Related Experiment Video

Updated: Aug 25, 2026

Applications of pHluorin for Quantitative, Kinetic and High-throughput Analysis of Endocytosis in Budding Yeast
10:02

Applications of pHluorin for Quantitative, Kinetic and High-throughput Analysis of Endocytosis in Budding Yeast

Published on: October 23, 2016

Distinct caveolae-mediated endocytic pathways target the Golgi apparatus and the endoplasmic reticulum

Phuong U Le1, Ivan R Nabi

  • 1Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec, Canada.

Journal of Cell Science
|February 14, 2003
PubMed

Insights

Two distinct caveolae-mediated endocytic pathways exist, one directly to the ER for autocrine motility factor (AMF) and another to the Golgi for cholera toxin (CTX). Both pathways utilize cholesterol-rich membrane rafts.

Area of Science:

  • Cell biology
  • Molecular and cell biology
  • Endocytosis research

Background:

  • Autocrine motility factor (AMF) and cholera toxin (CTX) are internalized via endocytosis.
  • Caveolae and clathrin-coated vesicles are known endocytic mechanisms.
  • The specific pathways and destinations of AMF and CTX internalization require further elucidation.

Purpose of the Study:

  • To investigate the distinct endocytic pathways utilized by AMF and CTX.
  • To determine the role of caveolae, clathrin, and specific cellular compartments in the internalization of AMF and CTX.
  • To identify novel endocytic routes.

Main Methods:

  • Utilized methyl-beta-cyclodextrin to disrupt cholesterol-rich rafts.
  • Employed adenoviral expression of dynamin-1 K44A mutant and clathrin hub.
  • Investigated effects of brefeldin A, nocodazole, and temperature blocks on trafficking.
  • Assessed co-internalization and localization of AMF and CTX using specific inhibitors and markers.

Main Results:

  • AMF internalization into the endoplasmic reticulum (ER) is caveolae-mediated, raft-dependent, and cholesterol-sensitive.
  • CTX endocytosis is also caveolae-mediated, raft-dependent, and cholesterol-sensitive, with a distinct pathway to the Golgi apparatus.
  • Dynamin-1 K44A mutant and methyl-beta-cyclodextrin inhibited both pathways.
  • Caveolin-1 overexpression selectively diminished CTX endocytosis to the Golgi.
  • A novel, direct caveolae-mediated pathway for AMF from the plasma membrane to the ER was identified.

Conclusions:

  • Two distinct caveolae-mediated endocytic pathways exist: one directly to the ER for AMF and another to the Golgi for CTX.
  • Both pathways are sensitive to cholesterol depletion and dynamin, indicating involvement of lipid rafts.
  • The findings reveal a novel direct route for AMF internalization to the ER.

More Related Videos

Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass13:08

Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass

Published on: August 10, 2017

Analysis of Endocytic Uptake and Retrograde Transport to the Trans-Golgi Network Using Functionalized Nanobodies in Cultured Cells11:05

Analysis of Endocytic Uptake and Retrograde Transport to the Trans-Golgi Network Using Functionalized Nanobodies in Cultured Cells

Published on: February 21, 2019

Related Concept Videos

Golgi Apparatus01:49

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are transported by microtubule-based motor proteins and fuse together to form vesicular tubular clusters, subsequently arriving at the Golgi apparatus, a eukaryotic endomembrane organelle that often has a distinctive ribbon-like appearance.The Golgi apparatus is a major sorting and dispatch station for the products of the ER. Newly arriving vesicles enter...
COP Coated Vesicles00:59

COP Coated Vesicles

Membrane-enclosed structures called vesicles transport proteins and lipids across the cell. The vesicles derive their cargo from the plasma membrane, Golgi, ER, or endosome. Coated vesicles are spherical, protein-coated carriers with a 50–100 nm diameter that mediate bidirectional transport between the ER and the Golgi. The distribution of proteins between the ER and Golgi complex is dynamic and is maintained by different coated vesicles. Their formation is driven by the assembly of different...
Golgi Apparatus01:09

Golgi Apparatus

Properly folded and assembled proteins are selectively packaged into vesicles that exit the ER. Motor proteins transport these vesicles to the Golgi apparatus for adding modifications that make these proteins functional at their destination.
The Golgi apparatus is a eukaryotic organelle that has a distinctive ribbon-like appearance. It is a primary sorting and dispatch station for cargo arriving from the ER. Newly arriving vesicles enter the cis face of the Golgi, closest to the ER, and are...
Transport Across the Golgi01:26

Transport Across the Golgi

While it is unclear how molecules move between adjacent Golgi cisternae, it is apparent that the molecules move from cis- cisterna, the entry face, to the trans- cisterna, the exit face. Experiments initially suggested vesicles that bud from one cisterna and fuse with the next cisterna to transport proteins between the cisternae. This vesicular transport model describes the Golgi apparatus as a relatively static structure with a unique enzyme composition in each cisterna. Molecules are...
Clathrin Coated Vesicles01:12

Clathrin Coated Vesicles

Clathrin-coated vesicles use endocytosis to transport receptors and lysosomal hydrolases from the Golgi to the lysosome in the late secretory pathway. Clathrin-mediated endocytosis was the first described endocytic process, and Clathrin-coated vesicles remain one of the most well-studied transport vesicles. The molecular machinery that generates clathrin-coated vesicles comprises over 50 proteins that precisely coordinate vesicle formation. Cell surface receptors concentrated in indented sites...
Golgi Apparatus01:09

Golgi Apparatus

Properly folded and assembled proteins are selectively packaged into vesicles that exit the ER. Motor proteins transport these vesicles to the Golgi apparatus for adding modifications that make these proteins functional at their destination.
The Golgi apparatus is a eukaryotic organelle that has a distinctive ribbon-like appearance. It is a primary sorting and dispatch station for cargo arriving from the ER. Newly arriving vesicles enter the cis face of the Golgi, closest to the ER, and are...