Fc receptor-like A (FCRLA)

Fc receptor-like A (FCRLA) is an intracellular, endoplasmic reticulum-resident protein selectively expressed in B lineage cells, especially at varying levels across stages of B cell differentiation and more abundantly in germinal center B cells[1][2][4]. Unlike classical Fc receptors—which are transmembrane molecules mediating antibody-dependent cellular responses—FCRLA lacks a transmembrane domain or N-linked glycosylation sites, remaining soluble within the ER lumen[1][2]. FCRLA is unique among Fc receptor-like proteins in its ability to associate intracellularly with multiple immunoglobulin isotypes (IgM, IgG, IgA), suggesting a potential chaperone-like function in antibody assembly or regulation[1][5]. While its precise physiological role is still unclear, FCRLA is implicated in B cell differentiation, possibly functioning as an ER-localized regulator of immunoglobulin processing or trafficking[1][4][5]. Elevated FCRLA expression has been observed in certain forms of B cell lymphoma, such as chronic lymphocytic leukemia (CLL), indicating a potential role as a diagnostic biomarker[2][4]. FCRLA is not considered a classical therapeutic target as it is not a transmembrane or surface-accessible receptor and currently has no known interacting drugs or therapeutic mechanisms directly targeting it.

Other names

Fc receptor-like AFCRLAFCRLFCRL1FCRLM1FCRXFREBFcRXMGC4595FCRLc2FCRLbFCRLc1FCRLdFCRLeFc receptor homolog expressed in B-cellsFc receptor-like and mucin-like protein 1Fc receptor-like proteinFc receptor-related protein XFCRLXFc receptor homolog expressed in B cells (FREB)Fc receptor-like and mucin-like 1