biosights: Decemeber 23, 2013 - Tumor cells WASH away the extracellular matrix

submitted by: JCB
Tumor cells invade through extracellular matrices by forming actin-rich structures called invadopodia, which contain the transmembrane matrix metalloproteinase MT1-MMP. Monteiro et al. reveal that the Arp2/3 activating protein WASH works with the exocyst complex to deliver MT1-MMP from late endosomes to the invadopodial plasma membrane. This biosights episode presents the paper by Monteiro et al. from the December 23, 2013, issue of The Journal of Cell Biology and includes an interview with...

biosights: November 25, 2013 - Caspases work as branch managers

submitted by: JCB
When a growing axon nears its target, it arborizes, or branches, to form numerous synaptic connections. Campbell and Okamoto reveal that localized caspase activation downstream of Slit-Robo signaling promotes arbor dynamics and restricts arbor growth. This biosights episode presents the paper by Campbell and Okamoto from the November 25, 2013, issue of The Journal of Cell Biology and includes an interview with lead author Douglas Campbell (formerly at the RIKEN Brain Science Institute,...

biosights: October 28, 2013 - A framework for understanding muscle microtubules

submitted by: JCB
The microtubules of skeletal muscle fibers are arranged into an orthogonal grid, but how this network is formed is unknown. Oddoux et al. reveal that the network is built by dynamic microtubules nucleated from Golgi elements. This biosights episode presents the paper by Oddoux et al. from the October 28, 2013, issue of The Journal of Cell Biology and includes an interview with senior author Evelyn Ralston (NIH, Bethesda, MD). Produced by Caitlin Sedwick and Ben Short. See the associated...

biosights: September 30, 2013 - The nodal network

submitted by: JCB
In addition to specialized actin structures such as lamellipodia and stress fibers, cells are thought to contain a contractile actomyosin matrix that maintains cell shape. Luo et al. describe the organization and dynamics of an actomyosin network that may fulfill this function. This network is formed by actin nodes that contain the formin DAAM1 and the crosslinker filamin A, and that are connected to each other by myosin II. This biosights episode presents the paper by Luo et al. from the...

biosights: September 2, 2013 - Shrinking microtubules pull the centrosome into place

submitted by: JCB
When a T cell encounters a target antigen-presenting cell, it moves its centrosome to the immunological synapse that connects the two cells. Yi et al. reveal that centrosome repositioning is a biphasic process driven by the dynein-dependent capture and depolymerization of microtubules. This biosights episode presents the paper by Yi et al. from the September 2, 2013, issue of The Journal of Cell Biology and includes an interview with senior author John Hammer (NHLBI, Bethesda, MD). Produced...

biosights: August 5, 2013 - Epithelia restored by healing waves

submitted by: JCB
Epithelial cells around the edge of a wound assemble an actomyosin cable that constricts to draw the wound closed, but the events that precede cable formation are largely unknown. Antunes et al. reveal that wounding induces a wave of actomyosin assembly and cell constriction that flows toward the wound edge to promote cable assembly and tissue repair. This biosights episode presents the paper by Antunes et al. from the July 22, 2013, issue of The Journal of Cell Biology and includes an...

biosights: July 8, 2013 - Vinculin delivers a clutch performance

submitted by: JCB
At the leading edge of migrating cells, actin assembly and membrane protrusion are closely coupled with the formation of integrin-based focal adhesions that attach to the extracellular matrix. Thievessen et al. reveal that the focal adhesion protein vinculin acts as part of a molecular clutch that engages actin flow to coordinate actin and focal adhesion dynamics. This biosights episode presents the paper by Thievessen et al. from the July 8, 2013, issue of The Journal of Cell Biology and...

biosights: June 10, 2013 - Netrin Throws Anchor Cells into the Breach

submitted by: JCB
Cell invasion through basement membranes is crucial for both normal development and cancer metastasis but relatively little is known about the process because it is difficult to observe in vivo. By imaging the invasion of anchor cells during C. elegans development, Hagedorn et al. reveal that, after invadopodia-like structures form an initial breach in the basement membrane, localized netrin signaling helps generate a stable invasive protrusion that widens the gap and directs the cell across...

biosights: May 13, 2013 - Ventral lamellipodia plug the gaps

submitted by: JCB
When leukocytes enter or exit the blood stream, they leave small wounds both in and between the vascular endothelial cells, which must be quickly repaired so that the endothelium can maintain its barrier function. Martinelli et al. reveal that wounding causes a loss of tension in endothelial cells, inducing the formation of ventral lamellipodia that close the holes left by transmigrating leukocytes. This biosights episode presents the paper by Martinelli et al. from the April 29, 2013, issue...

biosights: April 15, 2013 - Frog oocytes evade the checkpoint

submitted by: JCB
Most dividing cells possess a spindle assembly checkpoint that prevents them from entering anaphase until all their chromosomes are correctly attached to the metaphase spindle. Shao et al. reveal that Xenopus eggs lack this checkpoint, allowing them to undergo meiosis in the absence of microtubules or in the presence of monopolar spindles. This biosights episode presents the paper by Shao et al. from the April 15, 2013 issue of The Journal of Cell Biology and includes an interview with...