Table of contents


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Editorial

Italy fails to nurture knowledge p1373

doi:10.1038/ncb1208-1373

Silvio Berlusconi's government seems set on its course to reform Italy's troubled education system through heavy cuts in funding to schools, universities and scientific research, prompting a belated flurry of protests.


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Obituary

George Palade 1912–2008 p1374

David D. Sabatini

doi:10.1038/ncb1208-1374


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Meeting Report

Exploring the pole: an EMBO conference on centrosomes and spindle pole bodies pp1375 - 1378

Sue L. Jaspersen & Tim Stearns

doi:10.1038/ncb1208-1375


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Commentary

Do the protocadherins Fat and Dachsous link up to determine both planar cell polarity and the dimensions of organs? pp1379 - 1382

Peter A. Lawrence, Gary Struhl & José Casal

doi:10.1038/ncb1208-1379


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News and Views

A TRP channel-steroid marriage pp1383 - 1384

Bernd Nilius & Thomas Voets

doi:10.1038/ncb1208-1383

A surprising functional association between TRPM3, a mysterious member of the family of transient receptor potential (TRP) cation channels, and the sulphated version of pregnenolone, 'mother' of all steroid hormones, has been identified.


Under arrest in mitosis: Cdc20 dies twice pp1385 - 1387

Andrew M. Fry & Hiroyuki Yamano

doi:10.1038/ncb1208-1385

The spindle assembly checkpoint is crucial for maintaining genome integrity in dividing cells by preventing premature chromosome segregation. Degradation of the APC/C activator Cdc20 seems to be an essential and conserved mechanism to maintain this checkpoint in the presence of chromosomes that are not attached to the mitotic spindle.


Staying alive: apoptosome feedback inhibition pp1387 - 1388

Hermann Steller

doi:10.1038/ncb1208-1387

Studies in Drosophila melanogaster reveal a mechanism for regulating caspases, the key executioners of the apoptotic cell-death program. An initiator caspase and its activating partner promote degradation of each other, thereby limiting the levels of the active protease complex. This negative-feedback inhibition helps to explain how cells avoid unwanted caspase activation and apoptosis.


Out of the jaws of death: PRMT5 steers p53 pp1389 - 1390

Shelley L. Berger

doi:10.1038/ncb1208-1389

The tumour suppressor p53 triggers either cell-cycle arrest or apoptosis. Now, arginine methylation joins a panoply of other post-translational modifications that regulate p53. PRMT5 mediates p53 methylation, which disposes the cell to arrest rather than death.


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Research Highlights

Research highlights p1391

Nathalie Le Bot, Bernd Pulverer, Christina Karlsson Rosenthal & Sowmya Swaminathan

doi:10.1038/ncb1208-1391


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Articles

Fluctuations of intracellular forces during cell protrusion pp1393 - 1400

Lin Ji, James Lim & Gaudenz Danuser

doi:10.1038/ncb1797

Modelling intracellular force variations at cell protrusions suggests that cell adhesion is regulated at the interface between vinculin and integrin and reveals a putative feedback between increases in tension and F-actin assembly.


Nature and anisotropy of cortical forces orienting Drosophila tissue morphogenesis pp1401 - 1410

Matteo Rauzi, Pascale Verant, Thomas Lecuit & Pierre-François Lenne

doi:10.1038/ncb1798

Quantitative analysis and mathematical modelling show that cortical tension anisotropy at apical cell junctions drives cell neighbour exchanges that are responsible for elongation of Drosophila embryos. This anisotropy depends on myosin II activity.


The APC/C maintains the spindle assembly checkpoint by targeting Cdc20 for destruction pp1411 - 1420

Jakob Nilsson, Mona Yekezare, Jeremy Minshull & Jonathon Pines

doi:10.1038/ncb1799

Ubiquitin-dependent degradation of Cdc20 by the APC/C ligase is a conserved mechanism essential for maintaining the spindle assembly checkpoint activated by unattached chromosomes.

See also: News and Views by Fry & Yamano


Transient receptor potential M3 channels are ionotropic steroid receptors in pancreatic beta cells pp1421 - 1430

Thomas F.J. Wagner, Sabine Loch, Sachar Lambert, Isabelle Straub, Stefanie Mannebach, Ilka Mathar, Martina Düfer, Annette Lis, Veit Flockerzi, Stephan E. Philipp & Johannes Oberwinkler

doi:10.1038/ncb1801

In an unanticipated cross-talk between the steroid and insulin endocrine systems, the neuroactive steroid pregnenolone sulphate is found to activate the TRPM3 channel, leading to enhanced insulin secretion from pancreatic islets.

See also: News and Views by Nilius & Voets


Arginine methylation regulates the p53 response pp1431 - 1439

Martin Jansson, Stephen T. Durant, Er-Chieh Cho, Sharon Sheahan, Mariola Edelmann, Benedikt Kessler & Nicholas B. La Thangue

doi:10.1038/ncb1802

The tumour suppressor p53 is subject to complex regulation and arginine methylation is now shown to provide an additional level of control. The protein arginine methyltransferase (PRMT) 5 is recruited by Strap to methylate p53 in response to DNA damage, governing the p53 response.

See also: News and Views by Berger


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Letters

Regulation of the Drosophila apoptosome through feedback inhibition pp1440 - 1446

Peter J. Shapiro, Hans H. Hsu, Heekyung Jung, Edith S. Robbins & Hyung Don Ryoo

doi:10.1038/ncb1803

The apoptotic inhibitor IAP1 regulates a feedback loop between the caspase Dronc1 and its apoptosome adaptor Apaf1 to maintain low caspase activity in cells that are not destined to die.

See also: News and Views by Steller


X-linked and cellular IAPs modulate the stability of C-RAF kinase and cell motility pp1447 - 1455

Taner Dogan, Gregory S. Harms, Mirko Hekman, Christiaan Karreman, Tripat Kaur Oberoi, Emad S. Alnemri, Ulf R. Rapp & Krishnaraj Rajalingam

doi:10.1038/ncb1804

The anti-apoptotic regulators XIAP and c-IAPs promote turnover of the cRAF kinase to control cell migration. XIAP binding facilitates ubiquitylation of cRAF through the ubiquitin ligase CHIP.


An H+ P-ATPase on the tonoplast determines vacuolar pH and flower colour pp1456 - 1462

Walter Verweij, Cornelis Spelt, Gian-Pietro Di Sansebastiano, Joop Vermeer, Lara Reale, Francesco Ferranti, Ronald Koes & Francesca Quattrocchio

doi:10.1038/ncb1805

P-ATPases in plants are typically thought to act at the plasma membrane. In contrast, PH5, a P-type H+ ATPase functions within the vacuolar membrane to control acidification during flower coloration.


Activation of TGF-beta/activin signalling resets the circadian clock through rapid induction of Dec1 transcripts pp1463 - 1469

Naohiro Kon, Tsuyoshi Hirota, Takeshi Kawamoto, Yukio Kato, Tadashi Tsubota & Yoshitaka Fukada

doi:10.1038/ncb1806

The circadian clock is synchronized with the environment. In mammals, besides light input mediated by Per genes, little is known about resetting mechanisms. TGF-beta and activin reset the clock by acting on the circadian gene Dec1.


Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers pp1470 - 1476

Johan Skog, Tom Würdinger, Sjoerd van Rijn, Dimphna H. Meijer, Laura Gainche, William T. Curry, Jr., Bob S. Carter, Anna M. Krichevsky & Xandra O. Breakefield

doi:10.1038/ncb1800

Human glioblastoma cells release microvesicles containing a diverse set of proteins, miRNAs and mRNAs, which can be taken up by normal host cells that translate the mRNA. Glioma-derived microvesicles carrying the specific tumour markers EGFRvIII and miRNA-21 promote cell proliferation and may serve as a diagnostic tool.


Glucose metabolism inhibits apoptosis in neurons and cancer cells by redox inactivation of cytochrome c pp1477 - 1483

Allyson E. Vaughn & Mohanish Deshmukh

doi:10.1038/ncb1807

Neurons and cancer cells metabolize glucose extensively. Intracellular gluthatione produced by this metabolic pathway reduces cytochrome c release from mitochondria to increase cell survival.


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Erratum

A model for transmission of the H3K27me3 epigenetic mark p1484

Klaus H. Hansen, Adrian P. Bracken, Diego Pasini, Nikolaj Dietrich, Simmi S. Gehani, Astrid Monrad, Juri Rappsilber, Mads Lerdrup & Kristian Helin

doi:10.1038/ncb1208-1484


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