title: Binding of the cytoplasmic domain of intercellular adhesion molecule-2 (ICAM-2) to alpha-actinin.
abstract: Intercellular adhesion molecule-2 (ICAM-2) functions as a ligand for lymphocyte function-associated antigen-1 (LFA-1) and is involved in leukocyte adhesion. We studied intracellular associations of ICAM-2 using a peptide encompassing the cytoplasmic amino acids 231-254 as an affinity matrix. Among the proteins from placental lysates that bound to the peptide was alpha-actinin as demonstrated by immunoblotting. Purified, 125I-labeled alpha-actinin also bound to the peptide. Confocal microscopic analysis of Eahy926 cells demonstrated a colocalization of ICAM-2 and alpha-actinin. Of overlapping octapeptides covering the entire ICAM-2 cytoplasmic amino acids, ICAM-2241-248 bound alpha-actinin most avidly and effectively competed with the longer cytoplasmic peptide for binding. The site of interaction in alpha-actinin was studied using bacterially expressed alpha-actinin fusion proteins. Several constructs covering nonoverlapping regions of alpha-actinin bound to the ICAM-2 cytoplasmic peptide suggesting that multiple regions in alpha-actinin can mediate the interaction. These results, together with previously demonstrated interactions between alpha-actinin and the adhesion proteins ICAM-1, L-selectin, beta1- and beta2-integrins emphasize the role of alpha-actinin as a linker between cell surface adhesion molecules and the actin-containing cytoskeleton.
authors.affiliation: Department of Pathology, Division of Biochemistry, University of Helsinki, FIN-00014 Helsinki, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Heiska
authors.forename: C
authors.initials: C
authors.lastname: Kantor
authors.forename: T
authors.initials: T
authors.lastname: Parr
authors.forename: D R
authors.initials: DR
authors.lastname: Critchley
authors.forename: P
authors.initials: P
authors.lastname: Vilja
authors.forename: C G
authors.initials: CG
authors.lastname: Gahmberg
authors.forename: O
authors.initials: O
authors.lastname: Carpén
mesh_terms: D000185:Actinin / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002413:Cations, Divalent / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006822:Hybrid Cells; D018799:Intercellular Adhesion Molecule-1 / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D011489:Protein Denaturation
chemical_list: D015703:Antigens, CD; D002413:Cations, Divalent; D015815:Cell Adhesion Molecules; C065289:ICAM2 protein, human; D010446:Peptide Fragments; D000185:Actinin; D018799:Intercellular Adhesion Molecule-1