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.
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.
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.
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.
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.
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.
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.