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Tsakadze, Nina L., Sen, Utpal, Zhao, Zhendong, Sithu, Srinivas D., English, William R. 
ORCID: https://orcid.org/0000-0003-3024-2441 and D'Souza, Stanley E.
(2004)
Signals mediating cleavage of intercellular adhesion molecule-1.
American Journal of Physiology - Cell Physiology, 287 (1).
C55-C63.
ISSN 0363-6143
Abstract
ICAM-1, a membrane-bound receptor, is released as soluble ICAM-1 in inflammatory diseases. To delineate mechanisms regulating ICAM-1 cleavage, studies were performed in endothelial cells (EC), human embryonic kidney (HEK)-293 cells transfected with wild-type (WT) ICAM-1, and ICAM-1 containing single tyrosine-to-alanine substitutions (Y474A, Y476A, and Y485A) in the cytoplasmic region. Tyrosine residues at 474 and 485 become phosphorylated upon ICAM-1 ligation and associate with signaling modules. Cleavage was assessed by using an antibody against the cytoplasmic tail of ICAM-1, which recognizes intact ICAM-1 and the 7-kDa membrane-bound fragment remaining after cleavage. Cleavage in HEK-293 WT cells was accelerated by phorbol ester PMA, whereas in EC it was induced by tumor necrosis factor-α. In both cell types, a 7-kDa ICAM-1 remnant was detected. Tyrosine phosphatase inhibitors dephostatin and sodium orthovanadate augmented cleavage. PD-98059 (MEK kinase inhibitor), geldanamycin and PP2 (Src kinase inhibitors), and wortmannin (phosphatidylinositol 3-kinase inhibitor) dose-dependently inhibited cleavage in both cell types. SB-203580 (p38 inhibitor) was more effective in EC, and D609 (PLC inhibitor) mostly affected cleavage in HEK-293 cells. Cleavage was drastically decreased in Y474A and Y485A, whereas it was marginally reduced in Y476A. Surprisingly, phosphorylation was not detectable on the 7-kDa fragment of ICAM-1. These results implicate distinct pathways in the cleavage process and suggest a preferred signal transmission route for ICAM-1 shedding in the two cell systems tested. Tyrosine residues Y474 and Y485 within the cytoplasmic sequence of ICAM-1 regulate the cleavage process.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | sdg 3 - good health and well-being ,/dk/atira/pure/sustainabledevelopmentgoals/good_health_and_well_being |
| Faculty \ School: | Faculty of Medicine and Health Sciences > Norwich Medical School |
| UEA Research Groups: | Faculty of Medicine and Health Sciences > Research Centres > Metabolic Health |
| Depositing User: | LivePure Connector |
| Date Deposited: | 15 Dec 2022 10:31 |
| Last Modified: | 19 Oct 2023 03:30 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/90199 |
| DOI: | 10.1152/ajpcell.00585.2003 |
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