Fcα/μ receptor (Fcα/μR / FCAMR) is a Fc receptor for IgA and IgM. The gene of Fcα/μR / FCAMR is closely located at the polymeric immunoglobulin receptor (poly-IgR) in the Fc receptor gene cluster on the chromosome 1. The Fcα/μR / FCAMR gene containing the entire coding regions was found in the locus from the 194644 to 194653 kbp on chromosome1(GenBank and DDBJ accession number: NT004787) and is a single gene-family member with 6 extons. Fcα/μR / FCAMR transcripts is expressed in a variety of hematopoietic and non- hematopoietic tissues including thymus, spleen, liver, kidney, small and large intestines, and placenta. Fcα/μR / FCAMR have a conserved motif in the Ig-like domain, which binds to the Fc of IgA and IgM.
Fcα/μR / FCAMR mediates endocytosis of IgM-coated microbial pathogens. Fcα/μR / FCAMR is also involved in protection against microbial infection by stimulating phagocytosis, as well as in antigen processing and presentation to helper T cells, resulting in linkage from innate to adaptive immune responses.