FCRL5
Domain
Contains 2 copies of a cytoplasmic motif that is referred to as the immunoreceptor tyrosine-based inhibitor motif (ITIM).
Function
Plays an important role in B-cell response to antigen that acts both as a negative or positive coreceptor. Inhibits B-cell receptor (BCR) signaling in the absence of CR2 stimulation but engagement with CR2 and the BCR lead to a superior calcium response compared to CR2 and BCR costimulation (PubMed:30107486). May be involved in B-cell development and differentiation in peripheral lymphoid organs and may be useful markers of B-cell stages. May have an immunoregulatory role in marginal zone B-cells. May play a role in fertilization (By similarity).
Involvement in disease
A chromosomal aberration involving FCRL5 has been found in cell lines with 1q21 abnormalities derived from Burkitt lymphoma. Duplication dup(1)(q21q32).
Tissue Specificity
Expressed in marginal zone B-cells, immunoblasts, tonsillar germinal center centrocytes and in the intraepithelial and interfollicular regions of the tonsil. Expressed in many lymphoma cell lines and on hairy cell leukemia cells. Isoform 1, isoform 3, isoform 4 and isoform 5 are detected in lymph node, spleen, bone marrow, and small intestine with preponderance of isoform 3. Expressed in mature and memory B-cells and down-regulated in germinal center cells (at protein level).
Cellular localization
- Cell membrane
- Single-pass type I membrane protein
Alternative names
CD307e, FCRH5, IRTA2, UNQ503/PRO820, FCRL5, Fc receptor-like protein 5, FcR-like protein 5, FcRL5, BXMAS1, Fc receptor homolog 5, Immune receptor translocation-associated protein 2, FcRH5