scholarly journals Yaba-like disease virus protein 7L is a cell-surface receptor for chemokine CCL1

2003 ◽  
Vol 84 (12) ◽  
pp. 3325-3336 ◽  
Author(s):  
Pilar Najarro ◽  
Han-Joo Lee ◽  
James Fox ◽  
James Pease ◽  
Geoffrey L. Smith
Keyword(s):  
Cell Surface ◽  
Disease Virus ◽  
Chemokine Receptor ◽  
Amino Acid Identity ◽  
Cell Surface Receptor ◽  
Cell Protein ◽  
Virus Protein ◽  
Expression Of Genes ◽  
Surface Receptor ◽  
Species Specific

Yaba-like disease virus (YLDV) genes 7L and 145R are located on opposite ends of the genome and are predicted to encode 7-transmembrane proteins (7-TM) that share 53 and 44 % amino acid identity, respectively, to human CC chemokine receptor 8 (hCCR8). In this report, we demonstrate that early after infection with YLDV, cells acquire the ability to bind human CCL1. By expression of genes 7L and 145R in vaccinia virus, we demonstrated that each protein is glycosylated and is exposed on the cell surface with the N terminus outside the cell. Protein 7L, but not 145R, is able to bind hCCL1 (K d=0·6±0·13 nM) and couple to heterotrimeric G-proteins and to activate the extracellular signal-regulated kinases (ERK1/2). 7L binds several chemokines including the viral chemokines vMIPI and vMIPII and hCCL7/MCP3. This binding seems species-specific as 7L does not bind the murine orthologues of CCL1 and CCL7 in the assays used. This represents the first example of a poxviral 7-TM chemokine receptor that has functional interactions with a human chemokine.

scholarly journals Activation Mechanism of Anticoagulant Protein C in Large Blood Vessels Involving the Endothelial Cell Protein C Receptor

1998 ◽  
Vol 187 (7) ◽  
pp. 1029-1035 ◽  
Author(s):  
Kenji Fukudome ◽  
Xiaofen Ye ◽  
Naoko Tsuneyoshi ◽  
Osamu Tokunaga ◽  
Keishin Sugawara ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Blood Coagulation ◽  
Protein C ◽  
Cell Surface Receptor ◽  
Activation Mechanism ◽  
Cell Protein ◽  
Endothelial Cell Surface ◽  
Surface Receptor ◽  
Large Vessels

Protein C is an important regulatory mechanism of blood coagulation. Protein C functions as an anticoagulant when converted to the active serine protease form on the endothelial cell surface. Thrombomodulin (TM), an endothelial cell surface receptor specific for thrombin, has been identified as an essential component for protein C activation. Although protein C can be activated directly by the thrombin–TM complex, the conversion is known as a relatively low-affinity reaction. Therefore, protein C activation has been believed to occur only in microcirculation. On the other hand, we have identified and cloned a novel endothelial cell surface receptor (EPCR) that is capable of high-affinity binding of protein C and activated protein C. In this study, we demonstrate the constitutive, endothelial cell–specific expression of EPCR in vivo. Abundant expression was particularly detected in the aorta and large arteries. In vitro cultured, arterial endothelial cells were also found to express abundant EPCR and were capable of promoting significant levels of protein C activation. EPCR was found to greatly accelerate protein C activation by examining functional activity in transfected cell lines expressing EPCR and/or TM. EPCR decreased the dissociation constant and increased the maximum velocity for protein C activation mediated by the thrombin–TM complex. By these mechanisms, EPCR appears to enable significant levels of protein C activation in large vessels. These results suggest that the protein C anticoagulation pathway is important for the regulation of blood coagulation not only in microvessels but also in large vessels.

Expression, function, and localization of the REG cell surface receptor

2001 ◽  
Vol 120 (5) ◽  
pp. A18-A19
Author(s):  
B DIECKGRAEFE ◽  
C HOUCHEN ◽  
H ZHANG
Keyword(s):  
Cell Surface ◽  
Cell Surface Receptor ◽  
Surface Receptor

Inhibition of rat ventricular automaticity by adenosine

1985 ◽  
Vol 248 (6) ◽  
pp. H907-H913 ◽  
Author(s):  
L. J. Heller ◽  
R. A. Olsson
Keyword(s):  
Cell Surface ◽  
Cell Surface Receptor ◽  
Chronotropic Effect ◽  
Surface Receptors ◽  
Adenosine Concentration ◽  
Surface Receptor ◽  
Ventricular Automaticity ◽  
Beating Rate ◽  
Chronotropic Effects ◽  
Developed Pressure

This study was designed to characterize adenosine's negative chronotropic effect on ventricular pacemakers. The spontaneous beating rate of isolated, isovolumic rat ventricular preparations perfused with Krebs-Henseleit solution decreased as the adenosine concentration was increased [log M effective concentration 50% (EC50) = -5.22 +/- 0.17]. The lack of effect of propranolol or atropine on this adenosine response eliminates the involvement of endogenous neurotransmitters. Support for the involvement of an external cell surface receptor was provided by findings that theophylline and 8-(4-sulfophenyl)theophylline, an analogue thought to act solely at the cell surface, significantly increased the adenosine log M EC50 to -3.94 +/- 0.22 and -3.61 +/- 0.22, respectively. An increase in spontaneous beating rate induced by theophylline, but not by its analogue, was blocked by the addition of propranolol. The relative chronotropic potency of the adenosine analogues R-PIA, S-PIA, and NECA suggests that the cell surface receptors may be of the Ri type. The negative chronotropic effects of adenosine and its analogues occurred at concentrations that had no effect on the developed pressure of the paced preparation. Electrocardiographic evaluations indicate that at high agonist concentrations, there was an abrupt alteration in electrical properties of the preparation, which could be blocked by theophylline and its analogue.

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