , one at each Calpha2-Calpha3 junction
6. The FcalphaRI-binding site on IgA1 overlaps the reported polymeric immunoglobulin receptor ( pIgR )-binding site , which might explain why secretory IgA cannot initiate phagocytosis or bind to FcalphaRI-expressing cells in the absence of an integrin co-receptor

Output (sent_index, trigger, protein, sugar, site):

• 4. has, , Fcalpha, interdomain N-linked carbohydrates, -

Output(Part-Of) (sent_index, protein, site):

• 2. IgA1 (Fcalpha), region
• 3. FcalphaRI, domains
• 6. FcalphaRI, site
• 6. IgA1, site

*Output_Site_Fusion* (sent_index, protein, sugar, site):

 

Protein	NCBI ID	SENTENCE INDEX
CD89	2204	1
IgA1	3493	0,6
IgA1 (Fcalpha)	3493	2
FcalphaRI	2204	0,1,2,3,5,6
Fc epsilon RI	2205	5