biosights: August 6, 2012 - Redistribution aids the pore

submitted by: JCB
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...

Asters help embryonic nuclei find their own space

submitted by: JCB
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...

T cell signaling goes with the flow

submitted by: JCB
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...

A new way forward for fibroblasts

submitted by: JCB
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...

PI3K's Pivotal Role in Cell Migration

submitted by: JCB
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...

Vinculin minds the endothelial gap

submitted by: JCB
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...

A Twin-Track Approach to Building Desmosomes

submitted by: JCB
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...