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...

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...

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...

Phosphoinositide 3-kinase (PI3K) and its phospholipid products are polarized toward the front of migrating fibroblasts, but their exact function in persistent motility remains unclear. Welf et al. reveal that PI3K signaling helps reorient migrating fibroblasts by stabilizing branched protrusions at the leading edge, allowing the cell to pivot and move in a different direction. This biosights episode presents the paper by Welf et al. from the April 2, 2012, issue of The Journal of Cell...

The adhesions between endothelial cells transiently remodel in response to angiogenic growth factors and inflammatory cytokines. Huveneers et al. reveal that remodeling takes place at a subset of adhesions called focal adherens junctions, which recruit the mechanosensory protein Vinculin to resist tension from the actomyosin cytoskeleton and avoid excessive disruption during the remodeling process. This biosights episode presents the paper by Huveneers et al. from the March 5, 2012, issue of...

Autophagy is a cellular degradation pathway essential for neuronal survival, but little is known about the dynamics of autophagic organelles in neurons. Maday et al. reveal that autophagosomes form and engulf cargo at the distal tips of neurites and then mature into degradative autolysosomes as they move toward the cell body. This biosights episode presents the paper by Maday et al. from the February 20, 2012, issue of The Journal of Cell Biology and includes an interview with authors Sandra...

Desmosomes are intercellular adhesions whose adhesive core is formed by two distinct classes of cadherin molecules -- desmogleins and desmocollins. Nekrasova et al. reveal that these two cadherins are independently transported to the cell surface by two different kinesin motors. This biosights episode presents the paper by Nekrasova et al. from the December 26, 2011, issue of The Journal of Cell Biology and includes an interview with senior author Kathleen Green (Northwestern University...

The endoplasmic reticulum is a complex network of interconnected membrane tubules and cisternae. West et al. use electron tomography to reveal the full diversity of ER structures present in budding yeast and how these structures pass from the mother cell into the bud. This biosights episode presents the paper by West et al. from the April 18, 2011, issue of The Journal of Cell Biology, and includes an interview with senior author Gia Voeltz (University of Colorado, Boulder). Produced by...