Issues
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Cover Image
Cover Image
ON THE COVER
Confocal projection of a fixed Drosophila embryo expressing endogenously YFP-tagged Rab7 as marker for late endosomes (yellow), and stained for actin (phalloidin-ATTO647, white), the tracheal lumen (Chitin-binding protein-Alexa546, magenta), and nuclei (DAPI, blue). Late endosomes organize actin at the growing tip of tracheal terminal cells to regulate their morphogenesis. Image © Ríos-Barrera and Leptin, 2022 https://doi.org/10.1083/jcb.202106124 - PDF Icon PDF LinkTable of Contents
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People & Ideas
Bo Zhong: Captive by the viral immune escape
Bo Zhong studies the regulation of the antiviral innate immunity, inflammation, and tumorigenesis by the protein ubiquitination system.
Spotlights
A back-up source of microtubules for the midbody during cytokinesis
Gilles R.X. Hickson previews work from the Canman laboratory that finds that during cytokinesis, astral microtubules can serve as the source for assembling the midbody in cases when central spindle microtubules are absent.
Plectin pulls it together, coupling the cortical actin and intermediate filament cytoskeletons
Broussard and Green highlight work from Prechova et al. that identifies plectin as a mechanical integrator of cytoskeletal and adhesive networks for cellular tensional homeostasis.
Reviews
Neuronal endolysosomal transport and lysosomal functionality in maintaining axonostasis
Roney et al. review recent advances in how axonal endolysosomal trafficking, distribution, and functionality maintain distal degradation capacity in neuronal health and become disrupted in several neurodegenerative diseases.
Reports
Functional midbody assembly in the absence of a central spindle
Hirsch et al. found that genetic disruption of central spindle microtubule assembly in C. elegans embryos does not block cytokinesis or midbody assembly. These central spindle–independent midbodies appeared to form from astral microtubules, bundled by contractile ring constriction.
Vps13-like proteins provide phosphatidylethanolamine for GPI anchor synthesis in the ER
Glycosylphosphatidylinositol (GPI) anchors attach many proteins to the extracellular surface of the plasma membrane. Anchor synthesis occurs in the ER and requires phosphatidylethanolamine (PE). Toulmay et al. show that tubelike lipid transport proteins bring PE to the ER to support GPI anchor production.
Neuralized-like protein 4 (NEURL4) mediates ADP-ribosylation of mitochondrial proteins
Cardamone et al. characterize NEURL4 as a novel mitochondrial ART enzyme required for the maintenance of mtDNA integrity and the regulation of mitochondrial homeostasis through ADP-ribosylation.
Articles
A loop extrusion–independent mechanism contributes to condensin I–mediated chromosome shaping
Kinoshita et al. address the role of condensin I in chromosome assembly and identify two classes of mutations that cause hyper- and hypocompaction phenotypes in Xenopus egg extracts. The study reveals that a loop extrusion–independent mechanism also contributes to chromosome assembly and shaping.
Active RB causes visible changes in nuclear organization
Krishnan et al. use FISH to show that specific forms of RB induce changes in the organization of euchromatin and heterochromatin domains. These changes are visible under the microscope, occur after cell cycle arrest, are separable from senescence, and represent an E2F-independent activity of RB.
Karyopherin enrichment and compensation fortifies the nuclear pore complex against nucleocytoplasmic leakage
Kalita et al. show that cargo leakage out of the nucleus is prevented by an enrichment of different soluble receptors, termed “karyopherins,” that are able to compensate for one another to reinforce the nuclear pore complex barrier in vivo.
Regulating peroxisome–ER contacts via the ACBD5-VAPB tether by FFAT motif phosphorylation and GSK3β
Kors et al. reveal that peroxisome–ER associations via the ACBD5-VAPB tether are regulated by phosphorylation and GSK3β in mammalian cells. Phosphorylation sites in the FFAT-like motif of ACBD5 affect the binding to VAPB—and thus peroxisome–ER contact sites—differently.
Differential metabolism of arsenicals regulates Fps1-mediated arsenite transport
Lee and Levin investigate the question of how different stressors can drive divergent outputs from an active SAPK. The work describes the mechanism by which two forms of arsenic that both activate the yeast SAPK Hog1 differentially regulate the glycerol channel Fps1.
An endosome-associated actin network involved in directed apical plasma membrane growth
Drosophila tracheal terminal cells form subcellular tubes by invaginating their apical plasma membrane. Ríos-Barrera and Leptin show that late endosomes guide subcellular tube elongation toward the direction of cell growth by promoting F-actin organization between the tip of the subcellular tube and the advancing tip of the cell.
The core autophagy protein ATG9A controls dynamics of cell protrusions and directed migration
Campisi et al. uncover a new function of the core autophagy protein ATG9A in cell migration by demonstrating that ATG9A-positive vesicles are mobilized during chemotactic stimulation to participate in the extension and stabilization of leading-edge protrusions.
Plectin-mediated cytoskeletal crosstalk controls cell tension and cohesion in epithelial sheets
Prechova et al. demonstrate that cytolinker protein plectin is essential for the formation of the circumferential keratin rim, organization of radial keratin spokes, and desmosomal patterning. Thus, plectin controls cell cohesion and maintenance of epithelial stability.
Tools
Detection and quantification of the vacuolar H+ATPase using the Legionella effector protein SidK
SidK is introduced as a highly specific probe to visualize and quantify the proton-pumping vacuolar H+ATPases (V-ATPases) of mammalian cells and yeast.