Scripps VIVO scripps research logo

  • Index
  • Log in
  • Home
  • People
  • Organizations
  • Research
  • Events
Search form
As of April 1st VIVO Scientific Profiles will no longer updated for faculty, and the link to VIVO will be removed from the library website. Faculty profile pages will continue to be updated via Interfolio. VIVO will continue being used behind the scenes to update graduate student profiles. Please contact helplib@scripps.edu if you have questions.
How to download citations from VIVO | Alternative profile options

Role for phosphatidylinositol 3-kinase in the sorting and transport of newly synthesized lysosomal-enzymes in mammalian-cells

Academic Article
uri icon
  • Overview
  • Identity
  • Additional Document Info
  • View All
scroll to property group menus

Overview

authors

  • Brown, W. J.
  • Dewald, D. B.
  • Emr, S. D.
  • Plutner, H.
  • Balch, William E.

publication date

  • August 1995

journal

  • Journal of Cell Biology  Journal

abstract

  • Previous work with the yeast Saccharomyces cerevisiae has demonstrated a role for a phosphatidylinositol-specific PI 3-kinase, the product of the VPS34 gene, in the targeting of newly synthesized proteins to the vacuole, an organelle functionally equivalent to mammalian lysosomes (Schu, P. V., K. Takegawa, M. J. Fry, J. H. Stack, M. D. Waterfield, and S. D. Emr. 1993. Science [Wash. DC]. 260:88-91). The activity of Vps34p kinase is significantly reduced by the PI 3-kinase inhibitors wortmannin, a fungal metabolite, and LY294002, a quercetin analog (Stack, J. H., and S. D. Emr. 1994. J. Biol. Chem. 269:31552-31562). We show here that at concentrations which inhibit VPS34-encoded PI 3-kinase activity, wortmannin also inhibits the processing and delivery of newly synthesized cathepsin D to lysosomes in mammalian cells with half-maximal inhibition of delivery occurring at 100 nM wortmannin. As a result of wortmannin action, newly synthesized, unprocessed cathepsin D is secreted into the media. Moreover, after accumulation in the trans-Golgi network (TGN) at 20 degrees C, cathepsin D was rapidly missorted to the secretory pathway after addition of wortmannin and shifting to 37 degrees C. At concentrations that inhibited lysosomal enzyme delivery, both wortmannin and LY294002 caused a highly specific dilation of mannose 6-phosphate receptor (M6PR)-enriched vesicles of the prelysosome compartment (PLC), which swelled to approximately 1 micron within 15 min after treatment. With increasing time, the inhibitors caused a significant yet reversible change in M6PR distribution. By 3 h of treatment, the swollen PLC vacuoles were essentially depleted of receptors and, in addition, there was a fourfold loss of receptors from the cell surface. However, M6PRs were still abundant in the TGN. These results are most consistent with the interpretation that PI 3-kinase regulates the trafficking of lysosomal enzymes by interfering with a M6PR-dependent sorting event in the TGN. Moreover, they provide evidence that trafficking of soluble hydrolases to mammalian lysosomes and yeast vacuoles rely on similar regulatory mechanisms.

subject areas

  • Acridine Orange
  • Androstadienes
  • Animals
  • Biological Transport
  • Cathepsin D
  • Cell Compartmentation
  • Cells, Cultured
  • Chromones
  • Enzyme Inhibitors
  • Fluorescent Antibody Technique
  • Golgi Apparatus
  • Hydrolases
  • Lysosomes
  • Models, Biological
  • Morpholines
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor)
  • Protein Processing, Post-Translational
  • Receptor, IGF Type 2
  • Vacuoles
scroll to property group menus

Identity

International Standard Serial Number (ISSN)

  • 0021-9525

Digital Object Identifier (DOI)

  • 10.1083/jcb.130.4.781

PubMed ID

  • 7642697
scroll to property group menus

Additional Document Info

start page

  • 781

end page

  • 796

volume

  • 130

issue

  • 4

©2022 The Scripps Research Institute | Terms of Use | Powered by VIVO

  • About
  • Contact Us
  • Support