Proceedings of the Natural Academy of Sciences

Proceedings of the National Academy of Sciences RSS feed -- current issue
  • Correction for Ehre et al., Overexpressing mouse model demonstrates the protective role of Muc5ac in the lungs [Correction]
    [Apr 2014]

    BIOCHEMISTRY Correction for “Overexpressing mouse model demonstrates the protective role of Muc5ac in the lungs,” by Camille Ehre, Erin N. Worthington, Rachael M. Liesman, Barbara R. Grubb, Diane Barbier, Wanda K. O’Neal, Jean-Michel Sallenave, Raymond J. Pickles, and Richard C. Boucher, which appeared in issue 41, October 9, 2012, of...
    Categories: Journal Articles
  • Correction for Tompkins et al., Testing Turing's theory of morphogenesis in chemical cells [Correction]
    [Apr 2014]

    PHYSICS Correction for “Testing Turing’s theory of morphogenesis in chemical cells,” by Nathan Tompkins, Ning Li, Camille Girabawe, Michael Heymann, G. Bard Ermentrout, Irving R. Epstein, and Seth Fraden, which appeared in issue 12, March 25, 2014, of Proc Natl Acad Sci USA (111:4397–4402; first published March 10, 2014; 10.1073/pnas.1322005111)....
    Categories: Journal Articles
  • Correction for Kusaba et al., Differentiated kidney epithelial cells repair injured proximal tubule [Correction]
    [Apr 2014]

    MEDICAL SCIENCES Correction for “Differentiated kidney epithelial cells repair injured proximal tubule,” by Tetsuro Kusaba, Matthew Lalli, Rafael Kramann, Akio Kobayashi, and Benjamin D. Humphreys, which appeared in issue 4, January 28, 2014, of Proc Natl Acad Sci USA (111:1527–1532; first published October 14, 2013; 10.1073/pnas.1310653110). The authors note that...
    Categories: Journal Articles
  • Biomimetic engineered skeletal muscle [Applied Biological Sciences]
    [Apr 2014]

    Tissue-engineered skeletal muscle can serve as a physiological model of natural muscle and a potential therapeutic vehicle for rapid repair of severe muscle loss and injury. Here, we describe a platform for engineering and testing highly functional biomimetic muscle tissues with a resident satellite cell niche and capacity for robust...
    Categories: Journal Articles
  • Docking protein mediated VEGF receptor signaling [Biochemistry]
    [Apr 2014]

    Vascular endothelial growth factors (VEGFs) signal via their cognate receptor tyrosine kinases designated VEGFR1-3. We report that the docking protein fibroblast growth factor receptor substrate 2 (FRS2α) plays a critical role in cell signaling via these receptors. In vitro FRS2α regulates VEGF-A and VEGF-C–dependent activation of extracellular signal-regulated receptor kinase...
    Categories: Journal Articles
  • Regulation of FGF23 by Fam20C phosphorylation [Biochemistry]
    [Apr 2014]

    The family with sequence similarity 20, member C (Fam20C) has recently been identified as the Golgi casein kinase. Fam20C phosphorylates secreted proteins on Ser-x-Glu/pSer motifs and loss-of-function mutations in the kinase cause Raine syndrome, an often-fatal osteosclerotic bone dysplasia. Fam20C is potentially an upstream regulator of the phosphate-regulating hormone fibroblast...
    Categories: Journal Articles
  • Chronology in lesion tolerance [Biochemistry]
    [Apr 2014]

    The encounter of a replication fork with a blocking DNA lesion is a common event that cells need to address properly to preserve genome integrity. Cells possess two main strategies to tolerate unrepaired lesions: potentially mutagenic translesion synthesis (TLS) and nonmutagenic damage avoidance (DA). Little is known about the partitioning...
    Categories: Journal Articles
  • smFRET study on programmed -1 frameshifting [Biophysics and Computational Biology]
    [Apr 2014]

    Ribosomal frameshifting occurs when a ribosome slips a few nucleotides on an mRNA and generates a new sequence of amino acids. Programmed −1 ribosomal frameshifting (−1PRF) is used in various systems to express two or more proteins from a single mRNA at precisely regulated levels. We used single-molecule fluorescence resonance...
    Categories: Journal Articles
  • Conformational landscape of the 26S proteasome [Biophysics and Computational Biology]
    [Apr 2014]

    The 26S proteasome is a 2.5 MDa molecular machine that executes the degradation of substrates of the ubiquitin–proteasome pathway. The molecular architecture of the 26S proteasome was recently established by cryo-EM approaches. For a detailed understanding of the sequence of events from the initial binding of polyubiquitylated substrates to the...
    Categories: Journal Articles
  • Crosstalk in two-component signaling [Biophysics and Computational Biology]
    [Apr 2014]

    Two-component signaling (TCS) serves as the dominant signaling modality in bacteria. A typical pathway includes a sensor histidine kinase (HK) that phosphorylates a response regulator (RR), modulating its activity in response to an incoming signal. Most HKs are bifunctional, acting as both kinase and phosphatase for their substrates. Unlike eukaryotic...
    Categories: Journal Articles
  • Electron transport via cytochrome c [Biophysics and Computational Biology]
    [Apr 2014]

    Electronic coupling to electrodes, Γ, as well as that across the examined molecules, H, is critical for solid-state electron transport (ETp) across proteins. Assessing the importance of each of these couplings helps to understand the mechanism of electron flow across molecules. We provide here experimental evidence for the importance of...
    Categories: Journal Articles
  • Dimeric kinesin-3 motors are superprocessive [Biophysics and Computational Biology]
    [Apr 2014]

    The kinesin-3 family is one of the largest among the kinesin superfamily and its members play important roles in a wide range of cellular transport activities, yet the molecular mechanisms of kinesin-3 regulation and cargo transport are largely unknown. We performed a comprehensive analysis of mammalian kinesin-3 motors from three...
    Categories: Journal Articles
  • Proline switch modulates force sensing of filamin [Biophysics and Computational Biology]
    [Apr 2014]

    Proline switches, controlled by cis–trans isomerization, have emerged as a particularly effective regulatory mechanism in a wide range of biological processes. In this study, we use single-molecule mechanical measurements to develop a full kinetic and energetic description of a highly conserved proline switch in the force-sensing domain 20 of human...
    Categories: Journal Articles
  • SUMO regulates cell differentiation [Cell Biology]
    [Apr 2014]

    The mammalian small ubiquitin-like modifiers (SUMOs) are actively involved in regulating differentiation of different cell types. However, the functional differences between SUMO isoforms and their mechanisms of action remain largely unknown. Using the ocular lens as a model system, we demonstrate that different SUMOs display distinct functions in regulating differentiation...
    Categories: Journal Articles
  • Combined hydrogels for pluripotent stem cells [Cell Biology]
    [Apr 2014]

    The ability of materials to define the architecture and microenvironment experienced by cells provides new opportunities to direct the fate of human pluripotent stem cells (HPSCs) [Robinton DA, Daley GQ (2012) Nature 481(7381):295–305]. However, the conditions required for self-renewal vs. differentiation of HPSCs are different, and a single system that...
    Categories: Journal Articles
  • Water drives the 20S proteasome gating reaction [Chemistry]
    [Apr 2014]

    The 20S core particle proteasome is a molecular machine playing an important role in cellular function by degrading protein substrates that no longer are required or that have become damaged. Regulation of proteasome activity occurs, in part, through a gating mechanism controlling the sizes of pores at the top and...
    Categories: Journal Articles
  • Spatial constraints control growth in tissues [Developmental Biology]
    [Apr 2014]

    Control of cell proliferation is a fundamental aspect of tissue formation in development and regeneration. Cells experience various spatial and mechanical constraints depending on their environmental context in the body, but we do not fully understand if and how such constraints influence cell cycle progression and thereby proliferation patterns in...
    Categories: Journal Articles
  • Temperature control of O-GlcNAc in poikilotherms [Developmental Biology]
    [Apr 2014]

    Effects of temperature on biological processes are complex. Diffusion is less affected than the diverse enzymatic reactions that have distinct individual temperature profiles. Hence thermal fluctuations pose a formidable challenge to ectothermic organisms in which body temperature is largely dictated by the ambient temperature. How cells in ectotherms cope with...
    Categories: Journal Articles
  • Methanethiol in hydrothermal fluids [Earth, Atmospheric, and Planetary Sciences]
    [Apr 2014]

    Simple alkyl thiols such as methanethiol (CH3SH) are widely speculated to form in seafloor hot spring fluids. Putative CH3SH synthesis by abiotic (nonbiological) reduction of inorganic carbon (CO2 or CO) has been invoked as an initiation reaction for the emergence of protometabolism and microbial life in primordial hydrothermal settings. Thiols...
    Categories: Journal Articles
  • Bipolar seesaw in Atlantic deep-water ventilation [Earth, Atmospheric, and Planetary Sciences]
    [Apr 2014]

    Recent theories for glacial–interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a “bipolar ventilation seesaw.” However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking. Here we present a record of North Atlantic...
    Categories: Journal Articles