FCRL3

From Wikipedia, the free encyclopedia
FCRL3
Identifiers
AliasesFCRL3, CD307c, FCRH3, IFGP3, IRTA3, SPAP2, Fc receptor like 3
External IDsOMIM: 606510 HomoloGene: 76447 GeneCards: FCRL3
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001024667
NM_052939
NM_001320333

n/a

RefSeq (protein)

NP_001307262
NP_443171

n/a

Location (UCSC)Chr 1: 157.67 – 157.7 Mbn/a
PubMed search[2]n/a
Wikidata
View/Edit Human

Fc receptor-like protein 3 is a protein that in humans is encoded by the FCRL3 gene.[3][4][5]

This gene encodes a member of the immunoglobulin receptor superfamily and is one of several Fc receptor-like glycoproteins clustered on the long arm of chromosome 1. The encoded protein contains immunoreceptor-tyrosine activation motif (ITAM) and immunoreceptor-tyrosine inhibitory motif (ITIM) in its cytoplasmic domain and may play a role in regulation of the immune system. Mutations in this gene have been associated with rheumatoid arthritis, autoimmune thyroid disease, and systemic lupus erythematosus.[5]

Structure[]

Fc receptor-like protein 3 is a type I transmembrane glycoprotein, which consists of an extracellular region, a transmembrane domain and a cytoplasmatic tail. The extracellular region consists of five immunoglobulin-like domains, which share varying degree of homology to extracellular domains of other Fc receptor-like protein family members, as well as extracellular domains of Fc receptors FcγRI, FcγRII and FcγRIII.[3][6][7]

The transmembrane region consists of hydrophobic residues and is uncharged.[6][7]

The cytoplasmatic region contains two signalling motifs, a membrane-proximal  ITAM and a carboxy-proximal ITAM-like motif. The presence of both an activating and inhibitory motifs suggests potential dual-signalling properties.[3][6][7]

Signalling[]

Fc receptor-like protein 3 has a role in regulation in both innate and adaptive signalling pathways in association with other signalling molecules. It contains both an activation (ITAM-like) and an inhibitory (ITIM) motif in its cytoplasmic region, pointing to its dual-regulatory potential. FCRL3 is capable of associating with intracellular signalling molecules including Syk, Zap-70, SHP-1, and SHP-2.[6][8]

Activation properties of FCRL3 were observed in relation to TLR9-mediated signalling. FCRL3 engagement with receptor-specific monoclonal antibodies (mAbs) augmented TLR9-mediated blood B cell survival, proliferation and activation.  It led to improved expression of activation markers CD25, CD86 and HLA-DR on cell surface via CpG-mediated NFκB and MAPK pathways activation. Expression of CD54 and CD80 was not significantly altered by this ligation. CpG signalling could potentially enhance differentiation of B cells into Ig-secreting plasma cells. But, FCRL3 ligation with mAbs halted differentiation of antibody secreting plasma B cells by inhibiting B-lymphocyte-induced maturation protein 1 (BLIMP1) expression via Erk signalling pathway.[7][8]

Inhibitory role of FCRL3 has been described in its negative regulation of B-cell receptor (BCR) signalling. Co-ligation of FCRL3 with BCR facilitates SHP-1 and SHP-2 recruitment via its intracellular ITIM motif. This leads to inhibition of Syk kinase and PLCγ2 phopshorylation, which suppresses downstream calcium signalling and apoptosis.[6][7][8]

FCRL3 has no known ligands.[6][7][8]

Expression[]

Fc receptor-like protein 3 is preferentially expressed on B cell, and is along the FCRL6 the only gene from this family which is expressed also outside B-cell lineage, as it has been detected also on NK cell and T cell subsets. The rest of the Fc receptor-like family are considered B cell markers.[6][7][8]

It is expressed in relatively low levels on naïve B cells, germinal center B cells, memory B cells, marginal zone B cells and peripheral blood and tonsil B-cells, and at slightly higher levels on splenic naïve and memory B cells. Its expression was not detected on pro-B cells, pre-B cells and bone marrow-derived plasmatic B cells.[7][8]

Highest levels of FCRL3 expression were detected on circulating memory B cells, as well as innate-like marginal zone B cells. Memory B cell subsets with innate-like properties have also been observed to have higher FCRL3 expression, which had a potent co-stimmulatory effect on TLR9-mediated B cell activation, as well as activation and inhibitory effect on plasma cell differentiation.[7][8]

Outside B cell lineage, FCLR3 expression has been detected on CD56+ natural killer cells, CD4+ and CD8+ T cells, as well as regulatory CD4+FOXP3+ T cells. Notably, it has also been observed on a subpopulation of natural Treg (nTreg) cells with high expression levels of PD-1, which had impaired IL-2 responsiveness, and also on Helios Treg cells, where it was co-expressed with T-cell immunoreceptor with Ig and ITIM domains (TIGIT).[6][7][8]

Function[]

Given its dual-signalling properties, FCRL3 mediates BCR signalling as well as plasma B cell maturation and antibody production.[7][8]

FCRL3 has been shown to interact with PTPN6.[9]

Potential role in disease[]

The FCRL3 loci is associated with numerous autoimmune diseases. Single-nucleotide polymorphism (SNP) -169 C/T located in promoter region of FCRL3 has been linked to higher susceptibility to diseases including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and . This polymorphism enhanced expression levels of FCRL3 via more efficient NFκB binding and increased promoted activity.[6][7][8][10]

Elevated expression levels of FCRL3 on Treg cells, cytotoxic CD8+ T cells and γδ-T cells are associated with rheumatoid arthritis.[7]

FCRL3 gene polymorphism is also associated with multiple sclerosis, autoimmune pancreatitis, type I diabetes and Bahcet’s disease in various populations.[7]

Thymus derived FCRL3+ Treg were observed to have higher PD-1 expression and lower responsiveness to antigenic stimulation, as well as reduced suppression properties on effector T cell proliferation. FCRL3 expression on Treg cells is also associated with -169 C/T SNP in FCRL3 promoter region. Overall, FCRL3 expression on Treg cells leads to dysfunction in regulation of self-tolerance and increases susceptibility to autoimmunity.[6][7][10]

FCRL3 is considered an autoimmunity marker.[7][10]

References[]

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000160856 - Ensembl, May 2017
  2. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  3. ^ a b c Davis RS, Wang YH, Kubagawa H, Cooper MD (August 2001). "Identification of a family of Fc receptor homologs with preferential B cell expression". Proceedings of the National Academy of Sciences of the United States of America. 98 (17): 9772–7. Bibcode:2001PNAS...98.9772D. doi:10.1073/pnas.171308498. PMC 55528. PMID 11493702.
  4. ^ Davis RS, Dennis G Jr, Kubagawa H, Cooper MD (May 2002). "Fc receptor homologs (FcRH1-5) extend the Fc receptor family". The Interface Between Innate and Acquired Immunity. Curr Top Microbiol Immunol. Current Topics in Microbiology and Immunology. Vol. 266. pp. 85–112. doi:10.1007/978-3-662-04700-2_7. ISBN 978-3-642-07682-4. PMID 12014205.
  5. ^ a b "Entrez Gene: FCRL3 Fc receptor-like 3".
  6. ^ a b c d e f g h i j Davis RS (April 2007). "Fc receptor-like molecules". Annual Review of Immunology. 25 (1): 525–60. doi:10.1146/annurev.immunol.25.022106.141541. PMID 17201682.
  7. ^ a b c d e f g h i j k l m n o p Rostamzadeh D, Kazemi T, Amirghofran Z, Shabani M (June 2018). "Update on Fc receptor-like (FCRL) family: new immunoregulatory players in health and diseases". Expert Opinion on Therapeutic Targets. 22 (6): 487–502. doi:10.1080/14728222.2018.1472768. PMID 29737217. S2CID 13659120.
  8. ^ a b c d e f g h i j Li, F. J.; Won, W. J.; Becker, E. J.; Easlick, J. L.; Tabengwa, E. M.; Li, R.; Shakhmatov, M.; Honjo, K.; Burrows, P. D. (2014), Daeron, Marc; Nimmerjahn, Falk (eds.), "Emerging Roles for the FCRL Family Members in Lymphocyte Biology and Disease", Fc Receptors, Cham: Springer International Publishing, vol. 382, pp. 29–50, doi:10.1007/978-3-319-07911-0_2, ISBN 978-3-319-07910-3, PMC 4242170, PMID 25116094
  9. ^ Xu MJ, Zhao R, Cao H, Zhao ZJ (May 2002). "SPAP2, an Ig family receptor containing both ITIMs and ITAMs". Biochemical and Biophysical Research Communications. 293 (3): 1037–46. doi:10.1016/S0006-291X(02)00332-7. PMID 12051764.
  10. ^ a b c Chistiakov DA, Chistiakov AP (May 2007). "Is FCRL3 a new general autoimmunity gene?". Human Immunology. 68 (5): 375–83. doi:10.1016/j.humimm.2007.01.013. PMID 17462505.

Further reading[]

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