Molecular characterization of the dimer formation of Fcα/μ receptor (CD351)

• Published in: Molecular immunology Vol. 56; no. 1-2; pp. 23 - 27
• Main Authors: Takagaki, Kana, Satoh, Kazuki, Honda, Shin-ichiro, Shibuya, Akira
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2013; Elsevier
• Subjects: Amino Acid Sequence; amino acids; Animals; beta-mercaptoethanol; Blotting, Western; boiling; Cell Line, Tumor; Dimer formation; Fc receptor; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; IgA; IgM; immunoblotting; immunoglobulin A; immunoglobulin M; Mice; Molecular Sequence Data; molecular weight; mutants; Mutation; Protein Binding; Protein Multimerization; Receptors, Fc - chemistry; Receptors, Fc - genetics; Receptors, Fc - metabolism; Sequence Homology, Amino Acid; Transfection; IgA; Fc receptor; Dimer formation; IgM
• ISSN: 0161-5890; 1872-9142; 1872-9142
• DOI: 10.1016/j.molimm.2013.04.003

Fcα/μR (CD351) is an Fc receptor for both IgA and IgM and forms an atypical dimer that is resistant to reduction by 2-mercaptoethanol or boiling. We previously demonstrated that the cytoplasmic portion of Fcα/μR is required for dimer formation and for its efficient cell-surface expression. However, the biochemical nature of these phenomena has not been determined. By using a BW5147 mouse cell line expressing deletion mutants of the cytoplasmic region of Fcα/μR, we found that the region spanning amino acids 504–523 was required for efficient cell-surface expression, whereas the region spanning amino acids 481–490 was required for dimmer formation. Immunoblotting analyses of transfectants simultaneously expressing Flag-tagged Fcα/μR and hemagglutinin-tagged Fcα/μR suggested that Fcα/μR does not form homodimers. Instead, our data suggest that Fcα/μR forms heterodimers with an as-yet-unknown molecule with a molecular weight of 60–70kDa.