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Structural requirements of MLD-containing disintegrins for functional interaction with alpha 4 beta 1 and alpha 9 beta1 integrins 总被引:1,自引:0,他引:1
Bazan-Socha S Kisiel DG Young B Theakston RD Calvete JJ Sheppard D Marcinkiewicz C 《Biochemistry》2004,43(6):1639-1647
Three non-RGD-containing disintegrins, VLO5, EO5, and EC3, belong to the heterodimeric family of these snake venom-derived proteins. They are potent inhibitors of certain leukocyte integrins such as alpha4beta1, alpha4beta7, and alpha9beta1, and act through the MLD motif present in one of their subunits. However, the selectivity of these disintegrins to interact with integrins is related to the amino acid composition of the integrin-binding loop in the MLD-containing subunit. The most important amino acid is that preceding the MLD motif. In vitro experiments in adhesion and ELISA assays revealed that the TMLD-containing disintegrins, VLO5 and EO5, appeared to be very potent inhibitors of human alpha4beta1 and alpha9beta1 and less effective in inhibition of the alpha4beta7 integrin. The reverse effect was observed for the AMLD-containing disintegrin, EC3. The data with native disintegrins were confirmed by experiments with synthetic peptides displaying TMLD and AMLD motifs. The MLD-containing disintegrins showed differential activities to inhibit human and murine alpha4beta1 integrin. EC3 was a weaker inhibitor of human integrin, whereas VLO5 and EO5 less actively inhibited murine alpha4beta1. These data describe a useful set of potent and selective integrin antagonists and suggest conformational requirements of human and mouse integrins for interaction with ligands. 相似文献
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Effects of sub-zero temperatures (−5 to −35°C) on the tissues of needles, buds and shoots of Norway spruce [ Picea abies (L.) Karst.] were studied. The freezing caused increased efflux of cellular electrolytes. Freezing injury of the primordial shoots and 1-year-old shoots was the result of the spontaneous freezing of a deep supercooled cellular water. The crystallization injures the cellular membranes leading to the loss of semipermeability and to the drastic efflux of K+ . In the needles there was no deep supercooling of water and two patterns of changes in the membranes, depending upon the range of the applied temperatures, could be distinguished. At 0 to – 25°C, which do not kill the cells, we observed a disturbance in the membrane semipermeability as monitored by electrolytes efflux within a few hours after thawing of the needles. At lower temperatures (−35°C) we observed irreversible loss of the membrane semipermeability, and death of the tissue. Those changes occurred 10 h after thawing and were probably caused by the released lytic enzymes and some toxic compounds, which acted on the cellular membranes. 相似文献
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Ari Elson Christine A. Kozak Cynthia C. Morton Stanislawa Weremowicz Philip Leder 《Genomics》1996,31(3):373
We have mapped the mouse protein tyrosine phosphatase ? (PTP?, gene symbolPtpre) gene to the distal region of chromosome 7 by linkage analysis using two sets of multilocus genetic crosses. The humanPTP? gene (gene symbolPTPRE) was mapped to chromosome 10q26 by fluorescencein situhybridization. We have previously documented the existence of two isoforms ofPTP?—a transmembranal, receptor-type isoform and a shorter, cytoplasmic one. Both isoforms have been suggested to arise from a single gene through the use of alternative promoters and 5′ exons. The identification of a singlePTP? locus in both organisms is consistent with this suggestion. 相似文献
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The seeds of pedunculate oak (Quercus robur L.) were subjected to slow (S) and rapid (R) desiccation at desiccation rates of 0.16 and 0.39% H2O per hour, respectively. Till ca. 40% water content (WC) the germination capacity of seeds in the S and R variants was high
(ca. 100%). Between 40 and 28% WC, germination capacity declined to 20 and 50% in S and R variants, respectively. The decrease
in seed viability was accompanied by a significant increase of electrolyte leakage from embryonic axes (28% for S and 15%
for R variants). In the embryonic axes of seeds subjected to slow desiccation, malondialdehyde (MDA) and free fatty acid (FFA)
contents were significantly higher than those in R variants, indicating greater membrane damage due to lipid peroxidation.
The production of ROS (H2O2 and O2·−) was significantly higher in S than in R variants. The low molecular weight antioxidants α-tocopherol, ascorbic acid (ASA),
and phenolic compounds indicated different reactions in response to desiccation stress. ASA levels decreased during desiccation
to a similar degree in both the S and R variants. A significant decrease of total phenols was observed in R variant, which
coincided with a significant increase of guaiacol peroxidase (POX) activity. α-Tocopherol content was significantly higher
in the embryonic axes of seeds subjected to rapid drying. The activities of the enzymatic scavengers APX and GR had similar
runs and were slightly higher in R variant. The activities of POX and SOD were significantly higher in the embryonic axes
of seeds subjected to rapid drying. These results show that rapid dehydration of Q. robur seeds leads to the greater mobilization of antioxidant system in embryonic axes, particularly increased levels of α-tocopherol
and POX and SOD activities, in the first stages of water loss. This mobilization has a greater impact on maintenance of higher
viability of seeds after drying to lower level of WC. 相似文献
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Polycystin-1 and polycystin-2 are the products of PKD1 and PKD2, genes that are mutated in most cases of autosomal dominant polycystic kidney disease. Since the first two polycystins were cloned, three new members, polycystin-L, -2L2, and -REJ, have been identified. In this study, we describe a sixth member of the family, polycystin-1L1, encoded by PKD1L1 in human. The full-length cDNA sequence of PKD1L1, determined from human testis cDNA, encodes a 2849-amino-acid protein and 58 exons in a 187-kb genomic region. The deduced amino acid sequence of polycystin-1L1 has significant homology with all known polycystins, but the longest stretches of homology were found with polycystin-1 and -REJ over the 1453- and 932-amino-acid residues, respectively. Polycystin-1L1 is predicted to have two Ig-like PKD, a REJ, a GPS, a LH2/PLAT, a coiled-coil, and 11 putative transmembrane domains. Several rhodopsin-like G-protein-coupled receptor (GPCR) signatures are also found in polycystin-1L1. Dot-blot analysis and RT-PCR revealed that human PKD1L1 is expressed in testis and in fetal and adult heart. In situ hybridization analysis showed that the most abundant and specific expression of Pkd1l1 was found in Leydig cells, a known source of testosterone production, in mouse testis. We have assigned PKD1L1 to the short arm of human chromosome 7 in bands p12--p13 and Pkd1l1 to mouse chromosome 11 in band A2 by fluorescence in situ hybridization. We hypothesize a role for polycystin-1L1 in the heart and in the male reproductive system. 相似文献
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Boehm JS Zhao JJ Yao J Kim SY Firestein R Dunn IF Sjostrom SK Garraway LA Weremowicz S Richardson AL Greulich H Stewart CJ Mulvey LA Shen RR Ambrogio L Hirozane-Kishikawa T Hill DE Vidal M Meyerson M Grenier JK Hinkle G Root DE Roberts TM Lander ES Polyak K Hahn WC 《Cell》2007,129(6):1065-1079
The karyotypic chaos exhibited by human epithelial cancers complicates efforts to identify mutations critical for malignant transformation. Here we integrate complementary genomic approaches to identify human oncogenes. We show that activation of the ERK and phosphatidylinositol 3-kinase (PI3K) signaling pathways cooperate to transform human cells. Using a library of activated kinases, we identify several kinases that replace PI3K signaling and render cells tumorigenic. Whole genome structural analyses reveal that one of these kinases, IKBKE (IKKepsilon), is amplified and overexpressed in breast cancer cell lines and patient-derived tumors. Suppression of IKKepsilon expression in breast cancer cell lines that harbor IKBKE amplifications induces cell death. IKKepsilon activates the nuclear factor-kappaB (NF-kappaB) pathway in both cell lines and breast cancers. These observations suggest a mechanism for NF-kappaB activation in breast cancer, implicate the NF-kappaB pathway as a downstream mediator of PI3K, and provide a framework for integrated genomic approaches in oncogene discovery. 相似文献
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Purification of the human NF-E2 complex: cDNA cloning of the hematopoietic cell-specific subunit and evidence for an associated partner. 总被引:12,自引:4,他引:8
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P A Ney N C Andrews S M Jane B Safer M E Purucker S Weremowicz C C Morton S C Goff S H Orkin A W Nienhuis 《Molecular and cellular biology》1993,13(9):5604-5612
The human globin locus control region-binding protein, NF-E2, was purified by DNA affinity chromatography. Its tissue-specific component, p45 NF-E2, was cloned by use of a low-stringency library screen with murine p45 NF-E2 cDNA (N. C. Andrews, H. Erdjument-Bromage, M. B. Davidson, P. Tempst, and S. H. Orkin, Nature [London] 362:722-728, 1993). The human p45 NF-E2 gene was localized to chromosome 12q13 by fluorescent in situ hybridization. Human p45 NF-E2 and murine p45 NF-E2 are highly homologous basic region-leucine zipper (bZIP) proteins with identical DNA-binding domains. Immunoprecipitation experiments demonstrated that p45 NF-E2 is associated in vivo with an 18-kDa protein (p18). Because bZIP proteins bind DNA as dimers, we infer that native NF-E2 must be a heterodimer of 45- and 18-kDa subunits. Although AP-1 and CREB copurified with NF-E2, no evidence was found for heterodimer formation between p45 NF-E2 and proteins other than p18. Thus, p18 appears to be the sole specific partner of p45 NF-E2 in erythroid cells. Cloning of human p45 NF-E2 should permit studies of the role of NF-E2 in globin gene regulation and erythroid differentiation. 相似文献