Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We developed previously VPAC(1) [vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating peptide (PACAP) receptor]>VPAC(2) receptor selective ligands. Replacement of the VIP-Thr(11) by an Arg(11) in these ligands contributed to their selectivity: Arg(11)-VIP had a 200-fold lower affinity when compared with VIP at VPAC(2) receptors as opposed to 3- to 5-fold higher affinity at VPAC(1) receptors. Comparison of the binding and functional properties of related VIP analogues suggested that the VPAC(1) selectivity of Arg(11)-VIP was due to the loss of a hydrogen bond between the hydroxy group of Thr residue and the VPAC(2) receptor, steric hindrance between the Arg side chain and the VPAC(2) receptor and charge attraction by the VPAC(1) receptor. Comparison of the ability of VIP analogues to activate adenylate cyclase through chimaeric VPAC(1)/VPAC(2) and VPAC(2)/VPAC(1) receptors indicated that the first extracellular receptor loop carried most of the VPAC(2) receptors' ability to discriminate VIP from Arg(11)-VIP. Based on results obtained for a truncated VPAC(2) receptor and the closely related PACAP-preferring receptor (PAC(1)) and secretin receptors, we hypothesized that Thr(11) interacted with the VPAC(2) receptor Tyr(184) (similar to the VPAC(1) receptor Phe(200) residue). The Y184F (Tyr(184)-->Phe) VPAC(2) mutant lost the ability to discriminate VIP from Val(11)-VIP, and the F200Y VPAC(1) mutant acquired the ability to discriminate the natural peptide from Val(11)-VIP. These results support the hypothesis that the hydroxy group of the native VIP-Thr(11) side chain can indeed form a hydrogen bond with the Tyr side chain in the VPAC(2) receptor.
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PMID:Evidence for a direct interaction between the Thr11 residue of vasoactive intestinal polypeptide and Tyr184 located in the first extracellular loop of the VPAC2 receptor. 1247 94

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables has been retrieved from the Clinical Studies knowledge area of Prous Science Integrity(R), the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: AdGVVEGF121.10, anakinra, andolast, anidulafungin, APC-2059, l-arginine hydrochloride, aripiprazole, arzoxifene hydrochloride, asimadoline; Bexarotene, bimatoprost, bimosiamose, bizelesin, BMS-188667, botulinum toxin type B, bromfenac sodium, bryostatin 1; Cannabidiol, cariporide mesilate, CCI-1004, CDP-571, cerivastatin sodium, clevudine; Dalbavancin, darbepoetin alfa, decitabine, deligoparin sodium, diethylnorspermine, drotrecogin alfa (activated), DTaP-HBV-IPV/Hib-vaccine; E-5564, eculizumab, edodekin alfa, emtricitabine, enfuvirtide, (-)-epigallocatechin gallate, eplerenone, esomeprazole magnesium, etaquine, etoricoxib, ezetimibe; Fesoterodine, fipamezole hydrochloride, fondaparinux sodium, fosamprenavir calcium, frovatriptan, fulvestrant; Gadofosveset sodium, galiximab, ghrelin (human), glufosfamide; Homoharringtonine; Idraparinux sodium, imatinib mesylate, INS-37217; KRN-7000; L-651582, lafutidine, lanthanum carbonate, lenercept, levetiracetam, lusupultide; Magnesium sulfate, melatonin, mepolizumab, midostaurin, morphine hydrochloride, mozavaptan; Natalizumab, nesiritide; OPC-51803, oregovomab, oritavancin; Peginterferon alfa-2(a), pleconaril, plevitrexed, prasterone, pregabalin; Ranibizumab, Ro-31-7453, roxifiban acetate, rubitecan; SCV-07, SHL-749, sho-saiko-to, soblidotin, solifenacin succinate; Tegaserod maleate, telithromycin, tenecteplase, theraCIM, tipifarnib, travoprost; Valdecoxib, vardenafil hydrochloride hydrate, voriconazole; Ximelagatran; Ziprasidone hydrochloride, ZYC-00101.
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PMID:Gateways to clinical trials. 1285 63

The Escherichia coli GABA (gamma-aminobutyric acid) permease, GabP, and other members of the APC (amine/polyamine/choline) transporter superfamily share a CAR (consensus amphipathic region) that probably contributes to solute translocation. If true, then the CAR should contain structural features that act as determinants of substrate specificity ( k (cat)/ K (m)). In order to address this question, we have developed a novel, expression-independent TSR (transport specificity ratio) analysis, and applied it to a series of 69 cysteine-scanning (single-cysteine) variants. The results indicate that GabP has multiple specificity determinants (i.e. residues at which an amino acid substitution substantially perturbs the TSR). Specificity determinants were found: (i) on a hydrophobic surface of the CAR (from Leu-267 to Ala-285), (ii) on a hydrophilic surface of the CAR (from Ser-299 to Arg-318), and (iii) in a cytoplasmic loop (His-233) between transmembrane segments 6 and 7. Overall, these observations show that (i) structural features within the CAR have a role in substrate discrimination (as might be anticipated for a transport conduit) and, interestingly, (ii) the substrate discrimination task is shared among specificity determinants that appear too widely dispersed across the GabP molecule to be in simultaneous contact with the substrates. We conclude that GabP exhibits behaviour consistent with a broadly applicable specificity delocalization principle, which is demonstrated to follow naturally from the classical notion that translocation occurs synchronously with conformational transitions that change the chemical potential of the bound ligand [Tanford (1982) Proc. Natl. Acad. Sci. U.S.A. 79, 2882-2884].
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PMID:Use of the transport specificity ratio and cysteine-scanning mutagenesis to detect multiple substrate specificity determinants in the consensus amphipathic region of the Escherichia coli GABA (gamma-aminobutyric acid) transporter encoded by gabP. 1295 24

1. The mechanisms and receptors involved in the vasoactive intestinal peptide (VIP)- and pituitary adenylate cyclase-activating polypeptide (PACAP)-induced relaxations of the pig intravesical ureter were investigated. 2. VIP, PACAP 38 and PACAP 27 concentration-dependently relaxed U46619-contracted ureteral strips with a similar potency. [Ala(11,22,28)]-VIP, a VPAC(1) agonist, showed inconsistent relaxations. 3. The neuronal voltage-gated Ca(2+) channel inhibitor, omega-conotoxin GVIA (omega-CgTX, 1 microm), reduced the VIP relaxations. Urothelium removal or blockade of capsaicin-sensitive primary afferents, nitric oxide (NO) synthase and guanylate cyclase with capsaicin (10 microm), N(G)-nitro-l-arginine (l-NOARG, 100 microm) and 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 5 microm), respectively, did not change the VIP relaxations. However, the PACAP 38 relaxations were reduced by omega-CgTX, capsaicin, l-NOARG and ODQ. 4. The VIP and VIP/PACAP receptor antagonists, [Lys(1), Pro(2,5), Arg(3,4), Tyr(6)]-VIP (1 microm) and PACAP (6-38) (0.4 microm), inhibited VIP and VIP and PACAP 38, respectively, relaxations. 5. The nonselective and large-conductance Ca(2)-activated K(+) channel blockers, tetraethylammonium (3 mm) and charybdotoxin (0.1 microm), respectively, and neuropeptide Y (0.1 microm) did not modify the VIP relaxations. The small-conductance Ca(2)-activated K(+) channel blocker apamin (1 microm) did not change the PACAP 27 relaxations. 6. The cAMP-dependent protein kinase A (PKA) blocker, 8-(4-chlorophenylthio)adenosine-3',5'-cyclic monophosphorothioate (Rp-8-CPT-cAMPS, 100 microm), reduced VIP relaxations. The phosphodiesterase 4 inhibitor rolipram and the adenylate cyclase activator forskolin relaxed ureteral preparations. The rolipram relaxations were reduced by Rp-8-CPT-cAMPS. Forskolin (30 nm) evoked a potentiation of VIP relaxations. 7. These results suggest that VIP and PACAP relax the pig ureter through smooth muscle receptors, probably of the VPAC(2) subtype, linked to a cAMP-PKA pathway. Neuronal VPAC receptors localized at motor nerves and PAC(1) receptors placed at sensory nerves and coupled to NO release, seem also to be involved in the VIP and PACAP 38 relaxations.
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PMID:Heterogeneity of neuronal and smooth muscle receptors involved in the VIP- and PACAP-induced relaxations of the pig intravesical ureter. 1466 37

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables has been retrieved from the Clinical Studies Knowledge Area of Prous Science Integrity(R), the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: Activated protein C concentrate, Ad-CD154, Adeno-Interferon gamma, alemtuzumab, APC-8024, 9-aminocamptothecin, aprepitant, l-arginine hydrochloride, aripiprazole, arsenic trioxide, asimadoline; O6-Benzylguanine, bevacizumab, Bi-20, binodenoson, biphasic insulin aspart, bivatuzumab, 186Re-bivatuzumab, BMS-181176, bosentan, botulinum toxin type B, BQ-123, bryostatin 1; Carboxy- amidotriazole, caspofungin acetate, CB-1954, CC-4047, CDP-860, cerivastatin sodium, clevidipine, CTL-102; 3,4-DAP, darbepoetin alfa, decitabine, desloratadine, DHA-paclitaxel, duloxetine hydrochloride; Efalizumab, EGF vaccine, eletriptan, eniluracil, ENMD-0997, eplerenone, eplivanserin, erlosamide, ertapenem sodium, escitalopram oxalate, esomeprazole magnesium, eszopiclone, everolimus, exatecan mesilate, exenatide, ezetimibe; Fondaparinux sodium, FR-901228, FTY-720; Gefitinib, gemtuzumab ozogamicin, gepirone hydrochloride; Hexyl insulin M2, human insulin; Imatinib mesylate, insulin detemir, insulin glargine, iodine (I131) tositumomab, ISV-205, ivabradine hydrochloride, ixabepilone; Levetiracetam, levocetirizine, linezolid, liposomal NDDP, lonafarnib, lopinavir, LY-156735; Mafosfamide cyclohexylamine salt, magnesium sulfate, maxacalcitol, meclinertant, melagatran, melatonin, MENT, mepolizumab, micafungin sodium, midostaurin, motexafin gadolinium; Nesiritide, NS-1209, NSC-601316, NSC-683864; Osanetant; Palonosetron hydrochloride, parecoxib sodium, pegaptanib sodium, peginterferon alfa-2a, peginterferon alfa-2b, pegylated OB protein, pemetrexed disodium, perillyl alcohol, picoplatin, pimecrolimus, pixantrone maleate, plevitrexed, polyglutamate paclitaxel, posurdex, pramlintide acetate, prasterone, pregabalin; Rasburicase, rimonabant hydrochloride, rostaporfin, rosuvastatin calcium; SDZ-SID-791, sibrotuzumab, sorafenib, SU-11248; Tadalafil, targinine, tegaserod maleate, telithromycin, TheraCIM, tigecycline, tiotropium bromide, tipifarnib, tirapazamine, treprostinil sodium; Valdecoxib, Valganciclovir hydrochloride, Vardenafil hydrochloride hydrate; Ximelagatran; Zofenopril calcium, Zoledronic acid monohydrate.
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PMID:Gateways to clinical trials. 1507 12

Resistance to the anticoagulant action of activated protein C, APC resistance, is a highly prevalent risk factor for venous thrombosis among individuals of Caucasian origin. In most cases, APC resistance is associated with a single missense mutation in the gene for coagulation factor V (FV (Leiden)), which predicts the replacement of Arg (506) with a Gln at one of the cleavage sites for APC in factor V. Factor V is a Janus-faced protein with dual functions, serving as an essential nonenzymatic cofactor in both pro- and anticoagulant pathways. Procoagulant factor Va, generated after proteolysis by thrombin or factor Xa, is a cofactor to factor Xa in the activation of prothrombin, whereas anticoagulant factor V, generated after proteolysis by APC, functions as a cofactor in the APC-mediated degradation of FVIIIa. The FV (Leiden) mutation affects the anticoagulant response to APC at two distinct levels of the coagulation pathway, as it impairs degradation of both activated factor V and activated factor VIII, the latter effect inasmuch as FVLeiden is a poor APC cofactor. Several other genetic traits, some of them quite common, are known to affect the anticoagulant response to APC, but none of them cause the same severe APC-resistance phenotype as FV (Leiden) and their importance as risk factors for thrombosis is unclear. A poor APC response may also result from acquired conditions, some of which are clearly involved in the pathogenesis of venous thrombosis. Venous thrombosis is a typical multifactorial disease, the pathogenesis of which involves multiple gene-gene and gene-environment interactions. In many patients with severe thrombophilia, APC resistance is found as a contributing risk factor.
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PMID:Congenital and acquired activated protein C resistance. 1519 91

1. Conflicting data have been reported on the contribution of nitric oxide (NO) to inhibitory neurotransmission in rat jejunum. Therefore, the mechanism of relaxation and contribution to inhibitory neurotransmission of NO, adenosine 5'-triphosphate (ATP), vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) was examined in the circular muscle of Wistar-Han rat jejunum. 2. Mucosa-free circular muscle strips were precontracted with methacholine in the presence of guanethidine and exposed to electrical field stimulation (EFS) and exogenous NO, ATP, VIP and PACAP. All stimuli induced reduction of tone and inhibition of phasic motility. Only electrically induced responses were sensitive to tetrodotoxin (3 x 10(-6) m). 3. NO (10(-6)-10(-4) m)-induced concentration-dependent relaxations that were inhibited by the soluble guanylyl cyclase inhibitor 1H-[1,2,4]-oxadiazolo-[4,3-a]-quinoxalin-1-one (ODQ; 10(-5) m) and the small conductance Ca(2+)-activated K(+)-channel blocker apamin (APA; 3 x 10(-8) m). 4. Relaxations elicited by exogenous ATP (10(-4)-10(-3) m) were inhibited by the P2Y purinoceptor antagonist reactive blue 2 (RB2; 3 x 10(-4) m), but not by APA and ODQ. 5. The inhibitory responses evoked by 10(-7) m VIP and 3 x 10(-8) m PACAP were decreased by the selective PAC(1) receptor antagonist PACAP(6-38) (3 x 10(-6) m) and APA. The VPAC(2) receptor antagonist PG99-465 (3 x 10(-7) m) reduced relaxations caused by VIP, but not those by PACAP, while the VPAC(1) receptor antagonist PG97-269 (3 x 10(-7) m) had no influence. 6. EFS-induced relaxations were inhibited by the NO-synthase inhibitor N(omega)-nitro-l-arginine methyl ester (3 x 10(-4) m), ODQ and APA, but not by RB2, PG97-269, PG99-465 and PACAP(6-38). 7. These results suggest that NO is the main inhibitory neurotransmitter in the circular muscle of Wistar-Han rat jejunum acting through a rise in cyclic guanosine monophosphate levels and activation of small conductance Ca(2+)-dependent K(+) channels.
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PMID:Inhibitory pathways in the circular muscle of rat jejunum. 1530 84

Tumor affects myelopoiesis by inhibiting the process of differentiation/maturation of antigen-presenting cells from their myeloid precursors and by stimulating an accumulation of immature myeloid cells in cancer patients and tumor-bearing mice. These immature myeloid cells can contribute greatly to tumor progression and promote tumor evasion from immune attack: i) by inhibiting development of adaptive immune responses against tumor in lymphoid organs; ii) by migrating into tumor site and differentiating there into highly immune suppressive tumor-associated macrophages. Immature myeloid cells and tumor-associated macrophages utilize different JAK/STAT signaling pathways and different mechanisms to control T cell responses, which include increased production of TGF-beta, reactive oxygen species, peroxynitrites, as well as enhanced L-arginine metabolism. Understanding of precise mechanisms, which tumors use to affect differentiation of APC from myeloid cell precursors and inhibit T cell responses, could help to develop new approaches for cancer therapy and substantially improve efficiency of existing cancer vaccination strategies.
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PMID:Role of immature myeloid cells in mechanisms of immune evasion in cancer. 1604 43

CDC4/FBXW7 is part of a ubiquitin ligase complex which targets molecules such as cyclin E, c-myc, and c-jun for destruction. CDC4 mutations occur in several cancer types and are best described in colorectal tumors. Knockout of CDC4 in vitro in colorectal cancer cells causes changes suggestive of chromosomal instability (CIN). In p53(+/-) mice, radiation-induced lymphomas show deletion or mutation of one copy of CDC4 and knockdown of CDC4 leads to increased aneuploidy in mouse fibroblasts. We screened 244 colorectal tumors and 40 cell lines for CDC4 mutations and allelic loss. Six percent (18 of 284) of tumors, including near-diploid (CIN-) lesions, harbored CDC4 mutations and there was no association between mutation and CIN (polyploidy). The CDC4 mutation spectrum in colorectal tumors was heavily biased towards C:G > T:A changes, either missense mutations at critical arginine residues or nonsense changes in the 5' half of the gene. The reasons for this odd mutation spectrum were unclear but C:G > T:A changes were not found more often than expected at APC, K-ras, or p53 in the same tumors and we found no specific defects in DNA repair to account for the observations. No colorectal tumor was found to carry two CDC4 mutations predicted to abolish protein function; partial loss of CDC4 function may therefore cause tumorigenesis. The in vitro studies, therefore, did not assess the functional effects of mutant alleles which are found in vivo. CDC4 mutations may be selected primarily to drive progression through the cell cycle although CIN might be an important secondary effect in some cancers.
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PMID:CDC4 mutations occur in a subset of colorectal cancers but are not predicted to cause loss of function and are not associated with chromosomal instability. 1635 43

APC (activated Protein C) inactivates human Factor VIIIa following cleavage at residues Arg336 and Arg562 within the A1 and A2 subunits respectively. The role of the P1 arginine in APC-catalysed inactivation of Factor VIIIa was examined by employing recombinant Factor VIIIa molecules where residues 336 and 562 were replaced with alanine and/or glutamine. Stably expressed Factor VIII proteins were activated by thrombin and resultant Factor VIIIa was reacted at high concentration with APC to minimize cofactor inactivation due to A2 subunit dissociation. APC cleaved wild-type Factor VIIIa at the A1 site with a rate approximately 25-fold greater than that for the A2 site. A1 mutants R336A and R336Q were inactivated approximately 9-fold slower than wild-type Factor VIIIa, whereas the A2 mutant R562A was inactivated approximately 2-fold slower. No cleavage at the mutated sites was observed. Taken together, these results suggested that cleavage at the A1 site was the dominant mechanism for Factor VIIIa inactivation catalysed by the proteinase. On the basis of cleavage at Arg336, a K(m) value for wild-type Factor VIIIa of 102 nM was determined, and this value was significantly greater than K(i) values (approximately 9-18 nM) obtained for an R336Q/R562Q Factor VIIIa. Furthermore, evaluation of a series of cluster mutants in the C-terminal region of the A1 subunit revealed a role for acidic residues in segment 341-345 in the APC-catalysed proteolysis of Arg336. Thus, while P1 residues contribute to catalytic efficiency, residues removed from these sites make a primary contribution to the overall binding of APC to Factor VIIIa.
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PMID:Role of P1 residues Arg336 and Arg562 in the activated-Protein-C-catalysed inactivation of Factor VIIIa. 1650 79


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