Catálogo de publicaciones - revistas

<jats:title>A cellular cholesterol sensor</jats:title> <jats:p> Cholesterol levels in cells are controlled by the sterol regulatory element–binding protein (SREBP) pathway. When the cell has sufficient cholesterol, the transcription factor that regulates cholesterol metabolism is sequestered at the endoplasmic reticulum membrane, but when cholesterol is depleted, the transcription factor is released to activate the expression of genes involved in cholesterol synthesis and uptake. Yan <jats:italic>et al.</jats:italic> determined the structure of a central complex in human SREBP containing the proteins Scap and Insig-2. These two membrane-embedded proteins undergo 25-hydroxycholesterol (25HC)–dependent association and must dissociate for the pathway to be activated. The structure shows that 25HC is sandwiched between Scap and Insig-2 to facilitate their association. A mutational analysis is consistent with the structural model. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abb2224">eabb2224</jats:related-article> </jats:p>

<jats:title>Turning a tumor suppressor into a target</jats:title> <jats:p> Tumor-suppressor genes such as <jats:italic>TP53</jats:italic> (tumor protein P53) play key roles in the pathogenesis of cancer but, unfortunately, they are difficult to target because they do not create an overactive protein that can be inhibited with a drug. Hsiue <jats:italic>et al.</jats:italic> discovered a way to target a cancer-associated mutant form of the p53 protein using the body's own immune system (see the Perspective by Weidanz). The authors identified a distinct fragment of this mutant protein, characterized the structural basis for its presentation to T cells, and designed a bispecific antibody to stimulate T cell killing of p53-mutant cancer cells. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abc8697">eabc8697</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6533" page="996" related-article-type="in-this-issue" vol="371" xlink:href="10.1126/science.abg5568">996</jats:related-article> </jats:p>

<jats:p> Our study showed that increases in seasonal productivity drive earlier autumn senescence of temperate trees. Norby argues that this finding is contradicted by observations from free-air CO <jats:sub>2</jats:sub> enrichment (FACE) experiments, where elevated CO <jats:sub>2</jats:sub> has been found to delay senescence in some cases. We provide a detailed answer showing that the results from FACE studies are in agreement with our conclusions. </jats:p>

<jats:p> Zani <jats:italic>et al</jats:italic> . (Research Articles, 27 November 2020, p. 1066) propose that enhancement of deciduous tree photosynthesis in a CO <jats:sub>2</jats:sub> -enriched atmosphere will advance autumn leaf senescence. This premise is not supported by consistent observations from free-air CO <jats:sub>2</jats:sub> enrichment (FACE) experiments. In most FACE experiments, leaf senescence or abscission was not altered or was delayed in trees exposed to elevated CO <jats:sub>2</jats:sub> . </jats:p>

<jats:p>The year 2020 saw a reusable rocket launch two astronauts into space, multiple COVID-19 vaccines developed in record time, and a robot that could write a persuasive op-ed. In the United States, the year also saw public distrust of science contribute to the worst health crisis in modern history. This contrast highlights a sharp dichotomy in the role of science in American public life: breathtaking discovery and innovation alongside growing distrust of scientific evidence and recommendations. How can the country reconcile this dissociation?</jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>Unique international trial has struggled to build on its first batch of results.</jats:p>

<jats:p> Critics question <jats:italic>NEJM</jats:italic> letter that downplayed the risks of keeping schools open with few precautions. </jats:p>

<jats:p>"Major innovation" emerged more than 3 billion years ago but was slow to catch on, study says.</jats:p>

<jats:p>Launch promises more deforestation data, but researchers fear government obstruction.</jats:p>