Association of ICAM-1 with the cytoskeleton in rat alveolar epithelial cells in primary culture.
Intercellular adhesion molecule-1 ICAM-1) is a transmembrane adhesion protein that is expressed constitutively on the apical surface of type I cells in vivo and on type II cells in vitro as they spread in culture, assuming type I cell-like characteristics. To investigate the possible interaction of ICAM-1 with the alveolar epithelial cell cytoskeleton, rat type II cells in primary culture were extracted with nonionic detergent, and residual ICAM-1 associated with the cytoskeletal remnants was determined using immunofluorescence microscopy, immunoprecipitation, and cell-based enzyme-linked immunosorbent assay. A large fraction of alveolar epithelial cell ICAM-1 remained associated with the cytoskeleton after detergent extraction, whereas two other transmembrane molecules, transferrin receptor and class II major histocompatibility complex, were completely removed. ICAM-1 was redistributed on the cell surface after the disruption of actin filaments with cytochalasin B, suggesting interaction with the actin cytoskeleton. In contrast, ICAM-1 was completely detergent soluble in rat pulmonary artery endothelial cells, human umbilical vein endothelial cells, and rat alveolar macrophages. The association of ICAM-1 with the alveolar epithelial cell cytoskeleton was not altered after stimulation with inflammatory cytokines. However, detergent resistant ICAM-1 was significantly increased after crosslinking of ICAM-1 on the cell surface, suggesting that this cytoskeletal association may be modulated by interactions of alveolar epithelial cells with inflammatory cells. The association of ICAM-1 with the cytoskeleton in alveolar epithelial cells may provide a fixed intermediary between mobile inflammatory cells and the alveolar surface.
Barton
W W
WW
Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0360, USA.
Wilcoxen
S E
SE
Christensen
P J
PJ
Paine
R
R
D000199:Actins / Q000032:analysis; D000818:Animals; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis*; D016676:Macrophages, Alveolar / Q000166:cytology / Q000502:physiology*; D008297:Male; D011650:Pulmonary Alveoli / Q000166:cytology / Q000502:physiology*; D011651:Pulmonary Artery; D051381:Rats; D017207:Rats, Sprague-Dawley; D014471:Umbilical Veins
D000199:Actins; D018799:Intercellular Adhesion Molecule-1