Leukocyte immunoglobulin-like receptors(LILRs),also called CD85s,ILTs,or LIRs,are important mediators of immune activation and tolerance that contain tandem immunoglobulin(Ig)-like folds.There are 11(in addition to tw...Leukocyte immunoglobulin-like receptors(LILRs),also called CD85s,ILTs,or LIRs,are important mediators of immune activation and tolerance that contain tandem immunoglobulin(Ig)-like folds.There are 11(in addition to two pseudogenes)LILRs in total,two with two Ig-like domains(D1D2)and the remaining nine with four Ig-like domains(D1D2D3D4).Thus far,the structural features of the D1D2 domains of LILR proteins are well defi ned,but no structures for the D3D4 domains have been reported.This is a very important fi eld to be studied as it relates to the unknown functions of the D3D4 domains,as well as their relative orientation to the D1D2 domains on the cell surface.Here,we report the crystal structures of the D3D4 domains of both LILRB1 and LILRB2.The two Ig-like domains of both LILRB1-D3D4 and LILRB2-D3D4 are arranged at an acute angle(~60°)to form a bent struc-ture,resembling the structures of natural killer inhibitory receptors.Based on these two D3D4 domain structures and previously reported D1D2/HLA I complex structures,two alternative models of full-length(four Ig-like domains)LILR molecules bound to HLA I are proposed.展开更多
Leukocyte immunoglobulin-like receptor B4(LILRB4)is an inhibitory receptor in the LILR family mainly expressed on normal and malignant human cells of myeloid origin.By binding to ligands,LILRB4 is activated and subseq...Leukocyte immunoglobulin-like receptor B4(LILRB4)is an inhibitory receptor in the LILR family mainly expressed on normal and malignant human cells of myeloid origin.By binding to ligands,LILRB4 is activated and subsequently recruits adaptors to cytoplasmic immunoreceptor tyrosine inhibitory motifs to initiate different signaling cascades,thus playing an important role in physiological and pathological conditions,including autoimmune diseases,microbial infections,and cancers.In normal myeloid cells,LILRB4 regulates intrinsic cell activation and differentiation.In disease-associated or malignant myeloid cells,LILRB4 is significantly correlated with disease severity or patient survival and suppresses T cells,thereby participating in the pathogenesis of various diseases.In summary,LILRB4 functions as an immune checkpoint on myeloid cells and may be a promising therapeutic target for various human immune diseases,especially for cancer immunotherapy.展开更多
基金the China National Grand S&T Spe-cial Project(No.2012ZX10001006)the National Natural Science Foundation of China(Grant No.31030030)GFG is a leading principal investigator of the NSFC Innovative Research Group(Grant No.81021003).
文摘Leukocyte immunoglobulin-like receptors(LILRs),also called CD85s,ILTs,or LIRs,are important mediators of immune activation and tolerance that contain tandem immunoglobulin(Ig)-like folds.There are 11(in addition to two pseudogenes)LILRs in total,two with two Ig-like domains(D1D2)and the remaining nine with four Ig-like domains(D1D2D3D4).Thus far,the structural features of the D1D2 domains of LILR proteins are well defi ned,but no structures for the D3D4 domains have been reported.This is a very important fi eld to be studied as it relates to the unknown functions of the D3D4 domains,as well as their relative orientation to the D1D2 domains on the cell surface.Here,we report the crystal structures of the D3D4 domains of both LILRB1 and LILRB2.The two Ig-like domains of both LILRB1-D3D4 and LILRB2-D3D4 are arranged at an acute angle(~60°)to form a bent struc-ture,resembling the structures of natural killer inhibitory receptors.Based on these two D3D4 domain structures and previously reported D1D2/HLA I complex structures,two alternative models of full-length(four Ig-like domains)LILR molecules bound to HLA I are proposed.
基金This work was supported by the Imported Scholar Project and Startup from Peking University Health Science Center(68263Y1056 to MD).
文摘Leukocyte immunoglobulin-like receptor B4(LILRB4)is an inhibitory receptor in the LILR family mainly expressed on normal and malignant human cells of myeloid origin.By binding to ligands,LILRB4 is activated and subsequently recruits adaptors to cytoplasmic immunoreceptor tyrosine inhibitory motifs to initiate different signaling cascades,thus playing an important role in physiological and pathological conditions,including autoimmune diseases,microbial infections,and cancers.In normal myeloid cells,LILRB4 regulates intrinsic cell activation and differentiation.In disease-associated or malignant myeloid cells,LILRB4 is significantly correlated with disease severity or patient survival and suppresses T cells,thereby participating in the pathogenesis of various diseases.In summary,LILRB4 functions as an immune checkpoint on myeloid cells and may be a promising therapeutic target for various human immune diseases,especially for cancer immunotherapy.
