LILRB2
Description
The LILRB2 (leukocyte immunoglobulin like receptor B2) is a protein-coding gene located on chromosome 19.
Leukocyte immunoglobulin-like receptor subfamily B member 2 (LILRB2) is a protein encoded by the LILRB2 gene in humans. It belongs to the leukocyte immunoglobulin-like receptor (LIR) family and is located at chromosome 19q13.4. LILRB2 features two to four extracellular immunoglobulin domains, a transmembrane domain, and two to four cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Expressed on immune cells, LILRB2 binds to MHC class I molecules on antigen-presenting cells, triggering a negative signal that inhibits immune activation. It helps regulate inflammatory responses and cytotoxicity, focusing the immune response and limiting autoimmunity. Multiple transcript variants, encoding different isoforms, have been identified for this gene. LILRB2 plays a crucial role in inhibiting axonal regeneration and functional recovery after brain injury. Recent studies show that LILRB2 acts as a β-Amyloid receptor, potentially contributing to synaptic loss and cognitive impairment in Alzheimer's disease. LILRB2 interacts with PTPN6.
LILRB2 acts as a receptor for class I MHC antigens, specifically recognizing a wide range of HLA-A, HLA-B, HLA-C, HLA-G, and HLA-F alleles. This interaction plays a crucial role in downregulating immune responses and promoting tolerance. Notably, LILRB2 recognizes HLA-G in complex with B2M/beta-2 microglobulin and a nonamer self-peptide, triggering the differentiation of type 1 regulatory T cells and myeloid-derived suppressor cells, both of which are key players in maintaining maternal-fetal tolerance. Moreover, LILRB2 competes with CD8A for binding to class I MHC antigens and inhibits FCGR1A-mediated phosphorylation of cellular proteins and mobilization of intracellular calcium ions.
LILRB2 is also known as CD85D, ILT-4, ILT4, LIR-2, LIR2, MIR-10, MIR10.
