2d3v: Difference between revisions

Revision as of 17:55, 21 February 2008

Crystal Structure of Leukocyte Ig-like Receptor A5 (LILRA5/LIR9/ILT11)

OverviewOverview

Human leukocyte Ig-like receptor B1 (LILRB1) and B2 (LILRB2) belong to "Group 1" receptors and recognize a broad range of major histocompatibility complex class I molecules (MHCIs). In contrast, "Group 2" receptors show low similarity with LILRB1/B2, and their ligands remain to be identified. To date, the structural and functional characteristics of Group 2 LILRs are poorly understood. Here we report the crystal structure of the extracellular domain of LILRA5, which is an activating Group 2 LILR expressed on monocytes and neutrophils. Unexpectedly, the structure showed large changes in structural conformation and charge distribution in the region corresponding to the MHCI binding site of LILRB1/B2, which are also distinct from killer cell Ig-like receptors and Fc alpha receptors. These changes probably confer the structural hindrance for the MHCI binding, and their key amino acid substitutions are well conserved in Group 2 LILRs. Consistently, the surface plasmon resonance and flow cytometric analyses demonstrated that LILRA5 exhibited no affinities to all tested MHCIs. These results raised the possibility that LILRA5 as well as Group 2 LILRs do not play a role in any MHCI recognition but could possibly bind to non-MHCI ligand(s) on the target cells to provide a novel immune regulation mechanism.

About this StructureAbout this Structure

2D3V is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

ReferenceReference

Crystal structure of the human monocyte-activating receptor, "Group 2" leukocyte Ig-like receptor A5 (LILRA5/LIR9/ILT11)., Shiroishi M, Kajikawa M, Kuroki K, Ose T, Kohda D, Maenaka K, J Biol Chem. 2006 Jul 14;281(28):19536-44. Epub 2006 May 3. PMID:16675463

Page seeded by OCA on Thu Feb 21 16:55:07 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
-[[Image:2d3v.gif|left|200px]]<br />
+[[Image:2d3v.gif|left|200px]]<br /><applet load="2d3v" size="350" color="white" frame="true" align="right" spinBox="true"
-<applet load="2d3v" size="450" color="white" frame="true" align="right" spinBox="true"
 caption="2d3v, resolution 1.85&Aring;" />
 '''Crystal Structure of Leukocyte Ig-like Receptor A5 (LILRA5/LIR9/ILT11)'''<br />
 ==Overview==
-Human leukocyte Ig-like receptor B1 (LILRB1) and B2 (LILRB2) belong to, "Group 1" receptors and recognize a broad range of major, histocompatibility complex class I molecules (MHCIs). In contrast, "Group, 2" receptors show low similarity with LILRB1/B2, and their ligands remain, to be identified. To date, the structural and functional characteristics, of Group 2 LILRs are poorly understood. Here we report the crystal, structure of the extracellular domain of LILRA5, which is an activating, Group 2 LILR expressed on monocytes and neutrophils. Unexpectedly, the, structure showed large changes in structural conformation and charge, distribution in the region corresponding to the MHCI binding site of, LILRB1/B2, which are also distinct from killer cell Ig-like receptors and, Fc alpha receptors. These changes probably confer the structural hindrance, for the MHCI binding, and their key amino acid substitutions are well, conserved in Group 2 LILRs. Consistently, the surface plasmon resonance, and flow cytometric analyses demonstrated that LILRA5 exhibited no, affinities to all tested MHCIs. These results raised the possibility that, LILRA5 as well as Group 2 LILRs do not play a role in any MHCI recognition, but could possibly bind to non-MHCI ligand(s) on the target cells to, provide a novel immune regulation mechanism.
+Human leukocyte Ig-like receptor B1 (LILRB1) and B2 (LILRB2) belong to "Group 1" receptors and recognize a broad range of major histocompatibility complex class I molecules (MHCIs). In contrast, "Group 2" receptors show low similarity with LILRB1/B2, and their ligands remain to be identified. To date, the structural and functional characteristics of Group 2 LILRs are poorly understood. Here we report the crystal structure of the extracellular domain of LILRA5, which is an activating Group 2 LILR expressed on monocytes and neutrophils. Unexpectedly, the structure showed large changes in structural conformation and charge distribution in the region corresponding to the MHCI binding site of LILRB1/B2, which are also distinct from killer cell Ig-like receptors and Fc alpha receptors. These changes probably confer the structural hindrance for the MHCI binding, and their key amino acid substitutions are well conserved in Group 2 LILRs. Consistently, the surface plasmon resonance and flow cytometric analyses demonstrated that LILRA5 exhibited no affinities to all tested MHCIs. These results raised the possibility that LILRA5 as well as Group 2 LILRs do not play a role in any MHCI recognition but could possibly bind to non-MHCI ligand(s) on the target cells to provide a novel immune regulation mechanism.
 ==About this Structure==
-D3V is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2D3V OCA].
+D3V is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2D3V OCA].
 ==Reference==
@@ Line 22: / Line 21: @@
 [[Category: immunoglobulin-like fold]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 12 21:25:57 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:55:07 2008''