scholarly journals Low Density Lipoprotein (LDL) Receptor-related Protein 1B Impairs Urokinase Receptor Regeneration on the Cell Surface and Inhibits Cell Migration

2002 ◽  
Vol 277 (44) ◽  
pp. 42366-42371 ◽  
Author(s):  
Yonghe Li ◽  
Jane M. Knisely ◽  
Wenyan Lu ◽  
Lynn M. McCormick ◽  
Jieyi Wang ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Surface ◽  
Low Density Lipoprotein ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Urokinase Receptor ◽  
Low Density ◽  
Related Protein

scholarly journals Participation of the urokinase receptor in neutrophil efferocytosis

Blood ◽  
2009 ◽  
Vol 114 (4) ◽  
pp. 860-870 ◽  
Author(s):  
Young-Jun Park ◽  
Gang Liu ◽  
Yuko Tsuruta ◽  
Emmanuel Lorne ◽  
Edward Abraham
Keyword(s):  
Cell Migration ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Urokinase Receptor ◽  
Low Density ◽  
Related Protein ◽  
Wild Type ◽  
Arginine Glycine Aspartic Acid

AbstractThe urokinase receptor (uPAR) plays an important role in regulation of fibronolysis, cell migration, and adhesion. In this study, we examined whether uPAR plays a role in modulating efferocytosis of neutrophils. Macrophages from uPAR−/− mice demonstrated enhanced ability to engulf viable wild-type (WT) neutrophils in vitro and in vivo in the lungs. The increased phagocytic activity of uPAR−/− macrophages was abrogated by incubation with soluble uPAR (suPAR), arginine-glycine-aspartic acid (RGD)–containing peptides, or anti-integrin antibodies. There was increased uptake of viable uPAR−/− neutrophils by WT macrophages. Incubation of uPAR−/− neutrophils with suPAR or anti-integrin antibodies diminished uptake by WT macrophages to baseline. Uptake of uPAR−/− neutrophils by uPAR−/− macrophages was not enhanced. However, incubation of uPAR−/− neutrophils or uPAR−/− macrophages, but not both, with suPAR enhanced the uptake of viable uPAR−/− neutrophils by uPAR−/− macrophages. The adhesion of WT neutrophils to uPAR−/− macrophages was higher than to WT macrophages. uPAR−/− neutrophils demonstrated increased adhesion to suPAR, which was abrogated by blocking of low-density lipoprotein related protein and integrins. Expression of uPAR on the surface of apoptotic neutrophils was reduced compared with levels on viable neutrophils. These results demonstrate a novel role for uPAR in modulating recognition and clearance of neutrophils.

scholarly journals The low-density lipoprotein receptor-related protein 1 (LRP1) mediates the endocytosis of the cellular prion protein

2007 ◽  
Vol 402 (1) ◽  
pp. 17-23 ◽  
Author(s):  
David R. Taylor ◽  
Nigel M. Hooper
Keyword(s):  
Prion Protein ◽  
Low Density Lipoprotein ◽  
Neuronal Cells ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Adaptor Protein ◽  
Cellular Prion Protein ◽  
Low Density ◽  
Related Protein ◽  
Density Lipoprotein Receptor

PrPC (cellular prion protein) is located at the surface of neuronal cells in detergent-insoluble lipid rafts, yet is internalized by clathrin-dependent endocytosis. As PrPC is glycosyl-phosphatidylinositol-anchored, it requires a transmembrane adaptor protein to connect it to the clathrin endocytosis machinery. Using receptor-associated protein and small interfering RNA against particular LDL (low-density lipoprotein) family members, in combination with immunofluorescence microscopy and surface biotinylation assays, we show that the transmembrane LRP1 (LDL receptor-related protein 1) is required for the Cu2+-mediated endocytosis of PrPC in neuronal cells. We show also that another LRP1 ligand that can cause neurodegenerative disease, the Alzheimer's amyloid precursor protein, does not modulate the endocytosis of PrPC.

scholarly journals Dual interaction of the malaria circumsporozoite protein with the low density lipoprotein receptor-related protein (LRP) and heparan sulfate proteoglycans.

1996 ◽  
Vol 184 (5) ◽  
pp. 1699-1711 ◽  
Author(s):  
M Shakibaei ◽  
U Frevert
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Heparan Sulfate Proteoglycans ◽  
Low Density ◽  
Lipoprotein Receptor ◽  
Related Protein ◽  
Density Lipoprotein Receptor ◽  
Lipoprotein Receptor Related Protein

Speed and selectivity of hepatocyte invasion by malaria sporozoites have suggested a receptor-mediated mechanism and the specific interaction of the circumsporozoite (CS) protein with liver-specific heparan sulfate proteoglycans (HSPGs) has been implicated in the targeting to the liver. Here we show that the CS protein interacts not only with cell surface heparan sulfate, but also with the low density lipoprotein receptor-related protein (LRP). Binding of 125I-CS protein to purified LRP occurs with a Kd of 4.9 nM and can be inhibited by the receptor-associated protein (RAP). Blockage of LRP by RAP or anti-LRP antibodies on heparan sulfate-deficient CHO cells results in more than 90% inhibition of binding and endocytosis of recombinant CS protein. Conversely, blockage or enzymatic removal of the cell surface heparan sulfate from LRP-deficient embryonic mouse fibroblasts yields the same degree of inhibition. Heparinase-pretreatment of LRP-deficient fibroblasts or blockage of LRP on heparan sulfate-deficient CHO cells by RAP, lactoferrin, or anti-LRP antibodies reduces Plasmodium berghei invasion by 60-70%. Parasite development in heparinase-pretreated HepG2 cells is inhibited by 65% when RAP is present during sporozoite invasion. These findings suggest that malaria sporozoites utilize the interaction of the CS protein with HSPGs and LRP as the major mechanism for host cell invasion.

scholarly journals Low density lipoprotein receptor–related protein is a calreticulin coreceptor that signals focal adhesion disassembly

2003 ◽  
Vol 161 (6) ◽  
pp. 1179-1189 ◽  
Author(s):  
Anthony Wayne Orr ◽  
Claudio E. Pedraza ◽  
Manuel Antonio Pallero ◽  
Carrie A. Elzie ◽  
Silvia Goicoechea ◽  
...  
Keyword(s):  
Cell Surface ◽  
Focal Adhesion ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein Receptor ◽  
Related Protein ◽  
Low Density Lipoprotein Receptor ◽  
Density Lipoprotein Receptor ◽  
Lipoprotein Receptor Related Protein

Thrombospondin (TSP) signals focal adhesion disassembly (the intermediate adhesive state) through interactions with cell surface calreticulin (CRT). TSP or a peptide (hep I) of the active site induces focal adhesion disassembly through binding to CRT, which activates phosphoinositide 3-kinase (PI3K) and extracellular signal–related kinase (ERK) through Gαi2 proteins. Because CRT is not a transmembrane protein, it is likely that CRT signals as part of a coreceptor complex. We now show that low density lipoprotein receptor–related protein (LRP) mediates focal adhesion disassembly initiated by TSP binding to CRT. LRP antagonists (antibodies, receptor-associated protein) block hep I/TSP-induced focal adhesion disassembly. LRP is necessary for TSP/hep I signaling because TSP/hep I is unable to stimulate focal adhesion disassembly or ERK or PI3K signaling in fibroblasts deficient in LRP. LRP is important in TSP–CRT signaling, as shown by the ability of hep I to stimulate association of Gαi2 with LRP. The isolated proteins LRP and CRT interact, and LRP and CRT are associated with hep I in molecular complexes extracted from cells. These data establish a mechanism of cell surface CRT signaling through its coreceptor, LRP, and suggest a novel function for LRP in regulating cell adhesion.

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