Biomaterial Database

Interaction of signaling molecules with human Fc gamma RIIb1 and the role of various Fc gamma RIIb isoforms in B-cell regulation. 1995

G Sarmay, and Z Rozsnyay, and G Koncz, and J Gergely

Laboratory of Immunoregulation, Vienna International Research Cooperation Center, Sandoz Forschungsinstitut, Austria.

The low-affinity type-IIb IgG Fc-binding receptors (Fc gamma RIIb) are expressed on B cells. When cross-linked with mIgM Fc gamma RIIb are known to down-regulate B-cell activation by interrupting signal transduction upstream from G-protein-activated events. We have studied Fc gamma RII isoforms expressed on resting and activated B cells and the interaction of Fc gamma RIIb1 with molecules transducing the antigen receptor-mediated signals. Expression of Fc gamma RII isoforms was studied by reverse transcription and polymerase chain reaction. Resting B cells express both Fc gamma RIIb2 and Fc gamma RIIb1 isoforms. Activation with anti-IgM or IL-4 induces the splicing of Fc gamma RIIb1 mRNA, while the alternative splicing of Fc gamma RIIb2 mRNA is down-regulated, resulting in the surface expression of Fc gamma RIIb1. Functional differences were found between the two isoforms in inhibiting B-cell activation, suggesting that Fc gamma RIIb2 might influence the threshold of signals necessary for activation of resting B cells, while Fc gamma RIIb1 may regulate in later phases of antibody response. To explore the mechanism by which Fc gamma RII may uncouple antigen receptor-mediated signal transduction, we have investigated the association of signaling molecules with Fc gamma RII. Beside the protein tyrosine kinase (PTK) fyn, protein kinase C (PKC) was found to be co-isolated with Fc gamma RIIb1, suggesting a tight connection between these kinases and Fc gamma RII. We suggest that PKC might be responsible for the activation-induced phosphorylation of Fc gamma RII on serine residues.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008213	Lymphocyte Activation	Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.	Blast Transformation,Blastogenesis,Lymphoblast Transformation,Lymphocyte Stimulation,Lymphocyte Transformation,Transformation, Blast,Transformation, Lymphoblast,Transformation, Lymphocyte,Activation, Lymphocyte,Stimulation, Lymphocyte
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D011233	Precipitin Tests	Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.	Precipitin Test,Test, Precipitin,Tests, Precipitin
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011493	Protein Kinase C	An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.	Calcium Phospholipid-Dependent Protein Kinase,Calcium-Activated Phospholipid-Dependent Kinase,PKC Serine-Threonine Kinase,Phospholipid-Sensitive Calcium-Dependent Protein Kinase,Protein Kinase M,Calcium Activated Phospholipid Dependent Kinase,Calcium Phospholipid Dependent Protein Kinase,PKC Serine Threonine Kinase,Phospholipid Sensitive Calcium Dependent Protein Kinase,Phospholipid-Dependent Kinase, Calcium-Activated,Serine-Threonine Kinase, PKC
D011505	Protein-Tyrosine Kinases	Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.	Tyrosine Protein Kinase,Tyrosine-Specific Protein Kinase,Protein-Tyrosine Kinase,Tyrosine Kinase,Tyrosine Protein Kinases,Tyrosine-Specific Protein Kinases,Tyrosylprotein Kinase,Kinase, Protein-Tyrosine,Kinase, Tyrosine,Kinase, Tyrosine Protein,Kinase, Tyrosine-Specific Protein,Kinase, Tyrosylprotein,Kinases, Protein-Tyrosine,Kinases, Tyrosine Protein,Kinases, Tyrosine-Specific Protein,Protein Kinase, Tyrosine-Specific,Protein Kinases, Tyrosine,Protein Kinases, Tyrosine-Specific,Protein Tyrosine Kinase,Protein Tyrosine Kinases,Tyrosine Specific Protein Kinase,Tyrosine Specific Protein Kinases
D011518	Proto-Oncogene Proteins	Products of proto-oncogenes. Normally they do not have oncogenic or transforming properties, but are involved in the regulation or differentiation of cell growth. They often have protein kinase activity.	Cellular Proto-Oncogene Proteins,c-onc Proteins,Proto Oncogene Proteins, Cellular,Proto-Oncogene Products, Cellular,Cellular Proto Oncogene Proteins,Cellular Proto-Oncogene Products,Proto Oncogene Products, Cellular,Proto Oncogene Proteins,Proto-Oncogene Proteins, Cellular,c onc Proteins
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001402	B-Lymphocytes	Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.	B-Cells, Lymphocyte,B-Lymphocyte,Bursa-Dependent Lymphocytes,B Cells, Lymphocyte,B Lymphocyte,B Lymphocytes,B-Cell, Lymphocyte,Bursa Dependent Lymphocytes,Bursa-Dependent Lymphocyte,Lymphocyte B-Cell,Lymphocyte B-Cells,Lymphocyte, Bursa-Dependent,Lymphocytes, Bursa-Dependent
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA