Editors' Choice

Science  14 May 2021:
Vol. 372, Issue 6543, pp. 699
  1. Signal Transduction

    Imaging cancer cell by cell

    1. L. Bryan Ray

    Colored scanning electron micrograph of a colon cancer cell

    IMAGE: STEVE GSCHMEISSNER/SCIENCE SOURCE

    Experience in treating colorectal cancer shows that inhibition of the oncogene-activated mitogen-activated protein kinase (MAPK) signaling pathway is often more effective if the activity of the epidermal growth factor receptor, which acts upstream to activate the pathway, is also inhibited. To help clarify how such combined treatment might work, Ponsioen et al. used single-cell imaging of activity of the MAPK extracellular signal–regulated kinase (ERK) in patient-derived organoids. Oncogene-induced signaling showed that oscillations in ERK activity were amplified by epidermal growth factor signaling. The results help to explain how improved clinical practices in colorectal cancer treatment have been achieved.

    Nat. Cell Biol. 23, 377 (2021).

  2. DNA Repair

    Costs of moving stem cells

    1. Di Jiang

    Adult stem cells travel long distances to a wound to repair the damaged tissue. The potential cost of migration has been revealed in in vitro studies of cancer cell lines, dendritic cells, and primary stem cells. If these cells have to squeeze into wounds, then this constriction may cause DNA damage. Sahu et al. show that adult stem cells in Schmidtea mediterranea, a highly regenerative planarian flatworm, accumulate DNA damage as they migrate. The flatworm's stem cells actively repair the migration-inflicted DNA damage en route. The authors propose that during migration, the stem cells go through a “migration-damage-repair-migration” cycle as they home into a wound.

    eLife 10, e63779 (2021).

  3. Volcanology

    A pre-eruptive fever

    1. Brent Grocholski

    A steam-blast (phreatic) eruption from Mount Ontake, Japan

    PHOTO: AP PHOTO/KYODO NEWS

    Determining when volcanoes will erupt is important but difficult and often relies on measuring seismicity or deformation. Girona et al. added surface heat to that list, suggesting that a thermal signal precedes eruption by years. The increase in surface heat is subtle and likely due to underground hydrothermal activity, but it also can be detected with satellite observations and may allow early detection for the eruption of different types of volcanoes. This could be particularly important for phreatic eruptions that often occur with little to no warning.

    Nat. Geosci. 14, 238 (2021).

  4. Neurodevelopment

    Building bridges in the brain

    1. Pamela J. Hines

    Some 200 million axons connect the right hemisphere to the left through the brain's corpus callosum. A malformed or absent corpus callosum causes neurological or cognitive deficits. During development, astroglia build a substrate for axons to use in crossing the interhemispheric fissure. Signaling by Netrin 1 (NTN1) and its receptor, Deleted in Colorectal Carcinoma (DCC), guides axons to the midline. Morcom et al. show that NTN1 and DCC function even earlier to clear the path by regulating astroglial morphology and function. Without NTN1 and DCC function, astroglia that would normally build bridges across the interhemispheric fissure are unable to do so, and thus axons, no matter how well guided, struggle to build the corpus callosum.

    eLife 10, e61769 (2021)

  5. Enzyme Engineering

    Risk and replacement

    1. Michael A. Funk

    Much like the gears and chain of a well-used bicycle, a cell's metabolic enzymes age and collect damage and occasionally suffer catastrophic failure related to use. The rate of replacement required to maintain cellular function is determined by a combination of factors and differs for each enzyme. Hanson et al. analyzed protein turnover in bacteria, yeast, and plants and found associations among replacement rate, abundance, and metabolic flux. Up to 50% of metabolic enzymes may undergo self-inflicted, irreversible damage. Studying how to minimize these reactions without reducing activity could yield better catalysts for synthetic biology.

    Proc. Natl. Acad. Sci. U.S.A. 118, e2023348118 (2021).

  6. Autoimmune Diversity

    Population-level lupus

    1. Laura M. Zahn

    Autoimmune diseases often show polygenic inheritance, making the identification of potential causal genetic variants difficult, especially across ancestrally divergent populations. Andreoletti et al. examined the transcriptomes of bulk immune cells from 120 systematic lupus erythematosus (SLE) patients of Asian and European ancestry. Disease-specific genetic signatures were revealed, as well as ancestrally associated differences in SLE molecular pathways and the role of gene expression variation in disease severity. Because SLE severity differs among populations, this study highlights the need to examine disease genetics in multiethnic cohorts for underlying differences and to explore the clinical treatment options for individuals of differing ancestries.

    Commun. Biol. 4, 488 (2021).

  7. Magnetism

    A twist on the Ising model

    1. Jelena Stajic

    The material CoNb2O6 contains loosely bound zigzag chains of magnetic cobalt ions and is considered to be a model system for the so-called one-dimensional transverse field Ising model (TFIM). In this iconic model of quantum criticality, a string of particles with spin ½ orders with all of the spins pointing in the same direction, this ferromagnetic state melts at a critical value of an external transverse magnetic field. Morris et al. re-examined the applicability of this model to CoNb2O6 using time–domain terahertz spectroscopy and found that some of their results could not be explained by TFIM. Instead, the data fit what the authors dubbed a twisted Kitaev chain model, in which the Ising direction alternates along the chain.

    Nat. Phys. 10.1038/s41567-021-01208-0 (2021).

Stay Connected to Science