IN THIS ISSUE
CELL SCIENTISTS TO WATCH
CELL SCIENCE AT A GLANCE
Summary: In this Commentary, we review current evidence supporting intracellular PtdIns(4,5)P2 signaling, with a focus on PtdIns(4,5)P2 regulation of endolysosomal trafficking and protein recycling, as well as autophagic membrane trafficking.
Highlighted Article: During membrane stretching in yeast protoplasts, eisosomes disassemble to release membrane invaginations and to facilitate surface area expansion.
Regulation of polycystin-1 ciliary trafficking by motifs at its C-terminus and polycystin-2 but not by cleavage at the GPS site
Summary: Ciliary trafficking of polycystin-1 is regulated by multiple motifs at its C-terminus and by polycystin-2 but not by cleavage at its G-protein-coupled receptor proteolytic site.
Highlighted Article: The STIM1-interacting protein junctate generates Ca2+ hotspots that boost phagocytosis independently of STIM1 by promoting Ca2+ release from ER stores rather than by gating phagosomal Ca2+ channels.
Summary: The mechanism of ERK1c translocation to the Golgi in mitosis is elucidated, combining several independent Golgi-regulating processes into one coherent pathway.
Highlighted Article: LPS induces clustering of CD14 in the plasma membrane, which triggers PI(4,5)P2 generation in rafts that is required for maximal pro-inflammatory signaling of TLR4.
ERAD of proteins containing aberrant transmembrane domains requires ubiquitylation of cytoplasmic lysine residues
Summary: Proteins containing defective transmembrane domains are removed from the endoplasmic reticulum through a specific mechanism that depends upon the ubiquitylation of cytoplasmic lysine residues.
Highlighted Article: Membrane recruitment of the endosomal effector protein Rabaptin5 is shown to be mediated by both Rabex5 binding to ubiquitylated cargo and Rab4 to activate Rab5 in a feed-forward manner.
Plectin reinforces vascular integrity by mediating crosstalk between the vimentin and the actin networks
Summary: Plectin-arranged vimentin scaffolds keep actomyosin contractility ‘in-check’ and maintain cell–cell junction homeostasis, providing a new perspective on cytoskeleton-controlled vascular permeability.
Highlighted Article: The C-terminal Tyr residue of FUS can be phosphorylated by members of the Src kinase family. Phosphorylated Tyr526 impairs the interaction of FUS with transportin 1 and, potentially, its nuclear import.
A microtubule-independent role of p150glued in secretory cargo concentration at endoplasmic reticulum exit sites
Summary: p150glued stabilizes COPII pre-budding complexes on ER exit sites in a microtubule-independent manner, and it coordinates protein sorting, carrier formation and long-range transport events.
A new mitochondrial pool of cyclin E, regulated by Drp1, is linked to cell-density-dependent cell proliferation
Summary: Using mammalian cells and Drosophila, we have identified a new mitochondrial pool of the cell cycle regulator cyclin E that can be modulated by Drp1 to control cell proliferation.
Endocytic membrane turnover at the leading edge is driven by a transient interaction between Cdc42 and GRAF1
Summary: A transient interaction between Cdc42 and GRAF1 drives endocytic turnover at the leading edge, and controls the transition essential for endosomal maturation of plasma membrane internalised by this mechanism.
NRIP is newly identified as a Z-disc protein, activating calmodulin signaling for skeletal muscle contraction and regeneration
Summary: The interaction of NRIP with CaM results in the induction of slow myosin gene expression and mitochondrial activity, as well as the balancing of Ca2+ homeostasis; thus, loss of NRIP leads to muscle dystrophy.
α-Arrestins participate in cargo selection for both clathrin-independent and clathrin-mediated endocytosis
Summary: In yeast, α-arrestins bind the Rho1 GTPase and regulate internalization of selective cargo through the clathrin-independent endocytic pathway.
Activation of m1 muscarinic acetylcholine receptor induces surface transport of KCNQ channels through a CRMP-2-mediated pathway
Summary: Activation of m1 muscarinic acetylcholine receptor is well known to suppress KCNQ channel activities, but it also induces surface transport of KCNQ channels through a CRMP-2 mediated mechanism.