Requirement of the cytoplasmic portion for dimer formation of Fcα/μ receptor expressed on cell surface

Cho, Yukiko; Honda, Shin‐ichiro; Yoshizawa, Yuichi; Takagaki, Kana; Usui, Kenta; Shibuya, Akira

doi:10.1016/j.molimm.2009.10.016

Cited by 8 publications

(19 citation statements)

References 16 publications

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“…A human receptor for IgM (and IgA), the Fcα/µR, closely related to the polymeric Ig receptor (plgR) in its ligand-binding domain, has also been described (41–43). Expressed predominantly on follicular dendritic cells (FDCs), the Fcα/µR is believed to function in antigen presentation and B-cell selection in the germinal centre response (35,44).…”

Section: Interference With Fcα/μ-receptorsmentioning

confidence: 99%

“…Recent work in Fcα/µR knockout mice suggest that the receptor negatively regulates T-independent antigen (common in malaria) retention by FDCs, culminating in suppression of humoral immune responses against T-independent antigens (45). The receptor can also mediate endocytosis of IgM-coated bacteria and immune-complexes (41–43). IgM binding by PfEMP1 may therefore allow infected erythrocytes to interfere with these functions of Fcα/µR.…”

Section: Interference With Fcα/μ-receptorsmentioning

confidence: 99%

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IgM, FcμRs, and Malarial Immune Evasion

Czajkowsky

Salanti

Ditlev

et al. 2010

The Journal of Immunology

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IgM is an ancestral Ab class found in all jawed vertebrates, from sharks to mammals. This ancient ancestry is shared by malaria parasites (genus Plasmodium) that infect all classes of terrestrial vertebrates with whom they coevolved. IgM, the least studied and most enigmatic of the vertebrate Igs, was recently shown to form an intimate relationship with the malaria parasite Plasmodium falciparum. In this article, we discuss how this association might have come about, building on the recently determined structure of the human IgM pentamer, and how this interaction could affect parasite survival, particularly in light of the just-discovered FcμR localized to B and T cell surfaces. Because this parasite may exploit an interaction with IgM to limit immune detection, as well as to manipulate the immune response when detected, a better understanding of this association may prove critical for the development of improved vaccines or vaccination strategies.

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Section: Interference With Fcα/μ-receptorsmentioning

confidence: 99%

Section: Interference With Fcα/μ-receptorsmentioning

confidence: 99%

IgM, FcμRs, and Malarial Immune Evasion

Czajkowsky

Salanti

Ditlev

et al. 2010

The Journal of Immunology

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“…In mice, both monomeric and dimeric Fcα/μR (approximately 65 and approximately 130 kDa, respectively) are expressed in BW5147 or Ba/F3 transfectants transfected with Fcamr cDNA. These results were not specific to the transfectants expressing Fcα/μR, because both monomeric and dimeric endogenous Fcα/μR were also detected in a B cell line, BCL1‐B20 . The immunoprecipitates of cell surface Fcα/μR protein showed only approximately 130 kDa of glycoprotein under both non‐reducing and reducing conditions, suggesting that a considerable amount of monomeric Fcα/μR is expressed in the cytoplasm.…”

Section: Molecular Characteristics Of Fcα/μrmentioning

confidence: 92%

“…Therefore, dimeric, but not monomeric, Fcα/μR is preferentially localized to the cell surface of the transfectants. In contrast to BW5147 transfectants expressing WT Fcα/μR, which shows both monomeric and dimeric formations, BW5147 cells transfected with mutated Fcamr cDNA encoding Fcα/μR lacking the cytoplasmic portion expressed only monomeric Fcα/μR protein , suggesting that the cytoplasmic portion is required for dimer formation of Fcα/μR and efficient cell surface expression of Fcα/μR. Further analyses demonstrated that the regions spanning 481–490 and 504–523 amino acids are essential for dimer formation and efficient cell surface expression of Fcα/μR, respectively ( Fig.…”

Section: Molecular Characteristics Of Fcα/μrmentioning

confidence: 95%

Immune regulation by Fcα/μ receptor (CD351) on marginal zone B cells and follicular dendritic cells

Shibuya

Honda

2015

Immunological Reviews

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Although both Fcα/μ receptor (Fcα/μR) and polymeric Ig receptor (poly-IgR) are Fc receptors for IgA and IgM and are functionally and genetically related, the expression profile of Fcα/μR is unique. Unlike poly-IgR, Fcα/μR is expressed on marginal zone (MZ) B cells and follicular dendritic cells, suggesting that Fcα/μR plays an important role in humoral immune responses. Fcα/μR mediates endocytosis of the IgM immune complex (IC). Recent research demonstrated that Fcα/μR downregulated retention of the IgM IC with a T-independent (TI) antigen on MZ B cells and follicular dendritic cells due to endocytosis of the IgM IC, suppressing germinal center formation, affinity maturation, and memory B-cell generation in response to TI antigen challenge. In addition, Fcα/μR physically associates with Toll-like receptor 4 (TLR4) and augments TLR4 oligomerization and signaling in MZ B cells upon lipopolysaccharide (LPS) challenge, leading to increased proinflammatory cytokine production by MZ B cells. Thus, Fcα/μR is a unique Fc receptor that is involved in humoral immune responses and inflammation.

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“…No tyrosines are present in the cytoplasmic domain, but a dileucine motif that is involved in receptor internalization has been described in Fcα/μR (Shibuya et al, 2000). Additionally, the cytoplasmic part is required for dimer formation, which induces cell surface expression of Fcα/μR (Cho et al, 2010).…”

Section: Fcα/μrmentioning

confidence: 99%