Issues
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Cover Image
Cover Image
ON THE COVER
The image is a single frame from a light sheet movie of an immature frog oocyte exhibiting induced cortical waves of Rho activity (cyan) and actin filaments (orange). The waves are manifestations of a cortical pattern-forming circuit based on Rho, actin filaments, the Rho GEF Ect2 and the Rho GAP RGA-3/4. This conserved, versatile circuit controls cortical behaviors ranging from pulsed contraction to cytokinesis. Image © Michaud et al., 2022 https://doi.org/10.1083/jcb.202203017 - PDF Icon PDF LinkTable of Contents
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People & Ideas
Sara Cuylen-Haering: Cellular soaps to keep neat chromosomes
Sara Cuylen-Haering studies the molecular mechanisms driving phase separation of chromosomes and other cellular organelles, with a special focus on biological surfactants.
Spotlights
Plan your trip before you leave: The neutrophils’ search-and-run journey
Stopp and Sixt preview work from the Sarris lab showing that neutophrils follow a two-step search-and-run strategy to approach alarm gradients within complex tissue environments in living organisms.
Reports
Regulation of the COPII secretory machinery via focal adhesions and extracellular matrix signaling
Jung et al. use a high-throughput siRNA-based screen to explore synergistic interactions between the cytoskeleton and the secretory machinery. They found a novel role of focal adhesions and extracellular matrix signaling in the regulation of COPII subunit SEC23A, with implications for ER-to-Golgi transport.
α-Catenin links integrin adhesions to F-actin to regulate ECM mechanosensing and rigidity dependence
Mukherjee et al. show that α-catenin undergoes retrograde flow with F-actin from the cell edge, leading to its association with vinculin in integrin adhesions. This interaction regulates extracellular matrix mechanosensing, and in its absence, mesenchymal cells gain the ability to grow on soft matrices.
PEAK1 Y635 phosphorylation regulates cell migration through association with Tensin3 and integrins
Zuidema et al. demonstrate that Tyr-635 phosphorylation of PEAK1 regulates cell migration through association with Tensin3 and localization of PEAK1 in focal adhesions.
Coro1B and Coro1C regulate lamellipodia dynamics and cell motility by tuning branched actin turnover
A new conditional knockout cell line for coronins clarifies important functional details about its role in regulating ADF/cofilin function.
Articles
Mechanistic basis for Sgo1-mediated centromere localization and function of the CPC
Abad and Gupta et al. reveal the molecular basis for the interaction between the CPC and Sgo1, two essential regulators of chromosome segregation. Their work provides a rationale for the kinetochore–proximal centromere recruitment of the CPC and highlights its requirement for high-fidelity chromosome segregation.
A versatile cortical pattern-forming circuit based on Rho, F-actin, Ect2, and RGA-3/4
Michaud et al. identify Ect2 and RGA-3/4 as core components of the cortical excitability circuit associated with cytokinesis. Additionally, they demonstrate that the immature Xenopus oocyte is a powerful model for characterizing excitable dynamics.
Coronin 1C restricts endosomal branched actin to organize ER contact and endosome fission
ER contact sites define the position of endosome bud fission during actin-dependent cargo sorting. Striepen Voeltz show that COR1C confines actin at endosome bud necks. Depleting COR1C and its paralogs causes ARP2/3-dependent actin extension along the bud, resulting in loss of ER contact, and blocks endosome fission.
Cvm1 is a component of multiple vacuolar contact sites required for sphingolipid homeostasis
Membrane contact sites allow organelles to communicate with each other. Bisinski et al. show that Cvm1 is a novel component of three different contacts involving the yeast lysosome-like vacuole. These contacts both control and are regulated by the levels of sphingolipids in the cell.
JIP3 interacts with dynein and kinesin-1 to regulate bidirectional organelle transport
Celestino, Gama, Castro-Rodrigues et al. characterize how the retrograde motor dynein interacts with cargo adaptors of the RILP/JIP3 superfamily and selectively uncouple dynein and the opposing motor kinesin-1 from JIP3/UNC-16 in Caenorhabditis elegans, which reveals that JIP3 drives bidirectional organelle transport in neurons.
IRSp53 promotes postsynaptic density formation and actin filament bundling
IRSp53 is abundantly expressed at the postsynaptic densities of neuronal synapses, but its action mechanism has been poorly understood. Feng et al. demonstrate that IRSp53 is a key scaffold linker for the PSD core and pallium via promoting phase separation of the PSD assembly, and they also uncover a direct role of IRSp53 in actin modulation essential for dendritic spine development.
A two-step search and run response to gradients shapes leukocyte navigation in vivo
Previous studies of chemotaxis have focused on protrusions and in vitro models. Georgantzoglou et al. show that protrusive structures in neutrophils only drive a first exploratory stage in vivo, while a second stage of actin flows and contractility is required for the ultimate motion response.
Tools
Dissecting protein tyrosine phosphatase signaling by engineered chemogenetic control of its activity
Fauser et al. engineer a chemogenetic allosteric switch that allows for the regulation of the activity of protein tyrosine phosphatases, as well as for their activation within specific protein complexes. Using this tool, they dissect parallel signaling pathways and identify dynamic processes regulated by different Shp2-mediated signaling complexes.