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Titolo:
Urokinase receptor (CD87) aggregation triggers phosphoinositide hydrolysisand intracellular calcium mobilization in mononuclear phagocytes
Autore:
Sitrin, RG; Pan, PM; Harper, HA; Blackwood, RA; Todd, RF;
Indirizzi:
Univ Michigan, Dept Internal Med, Div Pulm & Crit Care Med, Ann Arbor, MI 48109 USA Univ Michigan Ann Arbor MI USA 48109 it Care Med, Ann Arbor, MI 48109 USA Univ Michigan, Dept Internal Med, Div Hematol Oncol, Ann Arbor, MI 48109 USA Univ Michigan Ann Arbor MI USA 48109 matol Oncol, Ann Arbor, MI 48109 USA Univ Michigan, Dept Pediat & Commicable Dis, Ann Arbor, MI 48109 USA Univ Michigan Ann Arbor MI USA 48109 micable Dis, Ann Arbor, MI 48109 USA
Titolo Testata:
JOURNAL OF IMMUNOLOGY
fascicolo: 11, volume: 163, anno: 1999,
pagine: 6193 - 6200
SICI:
0022-1767(199912)163:11<6193:UR(ATP>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
PLASMINOGEN-ACTIVATOR RECEPTOR; HUMAN-MONOCYTES; COMPLEMENT RECEPTOR-TYPE-3; SIGNAL TRANSDUCTION; ENDOTHELIAL-CELLS; CELLULAR RECEPTOR; HUMAN NEUTROPHILS; HT-1080 CELLS; VITRONECTIN; INHIBITOR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Sitrin, RG 6301 MSRB 3,Box 0642,1500 W Med Ctr Dr, Ann Arbor, MI 48109 USA 6301 MSRB 3,Box 0642,1500 W Med Ctr Dr Ann Arbor MI USA 48109
Citazione:
R.G. Sitrin et al., "Urokinase receptor (CD87) aggregation triggers phosphoinositide hydrolysisand intracellular calcium mobilization in mononuclear phagocytes", J IMMUNOL, 163(11), 1999, pp. 6193-6200

Abstract

Leukocytes utilize urokinase receptors (uPAR; CD87) in adhesion, migration, and matrix proteolysis. uPAR aggregate at cell-substratum interfaces and at leading edges of migrating cells, so this study was undertaken to determine whether uPAR aggregation is capable of initiating activation signaling. Monocyte-like U937 cells were labeled with fluo-3-acetoxymethyl ester to quantitate intracellular Ca2+ concentrations ([Ca2+](i)) by spectrofluorometry, and uPAR was aggregated by mAb cross-linking. uPAR aggregation induced highly reproducible increases in [Ca2+](i) of 103.0 +/- 10.9 nM (p < 0.0001) and >3-fold increases in cellular d-myoinositol 1,4,5-trisphosphate (Ins(1,4,5)P-3) levels. Similar increases in [Ca2+](i) were also elicited by uPAR aggregation in human monocytes, but cross-linking a control IgG2a had no effect on [Ca2+](i). Selectively cross-linking uPA-occupied uPAR with an anti-uPA mAb produced smaller increases in [Ca2+](i), but fully saturating uPAR with exogenous uPA enhanced the [Ca2+](i) response to equal the effect of aggregating uPAR directly. Increased [Ca2+](i) was inhibited by thapsigargin, herbimycin A, and U73122, but only partially reduced by low extracellular [Ca2+], indicating that uPAR aggregation increases [Ca2+](i) by activating phospholipase C through a tyrosine kinase-dependent mechanism, generating Ins(1,4,5)P-3 and releasing Ca2+ from Ins(1,4,5)P-3-sensitive intracellular stores. Cross-linking the beta(2) integrin CR3 could not duplicate the effect of uPAR cross-linking, and uPAR-triggered Ca2+ mobilization was not blocked by anti-CR3 mAbs, These results indicate that uPAR aggregation initiates phosphoinositide hydrolysis by mechanisms that are not strictly dependent on associated uPA or CR3.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 09:23:41