Hot off the presses! Dec 01 Nat Rev Mol Cell Biol

The Dec 01 issue of the Nat Rev Mol Cell Biol is now up on Pubget (About Nat Rev Mol Cell Biol): if you're at a subscribing institution, just click the link in the latest link at the home page. (Note you'll only be able to get all the PDFs in the issue if your institution subscribes to Pubget.)

Latest Articles Include:

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  - Nat Rev Mol Cell Biol 12(12):765 (2011)
  
• RNA: A new layer of regulation | PDF (245 KB)
  - Nat Rev Mol Cell Biol 12(12):766 (2011)
  Recently, Pandolfi and colleagues postulated that RNAs can communicate with each other by competing for binding to microRNAs (miRNAs), thereby regulating each other's expression. Four papers now provide support for this competing endogenous RNA (ceRNA) hypothesis and reveal roles for this type of regulation in development and cancer.
• Cell death: The single-membrane diet | PDF (194 KB)
  - Nat Rev Mol Cell Biol 12(12):767 (2011)
  Autophagy usually entails the recycling of cytoplasm and/or organelles that have been engulfed in double-membrane structures known as autophagosomes. Florey et al.
• Cell cycle: E2F1 ensures the endocycle | PDF (384 KB)
  - Nat Rev Mol Cell Biol 12(12):768 (2011)
  Edgar and colleagues have shown, using an elegant combination of genetic analysis and computational modelling, that endocycles in Drosophila melanogaster are driven by periodic oscillations in the transcription factor E2F1 and that E2F1 can sense changes in cell growth and adjust endocycles accordingly.
• Stem cells: Having the guts to grow | PDF (418 KB)
  - Nat Rev Mol Cell Biol 12(12):768 (2011)
  Stem cell activity functions to maintain tissue homeostasis in adult organs. Organs and tissues must also be capable of remodelling, growing or shrinking in response to environmental changes, but how these adaptive mechanisms are regulated is unknown.
• Cell signalling: mTOR targets its own inhibitor | PDF (213 KB)
  - Nat Rev Mol Cell Biol 12(12):769 (2011)
  Mammalian target of rapamycin complex 1 (mTORC1) and mTORC2 both contain, and are inhibited by, DEP domain-containing mTOR-interacting protein (DEPTOR). Upon serum stimulation, DEPTOR is degraded by the 26S proteasome to allow mTOR activation, but the ubiquitin E3 ligase driving this degradation was unknown.
• Plant cell biology: Sensing oxygen | PDF (271 KB)
  - Nat Rev Mol Cell Biol 12(12):770 (2011)
  To minimize damage caused by low levels of oxygen (hypoxia), cells rely on oxygen-sensing mechanisms, which drive downstream adaptive responses. Two studies now show that the N-end rule degradation pathway is part of the oxygen-sensing mechanism in Arabidopsis thaliana.
• Localizing cellular housekeeping | PDF (117 KB)
  - Nat Rev Mol Cell Biol 12(12):771 (2011)
  It is now well established that cellular 'housekeeping' activities, such as protein synthesis, take place at specific sites to control local signalling. Indeed, when I was working on my Ph.
• Development: Autophagy eliminates paternal mitochondria | PDF (247 KB)
  - Nat Rev Mol Cell Biol 12(12):771 (2011)
  Mitochondrial DNA (mtDNA) is thought to be maternally inherited, with paternal mtDNA being eliminated from fertilized oocytes by an unknown mechanism. Two groups now show that, in Caenorhabditis elegans, paternal mitochondria are degraded by fertilization-induced autophagy.
• Systems biology: Scaling in flies | PDF (85 KB)
  - Nat Rev Mol Cell Biol 12(12):767 (2011)
  How scaling, the process of expanding proportionally, occurs during development is not well understood. Using the Drosophila melanogaster wing as a model to study scaling quantitatively, Affolter and colleagues examined whether the activity gradient of the morphogen Decapentaplegic (DPP) scales during imaginal disc growth.
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  - Nat Rev Mol Cell Biol 12(12):767 (2011)
  
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  - Nat Rev Mol Cell Biol 12(12):767 (2011)
  
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  - Nat Rev Mol Cell Biol 12(12):770 (2011)
  
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  - Nat Rev Mol Cell Biol 12(12):770 (2011)
  
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  - Nat Rev Mol Cell Biol 12(12):770 (2011)
  
• Post-translational regulation of the microtubule cytoskeleton: mechanisms and functions
  - Nat Rev Mol Cell Biol 12(12):773 (2011)
  Half a century of biochemical and biophysical experiments has provided attractive models that may explain the diverse functions of microtubules within cells and organisms. However, the notion of functionally distinct microtubule types has not been explored with similar intensity, mostly because mechanisms for generating divergent microtubule species were not yet known. Cells generate distinct microtubule subtypes through expression of different tubulin isotypes and through post-translational modifications, such as detyrosination and further cleavage to Δ2-tubulin, acetylation, polyglutamylation and polyglycylation. The recent discovery of enzymes responsible for many tubulin post-translational modifications has enabled functional studies demonstrating that these post-translational modifications may regulate microtubule functions through an amazing range of mechanisms.
• Tail-anchored membrane protein insertion into the endoplasmic reticulum
  - Nat Rev Mol Cell Biol 12(12):787 (2011)
  Membrane proteins are inserted into the endoplasmic reticulum (ER) by two highly conserved parallel pathways. The well-studied co-translational pathway uses signal recognition particle (SRP) and its receptor for targeting and the SEC61 translocon for membrane integration. A recently discovered post-translational pathway uses an entirely different set of factors involving transmembrane domain (TMD)-selective cytosolic chaperones and an accompanying receptor at the ER. Elucidation of the structural and mechanistic basis of this post-translational membrane protein insertion pathway highlights general principles shared between the two pathways and key distinctions unique to each.
• Trithorax group proteins: switching genes on and keeping them active
  - Nat Rev Mol Cell Biol 12(12):799 (2011)
  Cellular memory is provided by two counteracting groups of chromatin proteins termed Trithorax group (TrxG) and Polycomb group (PcG) proteins. TrxG proteins activate transcription and are perhaps best known because of the involvement of the TrxG protein MLL in leukaemia. However, in terms of molecular analysis, they have lived in the shadow of their more famous counterparts, the PcG proteins. Recent advances have improved our understanding of TrxG protein function and demonstrated that the heterogeneous group of TrxG proteins is of critical importance in the epigenetic regulation of the cell cycle, senescence, DNA damage and stem cell biology.
• Gracefully ageing at 50, X-chromosome inactivation becomes a paradigm for RNA and chromatin control
  - Nat Rev Mol Cell Biol 12(12):815 (2011)
  The discovery of X-chromosome inactivation (XCI) celebrated its golden anniversary this year. Originally offered as an explanation for the establishment of genetic equality between males and females, 50 years on, XCI presents more than a curious gender-based phenomenon that causes silencing of sex chromosomes. How have the mysteries of XCI unfolded? And what general lessons can be extracted? Several of the cell biological mechanisms that are used to establish the inactive X chromosome, including regulatory networks of non-coding RNAs and unusual nuclear dynamics, are now suspected to hold true for processes occurring on a genome-wide scale.
• All tangled up: how cells direct, manage and exploit topoisomerase function
  - Nat Rev Mol Cell Biol 12(12):827 (2011)
  Topoisomerases are complex molecular machines that modulate DNA topology to maintain chromosome superstructure and integrity. Although capable of stand-alone activity in vitro, topoisomerases are frequently linked to larger pathways and systems that resolve specific DNA superstructures and intermediates arising from cellular processes such as DNA repair, transcription, replication and chromosome compaction. Topoisomerase activity is indispensible to cells, but requires the transient breakage of DNA strands. This property has been exploited, often for significant clinical benefit, by various exogenous agents that interfere with cell proliferation. Despite decades of study, surprising findings involving topoisomerases continue to emerge with respect to their cellular function, regulation and utility as therapeutic targets.