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This month in Bio-Med Roundup: · Lamason et al. identified a zebrafish pigmentation gene, the human counterpart of which may play a role in determining skin color. · Finger et al. discovered that ATP is the neurotransmitter that relays information from the taste buds to the gustatory nerves. · Boehm and Slack found that a developmental timing microRNA and its target regulate life span in the nematode C. elegans. · Shaw et al. showed that the kinase LKB1 plays a critical role in liver metabolism and glucose homeostasis. Jump to:
A Role for the Phagosome in Cytokine Secretion ( R. Z. Murray, J. G. Kay, D. G. Sangermani, J. L. Stow The specialized segment of immune cell membrane that engulfs microbes and then destroys them is also dedicated to secreting factors that cause local inflammation. http://www.sciencemag.org/cgi/content/abstract/310/5753/1492 Chromosome Alignment and Segregation Regulated by Ubiquitination of Survivin ( Q. P. Vong, K. Cao, H. Y. Li, P. A. Iglesias, Y. Zheng Ubiquitin, a peptide tag that usually marks proteins for degradation, unexpectedly also controls the cellular location of a key cell cycle protein during mitosis. http://www.sciencemag.org/cgi/content/abstract/310/5753/1499 See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5753/1443 A Systems Model of Signaling Identifies a Molecular Basis Set for Cytokine-Induced Apoptosis ( K. A. Janes, J. G. Albeck, S. Gaudet, P. K. Sorger, D. A. Lauffenburger, M. B. Yaffe A model of the interactions among cellular signaling components predicts previously unknown regulatory pathways for cell death. http://www.sciencemag.org/cgi/content/abstract/310/5754/1646 A Conserved Checkpoint Monitors Meiotic Chromosome Synapsis in Caenorhabditis elegans ( N. Bhalla and A. F. Dernburg In nematodes, a newly recognized checkpoint prevents meiosis unless the homologous chromosomes are paired, and a second checkpoint validates proper recombination. http://www.sciencemag.org/cgi/content/abstract/310/5754/1683 Protein Synthesis upon Acute Nutrient Restriction Relies on Proteasome Function ( R. M. Vabulas and F. Ulrich Hartl When mammalian cells are starved of amino acids, a cellular organelle, the proteasome, degrades preexisting proteins to supply the amino acids needed for protein synthesis. http://www.sciencemag.org/cgi/content/abstract/310/5756/1960 Stem Cell Self-Renewal Controlled by Chromatin Remodeling Factors ( R. Xi and T. Xie Hormonal signals that maintain stem cells in a pluripotent state in the Drosophila ovary act by regulating proteins that control how much transcription occurs from chromatin. http://www.sciencemag.org/cgi/content/abstract/310/5753/1487 fgf20 Is Essential for Initiating Zebrafish Fin Regeneration ( G. G. Whitehead, S. Makino, C.-L. Lien, M. T. Keating A newly described growth factor controls the earliest stages of limb regeneration in zebrafish, but does not otherwise participate in development. http://www.sciencemag.org/cgi/content/abstract/310/5756/1957 Restoration of Auditory Nerve Synapses in Cats by Cochlear Implants ( D. K. Ryugo, E. A. Kretzmer, J. K. Niparko In congenitally deaf cats, electrical stimulation of the cochlea for 6 months restored the abnormal synapse structure in the auditory nerve and their ability to hear. http://www.sciencemag.org/cgi/content/abstract/310/5753/1490 ATP Signaling Is Crucial for Communication from Taste Buds to Gustatory Nerves ( T. E. Finger, V. Danilova, J. Barrows, D. L. Bartel, A. J. Vigers, L. Stone, G. Hellekant, S. C. Kinnamon The long-sought neurotransmitter that communicates taste information from tongue receptors to the gustatory nerve is ATP, also used in other sensory systems. http://www.sciencemag.org/cgi/content/abstract/310/5753/1495 Equivalent Effects of Snake PLA2 Neurotoxins and Lysophospholipid–Fatty Acid Mixtures ( M. Rigoni, P. Caccin, S. Gschmeissner, G. Koster , A. D. Postle, O. Rossetto, G. Schiavo, C. Montecucco The paralytic effects of a snake venom on neuromuscular synapses are mimicked by a mixture of fatty acids and lipids, suggesting its mechanism of action. http://www.sciencemag.org/cgi/content/abstract/310/5754/1678 See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5754/1626 Neural Systems Responding to Degrees of Uncertainty in Human Decision-Making ( M. Hsu, M. Bhatt, R. Adolphs, D. Tranel, C. F. Camerer People prefer choices with defined risk to those with ambiguous risk, but damage to the emotion-processing areas of the brain eliminates this preference. http://www.sciencemag.org/cgi/content/abstract/310/5754/1680 See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5754/1624 Long-Term Modulation of Electrical Synapses in the Mammalian Thalamus ( C. E. Landisman and B. W. Connors In inhibitory neurons of the rat thalamus, current flow through gap junctions—conduction pores between neurons—is modulated by electrical activity and neurotransmitters. http://www.sciencemag.org/cgi/content/abstract/310/5755/1809 Glial Membranes at the Node of Ranvier Prevent Neurite Outgrowth ( J. K. Huang, G. R. Phillips, A. D. Roth, L. Pedraza, W. Shan, W. Belkaid, S. Mi, A. Fex-Svenningsen, L. Florens, J. R. Yates III, D. R. Colman Sections of neuronal axons that are devoid of myelin trapping are prevented from sprouting inappropriately by adjacent glial membranes containing an inhibitory protein. http://www.sciencemag.org/cgi/content/abstract/310/5755/1813 Category-Specific Cortical Activity Precedes Retrieval During Memory Search ( S. M. Polyn, V. S. Natu, J. D. Cohen, K. A. Norman Brain activation patterns characteristic of a previously observed object can be seen seconds before subjects consciously remember that object. http://www.sciencemag.org/cgi/content/abstract/310/5756/1963 Prostaglandin E2 Promotes M. D. Castellone, H. Teramoto, B. O. Williams, K. M. Druey, J. S. Gutkind A factor that causes inflammation enhances colon-cancer growth through a newly described signaling pathway. http://www.sciencemag.org/cgi/content/abstract/310/5753/1504 Increase in Activity During Calorie Restriction Requires Sirt1 ( D. Chen, A. D. Steele, S. Lindquist, L. Guarente Mice usually increase their physical activity when fed a calorie-deficient diet, but not when they have a mutation in an aging-related protein. http://www.sciencemag.org/cgi/content/abstract/310/5754/1641 The Kinase LKB1 Mediates Glucose Homeostasis in Liver and Therapeutic Effects of Metformin ( R. J. Shaw, K. A. Lamia, D. Vasquez, S.-H. Koo, N. Bardeesy, R. A. DePinho, M. Montminy, L. C. Cantley A key phosphorylating enzyme in the liver, which is required for the action of a diabetes drug, regulates glucose synthesis and blood levels. http://www.sciencemag.org/cgi/content/abstract/310/5754/1642 Inducible Nitric Oxide Synthase Binds, S-Nitrosylates, and Activates Cyclooxygenase-2 ( S. F. Kim, D. A. Huri, S. H. Snyder Two important enzymes that induce inflammation in mammals physically interact and augment each other’s activity, providing a potential target for anti-inflammatory drugs. http://www.sciencemag.org/cgi/content/abstract/310/5756/1966 Evidence for Macromolecular Protein Rings in the Absence of Bulk Water ( B. T. Ruotolo, K. Giles, I. Campuzano, A. M. Sandercock, R. H. Bateman, C. V. Robinson Protein-protein assemblies and protein-ligand complexes retain their overall structures during mass spectrometry, suggesting a new tool for structural determinations. http://www.sciencemag.org/cgi/content/abstract/310/5754/1658 Snapshot of Activated G Proteins at the Membrane: The Gáq-GRK2-Gâã Complex ( V. M. Tesmer, T. Kawano, A. Shankaranarayanan, T. Kozasa, J. J. G. Tesmer After hormonal stimulation, one of three subunits of a membrane-bound signaling protein dissociates and interacts with a target protein to activate it. http://www.sciencemag.org/cgi/content/abstract/310/5754/1686 Ubiquitin-Binding Domains in Y-Family Polymerases Regulate Translesion Synthesis ( M. Bienko, C. M. Green, N. Crosetto, F. Rudolf, G. Zapart, B. Coull, P. Kannouche, G. Wider, M. Peter, A. R. Lehmann, K. Hofmann, I. Dikic The small peptide ubiquitin, known to mark proteins for degradation, also triggers the activity of a group of polymerases specialized for repairing DNA damage. http://www.sciencemag.org/cgi/content/abstract/310/5755/1821 X-ray Structure of the EmrE Multidrug Transporter in Complex with a Substrate ( O. Pornillos, Y.-J. Chen, A. P. Chen, G. Chang A membrane protein that transports drugs out of bacteria is an antiparallel dimer, with asymmetry between the two subunits driving unidirectional transport. Divergent Immunoglobulin G Subclass Activity Through Selective Fc Receptor Binding ( F. Nimmerjahn and J. V. Ravetch The ability of certain natural and manufactured antibodies to elicit different immune defenses can be predicted by their relative affinities for activating or inhibitory receptors. http://www.sciencemag.org/cgi/content/abstract/310/5753/1510 See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5753/1442 Diversity and Function of Adaptive Immune Receptors in a Jawless Vertebrate ( M. N. Adler, I. B. Rogozin, L. M. Iyer, G. V. Glazko, M. D. Cooper, Z. Pancer Lampreys insert different sequence modules into a constant gene to generate antigen-specific lymphocyte receptors, which can protect them against infection. http://www.sciencemag.org/cgi/content/abstract/310/5756/1970 Structural Roles for Human Translation Factor eIF3 in Initiation of Protein Synthesis ( B. Siridechadilok, C. S. Fraser, R. J. Hall, J. A. Doudna, A protein complex that binds to the ends of mRNAs to position them on the ribosome unexpectedly binds in the same way to internal ribosome entry sites within mRNAs. http://www.sciencemag.org/cgi/content/abstract/310/5753/1513 The Widespread Impact of Mammalian MicroRNAs on mRNA Repression and Evolution ( K. K.-H. Farh, A. Grimson, C. Jan, B. P. Lewis, W. K. Johnston, L. P. Lim, C. B. Burge, D. P. Bartel In mammals, recently discovered small regulatory microRNAs influence the expression or evolution of most genes. http://www.sciencemag.org/cgi/content/abstract/310/5755/1817 A Developmental Timing MicroRNA and Its Target Regulate Life Span in C. elegans ( M. Boehm and F. Slack In the nematode, a known RNA regulator that synchronizes development also controls life span through an insulin signaling pathway, suggesting a biological clock for aging. http://www.sciencemag.org/cgi/content/abstract/310/5756/1954 See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5756/1911 SLC24A5, a Putative Cation Exchanger, Affects Pigmentation in Zebrafish and Humans ( R. L. Lamason, M.-A. P. K. Mohideen, J. R. Mest, A. C. Wong, H. L. Norton, M. C. Aros, M. J. Jurynec, X. Mao, V. R. Humphreville, J. E.Humbert et al. Identification of a gene that controls pigmentation in zebrafish points to a similar gene that may play a key role in human skin color. http://www.sciencemag.org/cgi/content/abstract/310/5755/1782 Chitin Induces Natural Competence in Vibrio cholerae ( K. L.Meibom, M. Blokesch, N. A. Dolganov, C.-Y.Wu, G. K. Schoolnik When grown under natural conditions, cholera bacteria can release and exchange functional DNA, an ability not seen in 60 years of study in the laboratory. http://www.sciencemag.org/cgi/content/abstract/310/5755/1824 See related Perspective at http://www.sciencemag.org/cgi/content/summary/310/5755/1775
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