Before we get to the research papers published in today’s new issue of JCB, I’ll quickly point you in the direction of this editorial by our new Editor-In-Chief, Alan Hall, which discusses how JCB, and cell biology in general, can support scientific progress in the years ahead. A must-read!
As Dr. Hall says, “the goal of JCB is ‘simply’ to publish the very best work in cell biology.” And today’s new issue certainly delivers! Lu et al. describe how budding yeast ensure that proteins are degraded in the correct order during mitosis. Using single cell analyses, the researchers find that the ubiquitin ligase APC/CCdc20 targets the S phase cyclin Clb5 for degradation 6 minutes earlier than it targets the chromatid cohesion regulator securin. As detailed in this week’s In Focus, this six-minute difference is maintained by multiple mechanisms that either promote or inhibit the substrate proteins’ direct or indirect association with the APC/C complex.
Burke et al. describe how the coiled-coil protein Chibby promotes the formation of a membranous cap that helps centrioles dock with the plasma membrane during ciliogenesis. Chibby binds to the distal appendages of centrioles in multiciliated tracheal cells, and promotes formation of the so-called ciliary vesicle. As described here, centrioles fail to assemble a ciliary vesicle in the absence of Chibby, and therefore show reduced docking to the apical membrane of differentiating tracheal cells.
Schwarz and Blower reveal that a calcium-regulated ribonuclease promotes ER network assembly. The enzyme, called EndoU, cleaves RNAs on the surface of ER membranes, promoting the release of RNA and ribosomal proteins into the cytosol and stimulating the fusion of ER membranes into dense tubular networks in both HeLa cells and Xenopus egg extracts. More here.
Elsewhere, Liu and Novick demonstrate that the polarity protein Bem1p recruits the exocyst subunit Exo70p to the site of polarized exocytosis in budding yeast (summary here), while Shin et al. describe how dynamin-mediated endocytosis promotes cell-cell fusion during osteoclast and myoblast differentiation, and Dadgar et al. reveal that asynchronous tissue regeneration causes fibrosis in Duchenne Muscular Dystrophy patients. You can learn more about these last two studies in this month’s biobytes podcast, which you can listen to below or subscribe to in iTunes.
That’s all for now, but there are plenty of other good papers to discover by visiting our table of contents page here.
Cover image showing centrioles in a multiciliated tracheal epithelial cell © 2014 Burke et al.