BAFF receptor (B-cell activating factor receptor, BAFF-R), also known as tumor necrosis factor receptor superfamily member 13C (TNFRSF13C) and BLyS receptor 3 (BR3), is a
membrane protein of the
TNF receptor superfamily which recognizes
BAFF, an essential factor for B cell maturation and survival.
In humans it is encoded by the ''TNFRSF13C''
gene.
Function
B-cell activating factor (BAFF) enhances B-cell survival in vitro and is a regulator of the peripheral
B-cell
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted o ...
population. The protein encoded by this gene is a receptor for BAFF and is a type III
transmembrane protein containing a single extracellular
phenylalanine
Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino a ...
-rich domain. It is thought that this receptor is the principal receptor required for BAFF-mediated mature B-cell survival.
In B cell maturation, due to regulation by BAFF-R, only a limited amount of B-cell will survive.
Clinical significance
Overexpression of BAFF in mice results in mature B-cell
hyperplasia
Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferati ...
and symptoms of
systemic lupus erythematosus
Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...
(SLE). Also, some SLE patients have increased levels of BAFF in serum. Therefore, it has been proposed that abnormally high levels of BAFF may contribute to the pathogenesis of autoimmune diseases by enhancing the survival of autoreactive B cells, which are cells that show immune response to normal body cells.
Autoreactive B cells are less sensitive toward BAFF and are usually outcompeted by the normal B cells in the maturation process regulated by low BAFF-R expression. An elevated level of BAFF-R can therefore overcome this decreased response and result in accumulation of autoreactive B cells.
BAFF and BAFF-R pair can also down-regulate the cell
apoptosis
Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...
process.
See also
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B-cell activating factor
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B-cell maturation antigen
B-cell maturation antigen (BCMA or BCM), also known as tumor necrosis factor receptor superfamily member 17 (TNFRSF17), is a protein that in humans is encoded by the TNFRSF17 gene.
TNFRSF17 is a cell surface receptor of the TNF receptor superfam ...
References
External links
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Further reading
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Clusters of differentiation
TNF receptor family
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