Binding of the cytoplasmic domain of intercellular adhesion molecule-2 (ICAM-2) to alpha-actinin.
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.
Heiska
L
L
Department of Pathology, Division of Biochemistry, University of Helsinki, FIN-00014 Helsinki, Finland.
Kantor
C
C
Parr
T
T
Critchley
D R
DR
Vilja
P
P
Gahmberg
C G
CG
Carpén
O
O
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
D015703:Antigens, CD; D002413:Cations, Divalent; D015815:Cell Adhesion Molecules; C065289:ICAM2 protein, human; D010446:Peptide Fragments; D000185:Actinin; D018799:Intercellular Adhesion Molecule-1