title: Role of ICAM-1 polymorphisms (G241R, K469E) in mediating its single-molecule binding ability: atomic force microscopy measurements on living cells.
abstract: Atherosclerosis (As) is characterized by chronic inflammation and is a major cause of human mortality. ICAM-1-mediated adhesion of leukocytes in vessel walls plays an important role in the pathogenesis of atherosclerosis. Two single nucleotide polymorphisms (SNPs) of human intercellular adhesion molecule-1 (ICAM-1), G241R and K469E, are associated with a number of inflammatory diseases. SNP induced changes in ICAM-1 function rely not only on the expression level but also on the single-molecule binding ability which may be affected by single molecule conformation variations such as protein splicing and folding. Previous studies have shown associations between G241R/K469E polymorphisms and ICAM-1 gene expression. Nevertheless, few studies have been done that focus on the single-molecule forces of the above SNPs and their ligands. In the current study, we evaluated both single molecule binding ability and expression level of 4 ICAM-1 mutations - GK (G241/K469), GE (G241/E469), RK (R241/K469) and RE (R241/E469). No difference in adhesion ability was observed via cell adhesion assay or atomic force microscopy (AFM) measurement when comparing the GK, GE, RK, or RE genotypes of ICAM-1 to each other. On the other hand, flow cytometry suggested that there was significantly higher expression of GE genotype of ICAM-1 on transfected CHO cells. Thus, we concluded that genetic susceptibility to diseases related to ICAM-1 polymorphisms, G241R or K469E, might be due to the different expressions of ICAM-1 variants rather than to the single-molecule binding ability of ICAM-1.
authors.affiliation: Chinese (301) General Hospital, 28 Fuxing Road, Haidian District, Beijing 100853, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Bai
authors.affiliation: Beijing Institute of Biotechnology, 20 Dongdajie, Fengtai, Beijing 100071, China.
authors.forename: Shaoqiong
authors.initials: S
authors.lastname: Yi
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry Chinese Academy of Sciences, 2 Zhongguancun North 1st Street, Beijing 100190, China.
authors.forename: Xuejie
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, The General Hospital of Chinese People's Armed Police Forces, Beijing 100039, China. Electronic address: lhl518@vip.sina.com.
authors.forename: Huiliang
authors.initials: H
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry Chinese Academy of Sciences, 2 Zhongguancun North 1st Street, Beijing 100190, China. Electronic address: xfang@iccas.ac.cn.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Fang
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D050197:Atherosclerosis / Q000209:etiology / Q000235:genetics*; D016466:CHO Cells; D002448:Cell Adhesion / Q000235:genetics / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D015870:Gene Expression; D020022:Genetic Predisposition to Disease; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism; D016177:Macrophage-1 Antigen / Q000378:metabolism; D018625:Microscopy, Atomic Force; D020641:Polymorphism, Single Nucleotide; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: C573420:ICAM1 protein, human; D016177:Macrophage-1 Antigen; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1
keywords: Atomic force microscopy; Gene polymorphisms; Intercellular adhesion molecule-1; Single molecule force