biosights

How cell shape changes unfold

Under certain conditions, cells form protrusions that oscillate rapidly around the cell periphery. Kapustina et al. reveal that these oscillatory protrusions, which may be related to processes involved in amoeboid cell migration, are driven by the cyclic folding and unfolding of the plasma membrane and its underlying actin cortex. This biosights episode presents the paper by Kapustina et al. from the January 7, 2013, issue of The Journal of Cell Biology and includes an interview with lead author Maryna Kapustina (University of North Carolina, Chapel Hill). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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At the end of cytokinesis, the microtubule-rich midbody connecting the daughter cells is either shed into the extracellular space or retained by one of the daughters. Chai et al. find that the midbodies released from C. elegans Q neuroblasts are cleared via a pathway that closely mimics the removal of apoptotic cell corpses. This biosights episode presents the paper by Chai et al. from the December 24, 2012 issue of the Journal of Cell Biology and includes an interview with senior author Guangshuo Ou (Institute of Biophysics, Chinese Academy of Sciences, Beijing, China). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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Fission yeast are thought to assemble their cytokinetic actomyosin rings from actin filaments nucleated at myosin-containing nodes around the cell equator. Using an improved actin-binding probe, Huang et al. find that actin cables are nucleated all over the cortex of mitotic fission yeast and are transported to the division site for incorporation into the contractile ring. This biosights episode presents the paper by Huang et al. from the November 26, 2012, issue of The Journal of Cell Biology and includes an interview with senior author Mohan Balasubramanian (Temasek Life Sciences Laboratory, Singapore). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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The mechanical properties of the extracellular matrix are known to regulate the migration of single cells, but whether substrate stiffness also affects collective cell migration is unclear. Ng et al. reveal that epithelial sheets move faster on stiffer matrices due to increased myosin contractility and mechanical coupling through cell-cell adhesions. This biosights episode presents the paper by Ng et al. from the October 29, 2012, issue of The Journal of Cell Biology and includes an interview with authors Rosa Ng, Gaudenz Danuser, and Joan Brugge (Harvard Medical School, Boston, MA). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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The position of the mitotic spindle is controlled by the microtubule-based motor dynein and a ternary complex of the proteins NuMA, LGN, and Ga. Kotak et al. demonstrate that the ternary complex's primary function is to localize dynein to the cell cortex and that cortical dynein is sufficient to position the mitotic spindle in HeLa cells. This biosights episode presents the paper by Kotak et al. from the October 1, 2012, issue of The Journal of Cell Biology and includes an interview with author Pierre Gonczy (EPFL, Lausanne, Switzerland). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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C. elegans embryos are protected by a trilaminar eggshell that is thought to make the embryos impermeable to small molecules. Olson et al. describe the hierarchical assembly of the different eggshell layers but reveal that the permeability barrier is a distinct structure that lies in between the shell and the embryo surface. This biosights episode presents the paper by Olson et al. from the August 20, 2012, issue of The Journal of Cell Biology and includes an interview with authors Sara Olson (Pomona College, Claremont, CA) and Karen Oegema (Ludwig Institute for Cancer Research, UC San Diego, CA). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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In animal cells, the nuclear lamina keeps nuclear pore complexes evenly distributed throughout the nuclear envelope. Steinberg et al. reveal that fungi, which lack nuclear laminae, prevent their nuclear pores from clustering by moving them around on cytoskeletal tracks, a process that also helps to organize fungal chromosomes and optimize nucleocytoplasmic transport. This biosights episode presents the paper by Steinberg et al. from the August 6, 2012, issue of the Journal of Cell Biology and includes an interview with senior author Gero Steinberg (University of Exeter, UK). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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In early Drosophila embryos, nuclei undergo rapid, synchronous divisions without being separated into individual cells by cytokinesis. Telley et al. develop a cell-free assay to reveal that microtubule asters help disperse the nuclei throughout the embryonic cytoplasm, moving them to the right position for development to continue. This biosights episode presents the paper by Telley et al. from the June 25, 2012, issue of The Journal of Cell Biology and includes an interview with lead author Ivo Telley (EMBL, Heidelberg, Germany). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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Activated T cell receptors stimulate actin polymerization at the periphery of the immunological synapses that form between lymphocytes and antigen-presenting cells. Babich et al. reveal that the retrograde flow of actin, largely driven by continuous polymerization, is required to sustain downstream signaling events and T cell activation. This biosights episode presents the paper by Babich et al. from the June 11, 2012 issue of The Journal of Cell Biology and includes an interview with senior author Janis Burkhardt (University of Pennsylvania, Philadelphia). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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Fibroblasts moving across two-dimensional surfaces form lamellipodial protrusions at their leading edge, but how cells move through three-dimensional environments is less well understood. Petrie et al. reveal that, depending on the strength of intracellular RhoA signaling and on the elastic properties of the extracellular matrix, fibroblasts can migrate through 3D environments using either lamellipodia or blunt, cylindrical protrusions called lobopodia. This biosights episode presents the paper by Petrie et al. from the April 30, 2012, issue of The Journal of Cell Biology and includes an interview with first author Ryan Petrie (NIH, Bethesda, MD). Produced by Caitlin Sedwick and Ben Short. See the associated paper in JCB for details on the funding provided to support this original research.

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The Rockefeller University Press [email protected]