Science's STKEPub Date : 2002-04-16DOI: 10.1038/NEWS020624-1
Philip Ball
{"title":"Going Against the Flow","authors":"Philip Ball","doi":"10.1038/NEWS020624-1","DOIUrl":"https://doi.org/10.1038/NEWS020624-1","url":null,"abstract":"","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"15 1","pages":"tw144 - tw144"},"PeriodicalIF":0.0,"publicationDate":"2002-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84901738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-03-26DOI: 10.1126/scisignal.1252002tw121
{"title":"Neuronal Plasticity Promoted by Glia","authors":"","doi":"10.1126/scisignal.1252002tw121","DOIUrl":"https://doi.org/10.1126/scisignal.1252002tw121","url":null,"abstract":"Tumor necrosis factor-α (TNF-α), otherwise known as a proinflammatory cytokine, turns out to be active on a continual basis in the nervous system. Beattie et al., studied synaptic function in cultured hippocampal neurons and hippocampal brain slices and showed that TNF-α promotes expression of a neurotransmitter receptor on the cell surfaces at synapses. TNF-α is required continuously, suggesting that it may contribute to rapid adjustment of receptor levels at a synapse. TNF-α is supplied by affiliated glial cells, once again reminding us that the glial cells, previously thought to be rather passive support partners, are important behind-the-scenes participants in neuronal function. E. C. Beattie, D. Stellwagen, W. Morishita, J. C. Bresnahan, B. K. Ha, M.Von Zastrow, M. S. Beattie, R. C. Malenka, Control of synaptic strength by glial TNF-α. Science 295, 2282-2285 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"44 5","pages":"tw121 - tw121"},"PeriodicalIF":0.0,"publicationDate":"2002-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91552266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-03-26DOI: 10.1126/scisignal.1252002tw122
{"title":"Presynaptic Calcium Influx","authors":"","doi":"10.1126/scisignal.1252002tw122","DOIUrl":"https://doi.org/10.1126/scisignal.1252002tw122","url":null,"abstract":"Neurotransmitter release is triggered by calcium influx through presynaptic voltage-dependent calcium channels. Modulation of presynaptic calcium currents causes a robust alteration in synaptic efficacy. Tsujimoto et al. investigated activity-dependent facilitation of P/Q-type calcium currents at the giant nerve terminals of the calyx of Held and found that calcium current up-regulation is mediated by the calcium-binding protein NCS-1, a homolog of the Drosophila frequenin protein. T. Tsujimoto, A. Jeromin, N. Saitoh, J. C. Roder, T. Takahashi, Neuronal calcium sensor 1 and activity-dependent facilitation of P/Q-type calcium current at presynaptic nerve terminals. Science 295: 2276-2279 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"13 1","pages":"tw122 - tw122"},"PeriodicalIF":0.0,"publicationDate":"2002-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82059737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-03-19DOI: 10.1126/scisignal.1242002tw111
{"title":"Akt-ing Against a Loss","authors":"","doi":"10.1126/scisignal.1242002tw111","DOIUrl":"https://doi.org/10.1126/scisignal.1242002tw111","url":null,"abstract":"Mutations in the tumor suppressor protein PTEN occur in a variety of cancers. Its major enzymatic activity is to dephosphorylate phosphoinositides, including phosphoinositide-3,4,5-trisphosphate (PIP3). In the absence of PTEN, cellular levels of PIP3 increase, which result in overgrowth phenotypes and lethality in Drosophila larvae. However, PIP3 binds to numerous signaling molecules, and so it is not clear if there is a specific interaction that loss of PTEN function primarily affects. Stocker et al. show that flies can live in the absence of PTEN if the interaction of PIP3 with the serine-threonine kinase Akt is decreased through a mutation in its PH domain. At least in the fly, Akt appears to be the principal target of PIP3. H. Stocker, M. Andjelkovic, S. Oldham, M. Laffargue, M. P. Wymann, B. A. Hemmings, E. Hafen, Living with lethal PIP3 levels: Viability of flies lacking PTEN restored by a PH domain mutation in Akt/PKB. Science 295, 2088-2091 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"3 1","pages":"tw111 - tw111"},"PeriodicalIF":0.0,"publicationDate":"2002-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90928245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-03-12DOI: 10.1126/scisignal.1232002tw103
{"title":"A Sense of Cell","authors":"","doi":"10.1126/scisignal.1232002tw103","DOIUrl":"https://doi.org/10.1126/scisignal.1232002tw103","url":null,"abstract":"The transcription factor CtBP associates with transcriptional repressors for the regulation of genes involved in development, cell cycle regulation, and transformation. Zhang et al. show that the corepressor activity of CtBP can be regulated by the redox state of the cell. Mammalian CtBP is regulated by physiological concentrations of nuclear nicotinamide adenine dinucleotides (NADs). When the nuclear concentration of free NAD and NADH increases, CtBP increases its affinity for viral and cellular repressors and represses transcription. This regulatory mechanism suggests how protein interactions might respond to metabolic balances for the regulation of transcription. Q. Zhang, D. W. Piston, R. H. Goodman, Regulation of corepressor function by nuclear NADH. Science 295, 1895-1897 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"72 1","pages":"tw103 - tw103"},"PeriodicalIF":0.0,"publicationDate":"2002-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83241532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-03-12DOI: 10.1126/scisignal.1232002tw105
{"title":"Dose-Dependent Responses to Calcium","authors":"","doi":"10.1126/scisignal.1232002tw105","DOIUrl":"https://doi.org/10.1126/scisignal.1232002tw105","url":null,"abstract":"Dynamic changes in signaling mechanisms may encode specific information critical to cellular regulation. Deciphering these messages requires sophisticated measurements of key signaling molecules in living cells. Teruel and Meyer present a method that allows measurement of calcium-dependent translocation of fluorescently tagged protein kinase Cγ (PKCγ) to the cell membrane in many single, living rat basophilic leukemia cells grown on glass microscope slides. The enzyme showed two distinct modes of response. When calcium was released from internal stores, there was transient movement of PKCγ to the cell surface for only a few seconds. However, signals that caused entry of extracellular calcium caused a persistent translocation of the enzyme to the cell surface that lasted for more than half a minute. Cells showed primarily the former response to low doses of platelet activation factor, and the latter response to larger doses. The results help explain how a common messenger like calcium can control discrete cellular responses. M. N. Teruel, T. Meyer, Parallel single-cell monitoring of receptor-triggered membrane translocation of a calcium-sensing protein module. Science 295, 1910-1912 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"4 1","pages":"TW105 - tw105"},"PeriodicalIF":0.0,"publicationDate":"2002-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88747017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-02-26DOI: 10.1126/scisignal.1212002tw92
{"title":"Two Steps Forward . . .","authors":"","doi":"10.1126/scisignal.1212002tw92","DOIUrl":"https://doi.org/10.1126/scisignal.1212002tw92","url":null,"abstract":"Most conventional cancer drugs gradually lose their effectiveness because tumor cells are genetically unstable and can readily acquire mutations that confer drug resistance. It had been hoped that drug resistance would not be a problem for angiogenesis inhibitors because these drugs target endothelial cells in the tumor vasculature, which are genetically stable. However, Yu et al. found that mice bearing human colorectal tumors deficient in the tumor suppressor protein p53 were less responsive to antiangiogenic therapy than those bearing tumors with normal p53 function. The most likely explanation is that p53 loss confers an improved capacity to grow in low-oxygen conditions on the tumor cells. Because p53 is mutated in most human cancers, these results could have important implications for the design and interpretation of clinical trials testing antiangiogenic drugs. J. L. Yu, J. W. Rak, B. L. Coomber, D. J. Hicklin, R. S. Kerbel, Effect of p53 status on tumor response to antiangiogenic therapy. Science 295, 1526-1528 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"57 1","pages":"tw92 - tw92"},"PeriodicalIF":0.0,"publicationDate":"2002-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83334663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-02-19DOI: 10.1126/scisignal.1202002tw75
{"title":"Regulating Plant Steroids","authors":"","doi":"10.1126/scisignal.1202002tw75","DOIUrl":"https://doi.org/10.1126/scisignal.1202002tw75","url":null,"abstract":"Plant hormones include small peptides, complex chemicals, and steroids known as brassinosteroids. Brassinosteroids regulate, among other aspects, the plant's response to light conditions, its growth habit, and flowering patterns. The signaling pathways controlled by brassinosteroids are likely to be complex and highly branched. Li et al. have cloned and analyzed the BIN2 gene, which encodes a protein that resembles the SHAGGY-type kinases well known for controlling a variety of metabolic pathways in Drosophila, yeast, and mammalian cells. The BIN2 protein product function seemingly early in the brassinosteroid signaling response pathway, but just how closely linked its function is to the initial response of brassinosteroid and its receptor remains unclear. J. Li, K. H. Nam, Regulation of brassinosteroid signaling by a GSK3/SHAGGY-like kinase. Science 295, 1299-1301 (2002). [Abstract] [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"2 1","pages":"tw75 - tw75"},"PeriodicalIF":0.0,"publicationDate":"2002-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90045498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-02-19DOI: 10.1126/scisignal.1202002tw73
{"title":"Pull TAB1 to Activate","authors":"","doi":"10.1126/scisignal.1202002tw73","DOIUrl":"https://doi.org/10.1126/scisignal.1202002tw73","url":null,"abstract":"Members of the mitogen-activated protein kinase (MAPK) family control a wide range of cellular processes and are regulated as part of a cascade of protein kinases that are activated by sequential phosphorylation. Thus, MAPK kinases phosphorylate MAPKs on specific threonine and tyrosine residues, which leads to activation of the MAPK. Ge et al. (see the Perspective by Johnson) now show that there is another way to activate the so-called stress-activated MAPK known as p38α. They isolated proteins that interacted in a yeast system with human p38α and found TAB1 [transforming growth factor β-activated protein kinase 1 (TAK1)-binding protein 1], a protein previously implicated in activating a different protein kinase, TAK1. TAB1 directly interacted with p38α and thereby enhanced autophosphorylation and activation of the p38α enzyme. Studies of signaling to p38α in cultured cells indicated that some stimuli activate p38α by the conventional kinase cascade, whereas others require the interaction with TAB1 and activation of p38α autophosphorylation. B. Ge, H. Gram, F. Di Padova, B. Huang, L. New, R. J. Ulevitch, Y. Luo, J. Han, MAPKK-independent activation of p38α mediated by TAB1-dependent autophosphorylation of p38α. Science 295, 1291-1294 (2002). [Abstract] [Full Text] G. Johnson, Scaffolding proteins--more than meets the eye. Science 295, 1249-1250 (2002). [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"21 1","pages":"tw73 - tw73"},"PeriodicalIF":0.0,"publicationDate":"2002-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73343413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Science's STKEPub Date : 2002-02-12DOI: 10.1126/scisignal.1192002tw70
{"title":"Getting Into Shape","authors":"","doi":"10.1126/scisignal.1192002tw70","DOIUrl":"https://doi.org/10.1126/scisignal.1192002tw70","url":null,"abstract":"The cofactor complexes such as ARC (activator-recruited cofactor) and CRSP (cofactor required for Sp1) share several common subunits and mediate interactions between activators and the basal transcription apparatus. Taatjes et al. (see the Perspective by Meisterernst), using biochemical assays and electron microscopy, found that the larger complex, ARC, is composed of two multisubunit complexes, ARC-L and CRSP, and that transcriptional activity is only observed with CRSP. Structural determinations indicate that distinct conformations are induced in the CRSP complex by various activators. Therefore, different activators may allow for different transcriptional readouts based on the specific conformations that form. D. J. Taatjes, A. M. Näär, F. Andel III, E. Nogales, R. Tjian, Structure, function, and activator-induced conformations of the CRSP coactivator. Science 295, 1058-1062 (2002). [Abstract] [Full Text] M. Meisterernst, Mediator meets Morpheus. Science 295, 984-985 (2002). [Full Text]","PeriodicalId":21619,"journal":{"name":"Science's STKE","volume":"68 1","pages":"tw70 - tw70"},"PeriodicalIF":0.0,"publicationDate":"2002-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86813532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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