| 7519807 |
Entry of coxsackievirus A9 into host cells: specific interactions with alpha v beta 3 integrin, the vitronectin receptor. |
10.1006/viro.1994.1494 |
Virology |
Entry of coxsackievirus A9 into host cells: specific interactions with alpha v beta 3 integrin, the vitronectin receptor.
Abstract
- Attachment and entry of coxsackievirus A9 (CAV-9) to GMK cells were previously shown to be dependent on an arginine-glycine-aspartic acid (RGD) motif in the capsid protein VP1, suggesting integrins as candidate receptors for the virus. We have pursued the matter further and show that antibodies specific for the alpha v and/or beta 3 integrin subunits protect GMK cells from CAV-9 infection. Affinity purification of radioiodinated cell surface proteins using CAV-9 or virus-specific peptide (RRRGDL) columns confirmed that the alpha v beta 3 heterodimer, known as the vitronectin receptor, is recognized by the virus in GMK cells. Other proteins, of lower molecular weight (less than 40 kDa), were also bound to and specifically eluted from the columns, but their possible role in attachment and entry of CAV-9 remains to be elucidated by further studies. Of several other related viruses studied, only echovirus 22, which also has an RGD motif in the VP1 capsid protein, was found to compete for cell surface binding with CAV-9.
|
| 7522304 |
Calcium signalling in T cells stimulated by a cyclophilin B-binding protein |
10.1038/371355a0. |
Nature |
Calcium signalling in T cells stimulated by a cyclophilin B-binding protein
Abstract
- The immunosuppressant drug cyclosporin A blocks a calcium-dependent signal from the T-cell receptor (TCR) that normally leads to T-cell activation. When bound to cyclophilin, cyclosporin A binds and inactivates the key signalling intermediate calcineurin. To identify potential cellular homologues of cyclosporin A that might regulate calcium signalling, we have cloned human genes encoding cyclophilin B-binding-proteins using the yeast two-hybrid system. One gene product, when overexpressed in Jurkat T cells, specifically induced transcription from the interleukin-2 enhancer, by activating the T-cell-specific transcription factors NF-AT and NF-IL2A. This protein, termed calcium-signal modulating cyclophilin ligand (CAML), acts downstream of the TCR and upstream of calcineurin by causing an influx of calcium. CAML appears to be a new participant in the calcium-signal transduction pathway, implicating cyclophilin B in calcium signalling, even in the absence of cyclosporin.
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| 7523555 |
Selective alpha IIb beta 3 receptor blockage with peptide TP9201 prevents platelet uptake on Dacron vascular grafts without significant effect on bleeding time |
None |
J Lab Clin Med |
Selective alpha IIb beta 3 receptor blockage with peptide TP9201 prevents platelet uptake on Dacron vascular grafts without significant effect on bleeding time
Abstract
- Synthetic vascular prostheses lack the uniquely low thrombogenicity provided by the endothelial cell lining of autogenous saphenous vein or artery grafts. The thrombogenic nature of the synthetic graft surface becomes a major determinant of early prosthetic graft patency. We demonstrate in a baboon ex vivo synthetic graft model that modification of the host's platelet interaction with the graft surface results in inhibition of platelet thrombus formation and thereby, a possible enhancement of early prosthetic graft patency. This was achieved by selective blockage of the platelet alpha IIb beta 3 receptor by the arginine-glycine-aspartic acid-containing synthetic peptide TP9201. Platelet thrombus formation on a Dacron graft indicated by accumulation of indium III-oxine-labeled autologous platelets was measured by gamma camera imaging. After 60 minutes of circulation, TP9201 at a bolus of 125 micrograms/kg; infusion of 3 micrograms/kg/min, bolus of 190 micrograms/kg; infusion of 5 micrograms/kg/min, bolus of 250 micrograms/kg; infusion of 6 micrograms/kg/min, and bolus of 500 micrograms/kg; infusion of 12 micrograms/kg/min decreased platelet uptake on the graft to 50%, 40%, 30%, and 10% of control uptake, respectively. Forelimb template bleeding times were not found to be significantly prolonged at doses that effectively inhibit ex vivo platelet aggregation. As a result of drug treatment, no changes in hemodynamic parameters or hematologic profile, including platelet number and clotting time, were observed. We demonstrate here that the arginine-glycine-aspartic acid-containing peptide TP9201, which competitively inhibits the alpha IIb beta 3 integrin-fibrinogen interaction, significantly decreased the accumulation of platelets on a Dacron vascular graft. Molecules like peptide TP9201, because of its unique activity profile, may represent a superior approach to the control of platelet accumulation on thrombogenic surfaces."
|
| 7528089 |
Twisted alpha-keto amides as transition-state analogues for acyl-transfer reactions: synthesis of the immunoconjugates |
10.1016/0968-0896(94)80022-7. |
Bioorg Med Chem |
Twisted alpha-keto amides as transition-state analogues for acyl-transfer reactions: synthesis of the immunoconjugates
Abstract
- Two new haptens were employed as antigens to elicit antibodies for acyl-transfer reactions. The haptens, both alpha-keto amides were designed to elicit antibodies which could twist potential substrates into a much more reactive conformation. The rationale for their design, synthesis, and immunization protocols will be discussed.
|
| 7528191 |
WIN 66306, a new neurokinin antagonist produced by an Aspergillus species: fermentation, isolation and physico-chemical properties |
10.7164/antibiotics.47.1182. |
J Antibiot (Tokyo) |
WIN 66306, a new neurokinin antagonist produced by an Aspergillus species: fermentation, isolation and physico-chemical properties
Abstract
- WIN 66306 (1a), a cyclic peptide containing a novel amino acid, was isolated as a neurokinin antagonist from an Aspergillus species, labelled SC230. Conditions that maximized the production of 1a were developed, leading also to production of the related compound WIN 68577 (2) and rosellichalasin (3). Both 2 and 3 were more active in the rat NK1 than in the human NK1 receptor binding assay, while 1a was more active at the human receptor with an inhibitor affinity constant of 7 microM.
|
| 7531879 |
Malformin A prevents IL-1 induced endothelial changes by inhibition of protein synthesis |
None |
Thromb Haemost |
Malformin A prevents IL-1 induced endothelial changes by inhibition of protein synthesis
Abstract
|
| 7535538 |
Use of the minimal function for partial structure development in direct methods |
10.1107/s0108767394006914. |
Acta Crystallogr A |
Use of the minimal function for partial structure development in direct methods
Abstract
- The shake-and-bake procedure, which is based on the minimal function, has been tested and shown to be extremely effective in molecular-fragment recycling applications. Correctly positioned fragments as small as 5% of the scattering power of the structure typically have a 50% chance of producing a solution in a single recycling trial. While starting models for tangent-formula recycling methods normally require an average r.m.s. displacement error of less than approximately 0.25 A from the refined structure to ensure an adequate chance of success, the shake-and-bake method often tolerates r.m.s. model errors well in excess of 0.5 A. Tests indicate that the new method can outperform traditional tangent-formula procedures in difficult structural applications involving multiple copies of pseudosymmetrically related molecules or low-resolution data.
|
| 7537837 |
Peptide-based tachykinin NK2 receptor antagonists |
10.1002/med.2610150205. |
Med Res Rev |
Peptide-based tachykinin NK2 receptor antagonists
Abstract
|
| 7537849 |
Phosphotyrosine-dependent interaction of SHC and insulin receptor substrate 1 with the NPEY motif of the insulin receptor via a novel non-SH2 domain |
10.1128/MCB.15.5.2500. |
Mol Cell Biol |
Phosphotyrosine-dependent interaction of SHC and insulin receptor substrate 1 with the NPEY motif of the insulin receptor via a novel non-SH2 domain
Abstract
- The SHC proteins have been implicated in insulin receptor (IR) signaling. In this study, we used the sensitive two-hybrid assay of protein-protein interaction to demonstrate that SHC interacts directly with the IR. The interaction is mediated by SHC amino acids 1 to 238 and is therefore independent of the Src homology 2 domain. The interaction is dependent upon IR autophosphorylation, since the interaction is eliminated by mutation of the IR ATP-binding site. In addition, mutational analysis of the Asn-Pro-Glu-Tyr (NPEY) motif within the juxtamembrane domain of the IR showed the importance of the Asn, Pro, and Tyr residues to both SHC and IR substrate 1 (IRS-1) binding. We conclude that SHC interacts directly with the IR and that phosphorylation of Tyr-960 within the IR juxtamembrane domain is necessary for efficient interaction. This interaction is highly reminiscent of that of IRS-1 with the IR, and we show that the SHC IR-binding domain can substitute for that of IRS-1 in yeast and COS cells. We identify a homologous region within the IR-binding domains of SHC and IRS-1, which we term the SAIN (SHC and IRS-1 NPXY-binding) domain, which may explain the basis of these interactions. The SAIN domain appears to represent a novel motif which is able to interact with autophosphorylated receptors such as the IR.
|
| 7538136 |
Tachykinin NK1 and NK2 receptors mediate the non-cholinergic bronchospastic response to capsaicin and vagal stimulation in guinea-pigs |
10.1111/j.1474-8673.1995.tb00347.x. |
J Auton Pharmacol |
Tachykinin NK1 and NK2 receptors mediate the non-cholinergic bronchospastic response to capsaicin and vagal stimulation in guinea-pigs
Abstract
- 1. The antibronchospastic activity against acetylcholine, capsaicin, electrical vagal stimulation and the selective tachykinin agonists (beta Ala8NKA-(4-10) and Sar9SP sulfone) of a novel NK2 receptor antagonist, MEN10,627 and/or the known NK1 receptor antagonist (+/-)-CP96,345 was studied in anaesthetized guinea-pigs. 2. MEN10,627 (0.1 mumol kg-1 i.v.) and (+/-)-CP96,345 (3 mumol kg-1 i.v.) selectively reduced the bronchospasm induced by NK2 and NK1 tachykinin receptor agonists, respectively, without affecting the other tachykinin receptor agonist- or acetylcholine-induced bronchospastic response. 3. MEN10,627 (0.1 mumol kg-1 i.v.), in a dose-dependent manner, reduced the non-cholinergic response induced by bilateral stimulation of the vagi or by intravenous capsaicin. 4. The administration of (+/-)-CP96,345 (3 mumol kg-1 i.v.) alone did not affect these responses but, when administered in association with the NK2 antagonist, (+/-)-CP96,345, was able to potentiate its inhibitory effect. 5. It is concluded that both NK1 and NK2 receptors are involved in the non-cholinergic bronchoconstriction induced by capsaicin or by stimulation of the vagi, although the NK2 receptor contribution is prominent.
|
| 7538143 |
Two mutations in the insulin receptor gene of a patient with leprechaunism: application to prenatal diagnosis |
10.1210/jcem.80.5.7538143. |
J Clin Endocrinol Metab |
Two mutations in the insulin receptor gene of a patient with leprechaunism: application to prenatal diagnosis
Abstract
- Leprechaunism is an autosomal recessive disorder caused by mutations in the insulin receptor gene and characterized by intrauterine and postnatal growth restriction, abnormal glucose homeostasis, and severe insulin-resistance. Here we report the biochemical and molecular characterization of a male patient, NZ, who died at 2 yr of age with this syndrome. 125I-Insulin binding to fibroblasts from the proband, his mother, father, and unaffected sister was reduced to 8, 53, 38, and 35% of controls, respectively. Analysis of the insulin receptor gene by polymerase chain reaction amplification using primers flanking each of the 22 exons and direct DNA sequencing identified 2 different mutations in the proband. The paternal mutation was an in-frame deletion of base pairs 1159-1161 in exon 3, which resulted in the loss of the codon for Asn-281. The maternal mutation was a G-->A transition in the first nucleotide of the splice-donor junction in intron 13. The maternal mutation activated a cryptic splice site 27 base pairs upstream in exon 13 and caused an in-frame deletion of amino acids 859-867 of the extracellular domain of the insulin receptor beta subunit. Identification of both mutations enabled prenatal diagnosis in 2 subsequent pregnancies. In the first pregnancy, DNA from cells cultured from chorionic villus (CV) biopsies carried both mutations in the insulin receptor gene. In the second pregnancy, DNA from the CV biopsy cells was negative for both mutations, indicating that the fetus was unaffected by leprechaunism. Insulin binding could not be used in prenatal diagnosis because cells cultured from some control CV biopsies failed to bind insulin. These data indicate that patient NZ with leprechaunism was a compound heterozygote for 2 novel mutations in the insulin receptor gene and that direct DNA sequencing enables prenatal diagnosis for this lethal disorder.
|
| 7539864 |
Tachykinin effects on bladder activity in conscious normal rats |
None |
J Urol |
Tachykinin effects on bladder activity in conscious normal rats
Abstract
- When instilled intravesically in normal, unanesthetized rats, neurokinin A (NKA), but not substance P (SP) and neurokinin B (NKB), stimulated micturition. The effect of NKA was inhibited by the NK2 receptor selective antagonists SR 48,968 and MEN 10,627, but not by the NK1 receptor selective antagonist RP 67,580, suggesting that the effect was mediated by stimulation of NK2 receptors. Given intra-arterially near the bladder, NKA produced an increase in basal intravesical pressure before initiating micturition, indicating that the tachykinin had a direct contractant effect on the detrusor smooth muscle. Such a contractile effect was not observed when NKA was given intravesically. The effect of intra-arterial NKA could not be blocked by the NK1 receptor selective antagonist SR 140,333 or the NK2 receptor selective antagonist SR 48,968, but by their combination. Also intra-arterial NKB stimulated micturition, but was less potent than NKA. Intra-arterial SP had only weak stimulating effects. The results suggest that intravesically administered NKA can initiate micturition in the normal rat by stimulation of superficially located NK2 receptors in the urothelium. Intra-arterially administered NKA caused bladder hyperactivity via stimulation of both NK1 and NK2 receptors.
|
| 7541045 |
Non-SH2 domains within insulin receptor substrate-1 and SHC mediate their phosphotyrosine-dependent interaction with the NPEY motif of the insulin- like growth factor I receptor. |
10.1074/jbc.270.26.15639 |
J. Biol. Chem. |
Non-SH2 domains within insulin receptor substrate-1 and SHC mediate their phosphotyrosine-dependent interaction with the NPEY motif of the insulin- like growth factor I receptor.
Abstract
- Insulin receptor substrate-1 (IRS-1) and SHC become rapidly phosphorylated upon tyrosines after insulin-like growth factor I receptor (IGFIR) activation. In this study we demonstrate that IRS-1, SHC, and the p85 subunit of phosphatidylinositol 3-kinase interact directly and specifically with the IGFIR. The interaction of all three proteins is dependent upon IGFIR kinase activity and, furthermore, substitution of Tyr-950 with Phe within the NPEY motif of the IGFIR eliminated interaction with both SHC and IRS-1 but had no effect upon p85 interaction. We show that residues 160-516 of IRS-1 and 1-238 of SHC are sufficient and necessary for receptor interaction in the yeast two-hybrid assay. We also demonstrate a direct in vitro interaction between the IGFIR and a fusion protein containing SHC amino acids 1-238. No interaction was observed with a SHC protein containing only the SH2 domain. We conclude that SHC and IRS-1 interact with the tyrosine-phosphorylated NPEY motif of the IGFIR, and that both proteins interact via related motifs located in their amino termini. We conclude that the interactions of SHC and IRS-1 with the IGFIR are similar to those which we have previously defined with the insulin receptor.
|
| 7545517 |
Evidence that tachykinin NK1 and NK2 receptors mediate non-adrenergic non-cholinergic excitation and contraction in the circular muscle of guinea-pig duodenum |
10.1111/j.1476-5381.1995.tb15869.x. |
Br J Pharmacol |
Evidence that tachykinin NK1 and NK2 receptors mediate non-adrenergic non-cholinergic excitation and contraction in the circular muscle of guinea-pig duodenum
Abstract
- 1. In the presence of atropine (1 microM), guanethidine (3 microM), indomethacin (3 microM), apamin (0.1 microM) and L-nitroarginine (L-NOARG, 30 microM), electrical field simulation (EFS) produced a nonadrenergic, noncholinergic (NANC) excitatory junctional potential (e.j.p.), action potentials and contraction of the circular muscle of the guinea-pig proximal duodenum, recorded by the single sucrose gap technique. 2. The selective tachykinin (TK) NK1 receptor antagonist, GR 82,334 (30 nM-3 microM) produced a concentration-dependent inhibition of the EFS-evoked NANC e.j.p. and contraction. Similarly, the selective NK2 receptor antagonists, MEN 10,627 (30 nM-3 microM) and GR 94,800 (100 nM-10 microM), both produced a concentration-dependent inhibition of the EFS-evoked NANC e.j.p. and contraction. GR 82,334 inhibited the electrical and mechanical NANC responses to EFS in an almost parallel manner, while MEN 10,627 and GR 94,800 were more effective in inhibiting the mechanical than the electrical response to EFS. 3. Activation of the NK1 or NK2 receptor by the selective agonists, Sar9substance P (SP) sulphone and beta Ala8neurokinin A (NKA) (4-10), respectively (0.3 microM each), produced depolarization, action potentials and contractions. GR 82,334 selectively inhibited the responses to Sar9SP sulphone, without affecting the responses to beta Ala8NKA (4-10). MEN 10,627 and GR 94,800 inhibited or abolished the responses to beta Ala8NKA (4-10), without affecting the responses to Sar9SP sulphone. 4. Nifedipine (1 microM) abolished the action potentials and contraction produced either by EFS or by the TK receptor agonists Sar9SP sulphone or beta Ala8NKA (4-10). 5. In the presence of nifedipine, the NANC e.j.p. produced by EFS was biphasic: in the majority of strips tested (21 out of 29) an early fast phase of depolarization was followed by a second slow component. The combined administration of GR 82,334 and GR 94,800 (3 microM each) reduced both components, the slow phase being inhibited to a greater extent than the fast phase. 6. The P2 purinoreceptor antagonist, suramin (100 microM) reduced the fast phase of the e.j.p. produced by EFS in the presence of nifedipine, without affecting the slow phase. The combined administration of suramin, GR 82,334 and GR 94,800 produced a nearly complete blockade of the e.j.p. produced by EFS in the presence of nifedipine. 7. When tested in the absence of apamin and L-NOARG, EFS induced a NANC inhibitory junction potential (i.j.p.) followed by an e.j.p., and the selective P2Y receptor agonist, adenosine-5'-O-(2-thiodiphosphate) (ADP beta S, 10 microM), produced membrane hyperpolarization. After addition of apamin and L-NOARG, the ij.p. was blocked, and EFS produced a pure NANC e.j.p.; ADPPS produced depolarization, action potentials and contraction.8. Suramin (100 microM) blocked the depolarization, action potentials and contractions produced by ADP beta S in the presence of apamin and L-NOARG, without affecting the responses produced by the NK1receptor agonist, Sar9}SP sulphone.9. We conclude that NK1 and NK2 receptors cooperate in producing NANC excitation and contraction of the circular muscle in the guinea-pig proximal duodenum. Activation of either TK receptor produces membrane depolarization and both receptors contribute to generate action potentials which are essential for producing muscle contraction, via nifedipine-sensitive calcium channels. It appears that endogenous ATP chiefly acts as an inhibitory transmitter but, after blockade of NANC inhibitory mechanism(s),ATP may act as a fast signalling excitatory transmitter."
|
| 7545944 |
Human ribosomal protein L37 has motifs predicting serine/threonine phosphorylation and a zinc-finger domain |
10.1016/0167-4781(94)90197-x. |
Biochim Biophys Acta |
Human ribosomal protein L37 has motifs predicting serine/threonine phosphorylation and a zinc-finger domain
Abstract
- Ribosomal protein L37 mRNA is overexpressed in colon cancer. The nucleotide sequences of human L37 from several tumor and normal, colon and liver cDNA sources were determined to be identical. L37 mRNA was approximately 375 nucleotides long encoding 97 amino acids with M(r) = 11,070, pI = 12.6, multiple potential serine/threonine phosphorylation sites and a zinc-finger domain. The human sequence is compared to other species.
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