Cytoplasmic domain heterogeneity and functions of IgG Fc receptors in B lymphocytes.
B lymphocytes and macrophages express closely related immunoglobulin G (IgG) Fc receptors (Fc gamma RII) that differ only in the structures of their cytoplasmic domains. Because of cell type-specific alternative messenger RNA splicing, B-cell Fc gamma RII contains an insertion of 47 amino acids that participates in determining receptor function in these cells. Transfection of an Fc gamma RII-negative B-cell line with complementary DNA's encoding the two splice products and various receptor mutants indicated that the insertion was responsible for preventing both Fc gamma RII-mediated endocytosis and Fc gamma RII-mediated antigen presentation. The insertion was not required for Fc gamma RII to modulate surface immunoglobulin-triggered B-cell activation. Instead, regulation of activation involved a region of the cytoplasmic domain common to both the lymphocyte and macrophage receptor isoforms. In contrast, the insertion did contribute to the formation of caps in response to receptor cross-linking, consistent with suggestions that the lymphocyte but not macrophage form of the receptor can associate with the detergent-insoluble cytoskeleton.
Amigorena
S
S
Laboratoire d'Immunologie Cellulaire et Clinique, INSERM U 255, Institut Curie, Paris, France.
Bonnerot
C
C
Drake
J R
JR
Choquet
D
D
Hunziker
W
W
Guillet
J G
JG
Webster
P
P
Sautes
C
C
Mellman
I
I
Fridman
W H
WH
D000595:Amino Acid Sequence; D000936:Antigen-Antibody Complex / Q000378:metabolism; D000937:Antigen-Antibody Reactions / Q000235:genetics / Q000276:immunology; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D000943:Antigens, Differentiation / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D004268:DNA-Binding Proteins; D004306:Dose-Response Relationship, Immunologic; D004705:Endocytosis / Q000235:genetics / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D008213:Lymphocyte Activation / Q000276:immunology; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D011961:Receptors, Fc / Q000235:genetics / Q000276:immunology*; D017452:Receptors, IgG; D012097:Repressor Proteins / Q000494:pharmacology; D014157:Transcription Factors / Q000494:pharmacology; D014162:Transfection; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
D000936:Antigen-Antibody Complex; D015703:Antigens, CD; D000943:Antigens, Differentiation; D004268:DNA-Binding Proteins; D011961:Receptors, Fc; D017452:Receptors, IgG; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D002118:Calcium