Proceedings of the Natural Academy of Sciences

Proceedings of the National Academy of Sciences RSS feed -- current issue
  • Imaging cycler microscopy [Biological Sciences]
    [Jan 2014]

    The article in PNAS by Gerdes et al. (1) adds to the evidence that spectral resolution limits of fluorescence microscopy can be overcome by reiterative cycles of tagging, imaging, and bleaching of fluorophores attached to ligands for target biomolecules. In fact, the robotic imaging cycler microscopes are based on this...
    Categories: Journal Articles
  • Highly multiplexed technologies [Biological Sciences]
    [Jan 2014]

    We are surprised by the concerns raised by Schubert et al. (1) regarding the quantitative nature and methodological approaches presented in our recent PNAS report (2). I will attempt to clarify some of confusion and misstatements, as several errors and misrepresentation of our data are stated in the critique. The...
    Categories: Journal Articles
  • Integrative pre-Columbian settlement model [Biological Sciences]
    [Jan 2014]

    Achilli et al. (1) present unique evidence concerning human mitogenomes and argue that such data are sufficient to generate a consensus scenario for the first settlement of the Americas. Here, we challenge their statement of having achieved a reconciling model because it ignores coherent ideas recently proposed by many researchers....
    Categories: Journal Articles
  • SQ-Dox nanoassemblies for anticancer therapy [Biochemistry]
    [Jan 2014]

    We identified that the chemical linkage of the anticancer drug doxorubicin onto squalene, a natural lipid precursor of the cholesterol’s biosynthesis, led to the formation of squalenoyl doxorubicin (SQ-Dox) nanoassemblies of 130-nm mean diameter, with an original “loop-train” structure. This unique nanomedicine demonstrates: (i) high drug payload, (ii) decreased toxicity...
    Categories: Journal Articles
  • Mechanics of myosin XXI [Biochemistry]
    [Jan 2014]

    Myosin XXI is the only myosin expressed in Leishmania parasites. Although it is assumed that it performs a variety of motile functions, the motor’s oligomerization states, cargo-binding, and motility are unknown. Here we show that binding of a single calmodulin causes the motor to adopt a monomeric state and to...
    Categories: Journal Articles
  • Apo-phytochromes modulate bacterial photosynthesis [Biochemistry]
    [Jan 2014]

    Bacteriophytochromes (BphPs) are light-sensing regulatory proteins encoded by photosynthetic and nonphotosynthetic bacteria. This protein class has been characterized structurally, but its biological activities remain relatively unexplored. Two BphPs in the anoxygenic photosynthetic bacterium Rhodopseudomonas palustris, designated regulatory proteins RpBphP2 and RpBphP3, are configured as light-regulated histidine kinases, which initiate a...
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  • TRIM14 builds mitochondrial antiviral signalosome [Microbiology]
    [Jan 2014]

    Innate immunity provides the first line of host defense against invading microbial pathogens. This defense involves retinoic acid-inducible gene-I–like receptors that detect viral RNA and activate the mitochondrial antiviral-signaling (MAVS) protein, an adaptor protein, leading to activation of the innate antiviral immune response. The mechanisms by which the MAVS signalosome...
    Categories: Journal Articles
  • ParP mediates polar sequestration of CheA [Microbiology]
    [Jan 2014]

    Bacterial chemotaxis proteins are organized into ordered arrays. In peritrichous organisms, such as Escherichia coli, stochastic assembly processes are thought to account for the placement of chemotaxis arrays, which are nonuniformly distributed. In contrast, we previously found that chemotactic signaling arrays in polarly flagellated vibrios are uniformly polar and that...
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  • MCV vFLIPs inhibit TBK1 activation [Microbiology]
    [Jan 2014]

    Apoptosis, NF-κB activation, and IRF3 activation are a triad of intrinsic immune responses that play crucial roles in the pathogenesis of infectious diseases, cancer, and autoimmunity. FLIPs are a family of viral and cellular proteins initially found to inhibit apoptosis and more recently to either up- or down-regulate NF-κB. As...
    Categories: Journal Articles
  • Gate in voltage-gated proton channels [Neuroscience]
    [Jan 2014]

    Voltage-gated proton (Hv1) channels play important roles in the respiratory burst, in pH regulation, in spermatozoa, in apoptosis, and in cancer metastasis. Unlike other voltage-gated cation channels, the Hv1 channel lacks a centrally located pore formed by the assembly of subunits. Instead, the proton permeation pathway in the Hv1 channel...
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  • Tissue specificity of MISS effects in vivo [Physiology]
    [Jan 2014]

    Estrogen receptor alpha (ERα) activation functions AF-1 and AF-2 classically mediate gene transcription in response to estradiol (E2). A fraction of ERα is targeted to plasma membrane and elicits membrane-initiated steroid signaling (MISS), but the physiological roles of MISS in vivo are poorly understood. We therefore generated a mouse with...
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  • Active visual sampling [Psychological and Cognitive Sciences]
    [Jan 2014]

    Human vision is an active process in which information is sampled during brief periods of stable fixation in between gaze shifts. Foveal analysis serves to identify the currently fixated object and has to be coordinated with a peripheral selection process of the next fixation location. Models of visual search and...
    Categories: Journal Articles
  • Integrated model of root vascular patterning [Plant Biology]
    [Jan 2014]

    As multicellular organisms grow, positional information is continually needed to regulate the pattern in which cells are arranged. In the Arabidopsis root, most cell types are organized in a radially symmetric pattern; however, a symmetry-breaking event generates bisymmetric auxin and cytokinin signaling domains in the stele. Bidirectional cross-talk between the...
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  • AtAtg8 cleavage specificity by AtAtg4 proteases [Plant Biology]
    [Jan 2014]

    Autophagy is a highly conserved biological process during which double membrane bound autophagosomes carry intracellular cargo material to the vacuole or lysosome for degradation and/or recycling. Autophagosome biogenesis requires Autophagy 4 (Atg4) cysteine protease-mediated processing of ubiquitin-like Atg8 proteins. Unlike single Atg4 and Atg8 genes in yeast, the Arabidopsis genome...
    Categories: Journal Articles
  • Biomarkers of sex differences in vaccine responses [Systems Biology]
    [Jan 2014]

    Females have generally more robust immune responses than males for reasons that are not well-understood. Here we used a systems analysis to investigate these differences by analyzing the neutralizing antibody response to a trivalent inactivated seasonal influenza vaccine (TIV) and a large number of immune system components, including serum cytokines...
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  • Correction for Tabot et al., Restoring the sense of touch with a prosthetic hand through a brain interface [Correction]
    [Jan 2014]

    NEUROSCIENCE Correction for “Restoring the sense of touch with a prosthetic hand through a brain interface,” by Gregg A. Tabot, John F. Dammann, Joshua A. Berg, Francesco V. Tenore, Jessica L. Boback, R. Jacob Vogelstein, and Sliman J. Bensmaia, which appeared in issue 45, November 5, 2013, of Proc Natl...
    Categories: Journal Articles
  • Correction for Labhsetwar et al., Heterogeneity in protein expression induces metabolic variability in a modeled Escherichia coli population [Correction]
    [Jan 2014]

    SYSTEMS BIOLOGY, CHEMISTRY Correction for “Heterogeneity in protein expression induces metabolic variability in a modeled Escherichia coli population,” by Piyush Labhsetwar, John Andrew Cole, Elijah Roberts, Nathan D. Price, and Zaida A. Luthey-Schulten, which appeared in issue 34, August 20, 2013, of Proc Natl Acad Sci USA (110:14006–14011; first published...
    Categories: Journal Articles
  • Correction for Hong et al., AMPA receptor exchange underlies transient memory destabilization on retrieval [Correction]
    [Jan 2014]

    NEUROSCIENCE Correction for “AMPA receptor exchange underlies transient memory destabilization on retrieval,” by Ingie Hong, Jeongyeon Kim, Jihye Kim, Sukwon Lee, Hyoung-Gon Ko, Karim Nader, Bong-Kiun Kaang, Richard W. Tsien, and Sukwoo Choi, which appeared in issue 20, May 14, 2013, of Proc Natl Acad Sci USA (110:8218–8223; first published...
    Categories: Journal Articles
  • Dynamic Notch interactions with superenhancers [Cell Biology]
    [Jan 2014]

    The main oncogenic driver in T-lymphoblastic leukemia is NOTCH1, which activates genes by forming chromatin-associated Notch transcription complexes. Gamma-secretase-inhibitor treatment prevents NOTCH1 nuclear localization, but most genes with NOTCH1-binding sites are insensitive to gamma-secretase inhibitors. Here, we demonstrate that fewer than 10% of NOTCH1-binding sites show dynamic changes in NOTCH1...
    Categories: Journal Articles
  • Exosomes enhance invasion of GIST [Cell Biology]
    [Jan 2014]

    During tumor development, constant interplay occurs between tumor cells and surrounding stromal cells. We report evidence that gastrointestinal stromal tumor (GIST) cells invade the interstitial stroma through the release of the oncogenic protein tyrosine kinase (KIT)-containing exosomes, which triggers the phenotypic conversion of progenitor smooth muscle cells to tumor-promoting cells....
    Categories: Journal Articles