Galectin-3 drives glycosphingolipid-dependent biogenesis of clathrin-independent carriers

Nat Cell Biol. 2014 Jun;16(6):595-606. doi: 10.1038/ncb2970. Epub 2014 May 18.

Abstract

Several cell surface molecules including signalling receptors are internalized by clathrin-independent endocytosis. How this process is initiated, how cargo proteins are sorted and membranes are bent remains unknown. Here, we found that a carbohydrate-binding protein, galectin-3 (Gal3), triggered the glycosphingolipid (GSL)-dependent biogenesis of a morphologically distinct class of endocytic structures, termed clathrin-independent carriers (CLICs). Super-resolution and reconstitution studies showed that Gal3 required GSLs for clustering and membrane bending. Gal3 interacted with a defined set of cargo proteins. Cellular uptake of the CLIC cargo CD44 was dependent on Gal3, GSLs and branched N-glycosylation. Endocytosis of β1-integrin was also reliant on Gal3. Analysis of different galectins revealed a distinct profile of cargoes and uptake structures, suggesting the existence of different CLIC populations. We conclude that Gal3 functionally integrates carbohydrate specificity on cargo proteins with the capacity of GSLs to drive clathrin-independent plasma membrane bending as a first step of CLIC biogenesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Video-Audio Media

MeSH terms

  • Animals
  • Blood Proteins
  • Endocytosis*
  • Galectin 3 / genetics
  • Galectin 3 / metabolism*
  • Galectins
  • Glycosphingolipids / metabolism*
  • Glycosylation
  • HeLa Cells
  • Humans
  • Hyaluronan Receptors / metabolism
  • Integrin beta1 / metabolism
  • Mice
  • Protein Processing, Post-Translational
  • Protein Transport
  • RNA Interference
  • Transfection
  • Transport Vesicles / metabolism*

Substances

  • Blood Proteins
  • CD44 protein, human
  • Cd44 protein, mouse
  • Galectin 3
  • Galectins
  • Glycosphingolipids
  • Hyaluronan Receptors
  • Integrin beta1
  • LGALS3 protein, human