LILRA3 explained

Leukocyte immunoglobulin-like receptor subfamily A member 3 (LILR-A3) also known as CD85 antigen-like family member E (CD85e), immunoglobulin-like transcript 6 (ILT-6), and leukocyte immunoglobulin-like receptor 4 (LIR-4) is a protein that in humans is encoded by the LILRA3 gene located within the leukocyte receptor complex on chromosome 19q13.4. Unlike many of its family, LILRA3 lacks a transmembrane domain. The function of LILRA3 is currently unknown; however, it is highly homologous to other LILR genes,^[1] and can bind human leukocyte antigen (HLA) class I. Therefore, if secreted, the LILRA3 might impair interactions of membrane-bound LILRs (such as LILRB1, an inhibitory receptor expressed on effector and memory CD8 T cells) with their HLA ligands, thus modulating immune reactions and influencing susceptibility to disease.^{[2] [3] [4]}

Like the closely related LILRA1, LILRA3 binds to both normal and 'unfolded' free heavy chains of HLA class I, with a preference for free heavy chains of HLA-C alleles ^[5]

See also

• Cluster of differentiation

Further reading

• Samaridis J, Colonna M . Cloning of novel immunoglobulin superfamily receptors expressed on human myeloid and lymphoid cells: structural evidence for new stimulatory and inhibitory pathways . European Journal of Immunology . 27 . 3 . 660–5 . March 1997 . 9079806 . 10.1002/eji.1830270313 . 2212182 . free .
• Cella M, Döhring C, Samaridis J, Dessing M, Brockhaus M, Lanzavecchia A, Colonna M . A novel inhibitory receptor (ILT3) expressed on monocytes, macrophages, and dendritic cells involved in antigen processing . The Journal of Experimental Medicine . 185 . 10 . 1743–51 . May 1997 . 9151699 . 2196312 . 10.1084/jem.185.10.1743 .
• Colonna M, Navarro F, Bellón T, Llano M, García P, Samaridis J, Angman L, Cella M, López-Botet M . A common inhibitory receptor for major histocompatibility complex class I molecules on human lymphoid and myelomonocytic cells . The Journal of Experimental Medicine . 186 . 11 . 1809–18 . December 1997 . 9382880 . 2199153 . 10.1084/jem.186.11.1809 .
• Wiśniewski A, Łuszczek W, Mańczak M, Jasek M, Kubicka W, Cislo M, Kuśnierczyk P . Distribution of LILRA3 (ILT6/LIR4) deletion in psoriatic patients and healthy controls . Human Immunology . 64 . 4 . 458–61 . April 2003 . 12651072 . 10.1016/S0198-8859(03)00025-9 .
• Norman PJ, Carey BS, Stephens HA, Vaughan RW . DNA sequence variation and molecular genotyping of natural killer leukocyte immunoglobulin-like receptor, LILRA3 . Immunogenetics . 55 . 3 . 165–71 . June 2003 . 12750859 . 10.1007/s00251-003-0561-1 . 52863887 .
• Zhang Z, Henzel WJ . Signal peptide prediction based on analysis of experimentally verified cleavage sites . Protein Science . 13 . 10 . 2819–24 . October 2004 . 15340161 . 2286551 . 10.1110/ps.04682504 .

Notes and References

1. Torkar M, Haude A, Milne S, Beck S, Trowsdale J, Wilson MJ . Arrangement of the ILT gene cluster: a common null allele of the ILT6 gene results from a 6.7-kbp deletion . European Journal of Immunology . 30 . 12 . 3655–62 . December 2000 . 11169408 . 10.1002/1521-4141(200012)30:12<3655::aid-immu3655>3.0.co;2-y . 38450831 .
2. Arm JP, Nwankwo C, Austen KF . Molecular identification of a novel family of human Ig superfamily members that possess immunoreceptor tyrosine-based inhibition motifs and homology to the mouse gp49B1 inhibitory receptor . Journal of Immunology . 159 . 5 . 2342–9 . September 1997 . 10.4049/jimmunol.159.5.2342 . 9278324 . 45021877 . free .
3. Borges L, Hsu ML, Fanger N, Kubin M, Cosman D . A family of human lymphoid and myeloid Ig-like receptors, some of which bind to MHC class I molecules . Journal of Immunology . 159 . 11 . 5192–6 . December 1997 . 10.4049/jimmunol.159.11.5192 . 9548455 . 36907307 . free .
4. Web site: Entrez Gene: LILRA3 leukocyte immunoglobulin-like receptor, subfamily A (without TM domain), member 3.
5. Jones DC, Kosmoliaptsis V, Apps R, Lapaque N, Smith I, Kono A, Chang C, Boyle LH, Taylor CJ, Trowsdale J, Allen RL . HLA class I allelic sequence and conformation regulate leukocyte Ig-like receptor binding . Journal of Immunology . 186 . 5 . 2990–7 . March 2011 . 21270408 . 10.4049/jimmunol.1003078 . free .