Characterization of ?X I-Domain Binding to Receptors for Advanced Glycation End Products (RAGE).

ABSTRACT: The ?2 integrins are cell surface transmembrane proteins regulating leukocyte functions, such as adhesion and migration. Two members of ?2 integrin, ?M?2 and ?X?2, share the leukocyte distribution profile and integrin ?X?2 is involved in antigen presentation in dendritic cells and transendothelial migration of monocytes and macrophages to atherosclerotic lesions. Receptor for advanced glycation end products (RAGE), a member of cell adhesion molecules, plays an important role in chronic inflammation and atherosclerosis. Although RAGE and ?X?2 play an important role in inflammatory response and the pathogenesis of atherosclerosis, the nature of their interaction and structure involved in the binding remain poorly defined. In this study, using I-domain as a ligand binding motif of ?X?2, we characterize the binding nature and the interacting moieties of ?X I-domain and RAGE. Their binding requires divalent cations (Mg2+ and Mn2+) and shows an affinity on the sub-micro molar level: the dissociation constant of ?X I-domains binding to RAGE being 0.49 ?M. Furthermore, the ?X I-domains recognize the V-domain, but not the C1 and C2-domains of RAGE. The acidic amino acid substitutions on the ligand binding site of ?X I-domain significantly reduce the I-domain binding activity to soluble RAGE and the alanine substitutions of basic amino acids on the flat surface of the V-domain prevent the V-domain binding to ?X I-domain. In conclusion, the main mechanism of ?X I-domain binding to RAGE is a charge interaction, in which the acidic moieties of ?X I-domains, including E244, and D249, recognize the basic residues on the RAGE V-domain encompassing K39, K43, K44, R104, and K107.

SUBMITTER: Buyannemekh D 

PROVIDER: S-EPMC5463044 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature