Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The catalytically inactive precursor of urokinase-type plasminogen activator (pro-u-PA) induced a chemotactic response in rat smooth muscle cells (RSMC) through binding to the membrane receptor of urokinase (u-PA receptor [u-PAR]). A soluble form of u-PAR activated by chymotrypsin cleavage as well as a peptide located between domain 1 and 2 of u-PAR reproduced the effect of pro-u-PA on cell migration. The chemotactic pro-u-PA effect correlates with a dramatic reorganization of actin cytoskeleton, of adhesion plaques, and with major cell shape changes in RSMC. Pro-u-PA induced a decrease in stress fiber content, membrane ruffling, actin ring formation, and disruption leading to the characteristic elongated cell shape of motile cells with an actin semi-ring located close to the leading edge of cells. u-PAR effects on both chemotaxis and cytoskeleton were sensitive to pertussis toxin and, hence, possibly require G proteins. u-PAR effects are accompanied by a relocation of u-PAR, vitronectin receptor (VNR) alphavbeta3, beta1 integrin subunit, and Src tyrosine kinase to the leading membrane of migrating cells. In conclusion, our data show that pro-u-PA, via binding to u-PAR, controls a signaling pathway, regulated by tyrosine kinases and possibly G proteins, leading to cell cytoskeleton reorganization and cell migration.
 ...
PMID:Src-dependence and pertussis-toxin sensitivity of urokinase receptor-dependent chemotaxis and cytoskeleton reorganization in rat smooth muscle cells. 1039 32

Trypsin is widely expressed in various non-pancreatic tissues at low levels and overexpressed in some types of human cancers. In the present study, we found that trypsin stimulates integrin-dependent adhesion and growth of MKN-1 human gastric carcinoma cells. MKN-1 cells expressed both proteinase-activated receptor-1 (PAR-1) and PAR-2, which are activated by thrombin and trypsin, respectively. Both trypsin and the PAR-2 ligand SLIGKV promoted integrin alpha(5)beta(1)-mediated adhesion of MKN-1 cells to fibronectin, and less effectively integrin alpha(v)beta(3)-mediated cell adhesion to vitronectin, but not that to type IV collagen or laminin-1 at all. Thrombin and the PAR-1 ligand SFLLRN promoted the cell adhesion to vitronectin more strongly than trypsin or the PAR-2 ligand, but not the cell adhesion to fibronectin at all. The cell adhesion-stimulating effect of the PAR-2 ligand was significantly reduced by the pre-treatment of cells with trypsin, indicating that the effect of trypsin is mediated by PAR-2 activation. The trypsin-stimulated cell adhesion to vitronectin, but not to fibronectin, was effectively inhibited by the G(i) protein blocker pertussis toxin, and both cell adhesions were completely inhibited by the Src kinase inhibitor herbimycin A. Furthermore, trypsin and the PAR-2 ligand stimulated growth of MKN-1 cells more strongly than thrombin or the PAR-1 ligand. These results show that trypsin regulates cellular adhesion and proliferation by inducing PAR-2/G protein signalings, and that the integrin alpha(5)beta(1)- and integrin alpha(v)beta(3)-dependent cell adhesions are regulated by different PAR/G protein signalings.
 ...
PMID:Trypsin stimulates integrin alpha(5)beta(1)-dependent adhesion to fibronectin and proliferation of human gastric carcinoma cells through activation of proteinase-activated receptor-2. 1067 85

Protease-activated receptor-2 (PAR-2) plays a role in inflammatory reactions in airway physiology. Proteases cleaving the extracellular NH(2) terminus of receptors activate or inactivate PAR, thus possessing a therapeutic potential. Using RT-PCR and immunocytochemistry, we show PAR-2 in human airway epithelial cell lines human bronchial epithelial (HBE) and A549. Functional expression of PAR-2 was confirmed by Ca(2+) imaging studies using the receptor agonist protease trypsin. The effect was abolished by soybean trypsin inhibitor and mimicked by the specific PAR-2 peptide agonist SLIGKV. Amplitude and duration of PAR-2-elicited Ca(2+) response in HBE and A549 cells depend on concentration and time of agonist superfusion. The response is partially pertussis toxin (PTX) insensitive, abolished by the phospholipase C inhibitor U-73122, and diminished by the inositol 1,4,5-trisphosphate receptor antagonist 2-aminoethoxydiphenyl borate. Cathepsin G altered neither the resting Ca(2+) level nor PAR-2-elicited Ca(2+) response. Thermolysin, a prototypic bacterial metalloprotease, induced a dose-dependent Ca(2+) response in HBE, but not A549, cells. In both cell lines, thermolysin abolished the response to a subsequent trypsin challenge but not to SLIGKV. Thus different epithelial cell types express different PAR-2 with identical responses to physiological stimuli (trypsin, SLIGKV) but different sensitivity to modifying proteases, such as thermolysin.
 ...
PMID:Human bronchial epithelial cells express PAR-2 with different sensitivity to thermolysin. 1200 91

(1) Thrombin, a mitogen for human cultured airway smooth muscle (HASM), has many actions that have been attributed to activation of protease-activated receptor (PARs). However, the role of PARs in the proliferative action has not been clearly identified. Moreover, thrombin elicits cytokine production in a number of cell types, but these effects have not been characterized in human ASM. (2) Thrombin (0.03-3 U ml(-1))-stimulated increases in the levels of the pro-inflammatory and fibrogenic cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF) were observed over the same concentration range observed for thrombin-stimulated mitogenesis. (3) Inhibition of thrombin proteolytic activity, with either D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (PPACK)- or hirudin-treated thrombin (0.3 U ml(-1)) or in the presence of the thrombin serine protease-selective inhibitor, SDZ 217-766 (0.15 micro M), reduced the thrombin-stimulated GM-CSF levels by 91+/-3, 65+/-12 and 83+/-9% (n=8, P<0.05), respectively. PPACK treatment, hirudin and SDZ 217-766 inhibited thrombin-stimulated increase in cell number by 70+/-8, 63+/-11 and 69+/-8%, respectively. (4) PAR-selective peptides SFLLRN (PAR1; 10 micro M), SLIGKV (PAR2; 10 micro M), GYPGQV (PAR4; 100 micro M) or the combination of SFLLRN and GYPGQV elicited mitogenic responses of only 15% of that to thrombin and surprisingly, had no effect on GM-CSF levels (n=8). Nevertheless, inhibition of thrombin responses by pertussis toxin (50 ng ml(-1)) suggests that the PAR-independent actions also involve a G-protein-coupled receptor. (5) PAR1 receptor expression was evident by immunohistochemistry and these receptors were coupled to increases in intracellular calcium, but not to the phosphorylation of ERK or the increases in cyclin D1 protein levels that are essential for cell proliferation. Cross-desensitization of intracellular calcium increases by thrombin and the PAR1-selective peptide provides evidence that the PAR1 receptor responds to both ligands. (6) The failure of PAR-selective peptides to mimic thrombin responses together with the inhibition of thrombin responses by serine protease inhibitors suggest the involvement of novel proteolytic receptor targets for thrombin-induced mitogenesis and cytokine production.
 ...
PMID:Protease-activated receptor (PAR)-independent growth and pro-inflammatory actions of thrombin on human cultured airway smooth muscle. 1264 88

Proteinase-activated receptors 1 and 4 (PAR(1) and PAR(4)) are the major receptors mediating thrombin-induced NO production in endothelial cells. The intracellular signaling following their activation still remains to be elucidated. The present study provides the first evidence for the distinct Ca(2+) requirement for the NO production between PAR(1) and PAR(4). The activation of PAR(1) by the activating peptide (PAR(1)-AP) elevated cytosolic Ca(2+) concentrations ([Ca(2+)](i)) and activated NO production in porcine aortic and human umbilical vein endothelial cells, whereas it had little effect on bovine aortic endothelial cells. PAR(4) activation by PAR(4)-AP consistently induced NO production without an appreciable [Ca(2+)](i) elevation in three types of endothelial cells. The PAR(1)-mediated NO production was significantly inhibited by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), whereas the PAR(4)-mediated NO production was resistant. NO production following the PAR(1) and PAR(4) activation was significantly inhibited by pertussis toxin, but it was resistant to a Galpha(q/11) inhibitor, YM254890 [(1R)-1-[(3S,6S,9S,12S,18R,21S,22R)-21-acetamido-18-benzyl-3-[(1R)-1-methoxyethyl]-4,9,10,12,16,22-hexamethyl-15-methylene-2,5,8,11,14,17,20-heptaoxo-1,19-dioxa-4,7,10,13,16-pentaazacyclodocosan-6-yl]-2-methylpropyl rel-(2S,3R)-2-acetamido-3-hydroxy-4-methylpentanoate]. However, YM254890 abrogated the PAR(1)-mediated Ca(2+) signal. PAR(4)-mediated NO production was substantially inhibited by the inhibitors of phosphotidylinositol-3 kinase (PI3K) and Akt, as well as by the dominant negative mutant of Akt. The PAR(1)-mediated NO production was relatively resistant to inhibitors of PI3K. An immunoblot analysis revealed a transient increase in the phosphorylation of Akt and endothelial NO synthase following the PAR(4) stimulation. In conclusion, PAR(1) and PAR(4) engage distinct signal transduction mechanisms to activate NO production in vascular endothelial cells. PAR(4) preferably activates Galpha(i/o) and induced NO production in a manner mostly independent of Ca(2+) but dependent on the PI3K/Akt pathway, whereas PAR(1) activates both the Ca(2+)-dependent and -independent mechanisms.
 ...
PMID:Distinct Ca2+ requirement for NO production between proteinase-activated receptor 1 and 4 (PAR1 and PAR4) in vascular endothelial cells. 1749 65

We evaluated the ability of different trypsin-revealed tethered ligand (TL) sequences of rat proteinase-activated receptor 2 (rPAR(2)) and the corresponding soluble TL-derived agonist peptides to trigger agonist-biased signaling. To do so, we mutated the proteolytically revealed TL sequence of rPAR(2) and examined the impact on stimulating intracellular calcium transients and mitogen-activated protein (MAP) kinase. The TL receptor mutants, rPAR(2)-Leu(37)Ser(38), rPAR(2)-Ala(37-38), and rPAR(2)-Ala(39-42) were compared with the trypsin-revealed wild-type rPAR(2) TL sequence, S(37)LIGRL(42)-. Upon trypsin activation, all constructs stimulated MAP kinase signaling, but only the wt-rPAR(2) and rPAR(2)-Ala(39-42) triggered calcium signaling. Furthermore, the TL-derived synthetic peptide SLAAAA-NH2 failed to cause PAR(2)-mediated calcium signaling but did activate MAP kinase, whereas SLIGRL-NH2 triggered both calcium and MAP kinase signaling by all receptors. The peptides AAIGRL-NH2 and LSIGRL-NH2 triggered neither calcium nor MAP kinase signals. Neither rPAR(2)-Ala(37-38) nor rPAR(2)-Leu(37)Ser(38) constructs recruited beta-arrestins-1 or -2 in response to trypsin stimulation, whereas both beta-arrestins were recruited to these mutants by SLIGRL-NH2. The lack of trypsin-triggered beta-arrestin interactions correlated with impaired trypsin-activated TL-mutant receptor internalization. Trypsin-stimulated MAP kinase activation by the TL-mutated receptors was not blocked by inhibitors of Galpha(i) (pertussis toxin), Galpha(q) [N-cyclohexyl-1-(2,4-dichlorophenyl)-1,4-dihydro-6-methylindeno[1,2-c]pyrazole-3-carboxamide (GP2A)], Src kinase [4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]-pyrimidine (PP1)], or the epidermal growth factor (EGF) receptor [4-(3'-chloroanilino)-6,7-dimethoxy-quinazoline (AG1478)], but was inhibited by the Rho-kinase inhibitor (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide, 2HCl (Y27362). The data indicate that the proteolytically revealed TL sequence(s) and the mode of its presentation to the receptor (tethered versus soluble) can confer biased signaling by PAR(2), its arrestin recruitment, and its internalization. Thus, PAR(2) can signal to multiple pathways that are differentially triggered by distinct proteinase-revealed TLs or by synthetic signal-selective activating peptides.
 ...
PMID:Agonist-biased signaling via proteinase activated receptor-2: differential activation of calcium and mitogen-activated protein kinase pathways. 1960 24

The protease-activated receptors (PAR1 and PAR2) are unusual G protein-coupled receptors that are activated by distinct serine proteases and are coexpressed in many different cell types. Limited recent evidence suggests these closely related receptors regulate different physiological outputs in the same cell, although little is known about the comparative signaling pathways used by these receptors. Here we report that PAR1 and PAR2 couple to overlapping and distinct sets of G proteins to regulate receptor-specific signaling pathways involved in cell migration. In functionally PAR-null COS-7 cells, ectopically expressed PAR1 and PAR2 both form stable complexes with G alpha(q), G alpha(11), G alpha(14), G alpha(12), and G alpha(13). It is surprising that PAR1 but not PAR2 coupled to G alpha(o), G alpha(i1), and G alpha(i2). Consistent with these observations, PAR1 and PAR2 stimulation of inositol phosphate production and RhoA activation was blocked by specific inhibitors of G(q/11) and G(12/13) signaling, respectively. Both receptors stimulated extracellular signal-regulated kinase (ERK) 1/2 phosphorylation, but only PAR1 inhibited adenylyl cyclase activity, and pertussis toxin blocked PAR1 effects on both adenylyl cyclase and ERK1/2 signaling. Neu7 astrocytes express native PAR1 and PAR2 receptors that activate inositol phosphate, RhoA, and ERK1/2 signaling. However, only PAR1 inhibited adenylyl cyclase activity. PAR1 and PAR2 also stimulate Neu7 cell migration. PAR1 effects on ERK1/2 phosphorylation and cell migration were blocked both by pertussis toxin and by the mitogen-activated protein kinase kinase/ERK inhibitor [1,4-diamino-2,3-dicyano-1,4-bis(methylthio)butadiene (U0126)], whereas PAR2 effects were only blocked by U0126. These studies demonstrate that PAR1 and PAR2 physically and functionally link to overlapping and distinct profiles of G proteins to differentially regulate downstream signaling pathways and cell physiology.
 ...
PMID:PAR1 and PAR2 couple to overlapping and distinct sets of G proteins and linked signaling pathways to differentially regulate cell physiology. 2021 60

hPAR(2) (human proteinase-activated receptor-2) is a member of the novel family of proteolytically activated GPCRs (G-protein-coupled receptors) termed PARs (proteinase-activated receptors). Previous pharmacological studies have found that activation of hPAR(2) by mast cell tryptase can be regulated by receptor N-terminal glycosylation. In order to elucidate other post-translational modifications of hPAR(2) that can regulate function, we have explored the functional role of the intracellular cysteine residue Cys(361). We have demonstrated, using autoradiography, that Cys(361) is the primary palmitoylation site of hPAR(2). The hPAR(2)C361A mutant cell line displayed greater cell-surface expression compared with the wt (wild-type)-hPAR(2)-expressing cell line. hPAR(2)C361A also showed a decreased sensitivity and efficacy (intracellular calcium signalling) towards both trypsin and SLIGKV. In stark contrast, hPAR(2)C361A triggered greater and more prolonged ERK (extracellular-signal-regulated kinase) phosphorylation compared with that of wt-hPAR(2) possibly through Gi, since pertussis toxin inhibited the ability of this receptor to activate ERK. Finally, flow cytometry was utilized to assess the rate and extent of receptor internalization following agonist challenge. hPAR(2)C361A displayed faster internalization kinetics following trypsin activation compared with wt-hPAR(2), whereas SLIGKV had a negligible effect on internalization for either receptor. In conclusion, palmitoylation plays an important role in the regulation of PAR(2) expression, agonist sensitivity, desensitization and internalization.
 ...
PMID:Palmitoylation of human proteinase-activated receptor-2 differentially regulates receptor-triggered ERK1/2 activation, calcium signalling and endocytosis. 2162 85

Among the post-translational modifications, ADP-ribosylation has been for long time the least integrated in the scheme of the structural protein modifications affecting physiological functions. In spite of the original findings on bacterial-dependent ADP-ribosylation catalysed by toxins such as cholera and pertussis toxin, only with the discovery of the poly-ADP-ribosyl polymerase (PARP) family the field has finally expanded and the role of ADP-ribosylation has been recognised in both physiological and pathological processes, including cancer, infectious and neurodegenerative diseases. This is now a rapidly expanding field of investigation, centred on the role of the different PARPs and their substrates in various diseases, and on the potential of PARP inhibitors as novel pharmacological tools to be employed in relevant pathological context. In this review we analyse the role that members of the PARP family and poly-ADP-ribose (PAR; the product of PARP1 and PARP5a activity) play in the processes following the exposure of cells to different stresses. The cell response that arises following conditions such as heat, osmotic, oxidative stresses or viral infection relies on the formation of stress granules, which are transient cytoplasmic membrane-less structures, that include untranslated mRNA, specific proteins and PAR, this last one serving as the "collector" of all components (that bind to it in a non-covalent manner). The resulting phenotypes are cells in which translation, intracellular transport or pro-apoptotic pathways are reversibly inhibited, for the time the given stress holds. Interestingly, the formation of defective stress granules has been detected in diverse pathological conditions including neurological disorders and cancer. Analysing the molecular details of stress granule formation under these conditions offers a novel view on the pathogenesis of these diseases and, as a consequence, the possibility of identifying novel drug targets for their treatment.
 ...
PMID:PARPs and PAR as novel pharmacological targets for the treatment of stress granule-associated disorders. 3110 82