title: Heterodimerization of integrin Mac-1 subunits studied by single-molecule imaging.
abstract: Heterodimerization of integrin Mac-1 (alpha(M)beta(2)) subunits plays important role on regulating leukocytes adhesion to extracellular matrix or endothelial cells. Here, using total internal reflection microscopy, we investigated the heterodimerization of integrin Mac-1 subunits at the single-molecule level in live cells. Individual alpha(M) subunit fused to the enhanced yellow fluorescent protein (eYFP) was imaged at the basal plasma membrane of live Chinese hamster ovary (CHO) cells. Through analysis of mean square displacement (MSD), diffusion coefficient, the size of restricted domain and fraction of molecules undergoing restricted diffusion, we found that as compared with the diffusion in the absence of beta(2) subunit, the diffusion of single-molecule of alpha(M)-YFP was suppressed significantly in the presence of beta(2) subunit. Thus, based on the oligomerization-induced trapping model, we suggested that in the presence of beta(2) subunit, the alpha(M) subunit may form heterodimer with it.
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 390 Qing-he Road, Shanghai 201800, China.
authors.forename: Guo
authors.initials: G
authors.lastname: Fu
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Gui-Ying
authors.initials: GY
authors.lastname: Wang
authors.forename: Yi-Zhang
authors.initials: YZ
authors.lastname: Chen
authors.forename: Zhi-Zhan
authors.initials: ZZ
authors.lastname: Xu
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry; D018821:CD18 Antigens / Q000737:chemistry*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004058:Diffusion; D019281:Dimerization; D006801:Humans; D008164:Luminescent Proteins / Q000737:chemistry; D008856:Microscopy, Fluorescence; D021122:Protein Subunits
chemical_list: D001426:Bacterial Proteins; D018821:CD18 Antigens; D008164:Luminescent Proteins; D021122:Protein Subunits; C054562:yellow fluorescent protein, Bacteria