Endocytosed transferrin receptors recycle via distinct dynamin and phosphatidylinositol 3-kinase-dependent pathways

J Biol Chem. 2002 Dec 13;277(50):48876-83. doi: 10.1074/jbc.M206271200. Epub 2002 Oct 7.

Abstract

Recycling of endocytosed membrane proteins involves passage through early endosomes and recycling endosomes. Previously, we demonstrated a role for clathrin-coated vesicles in transferrin receptor recycling. These clathrin-coated vesicles are formed from recycling endosomes in a process that was inhibited in dynamin-1(G273D)-overexpressing cells. Here we show a second transferrin recycling pathway, which requires phosphatidylinositol 3-kinase activity. Two unrelated phosphatidylinositol 3-kinase inhibitors, LY294002 and wortmannin, retained endocytosed transferrin in early endosomes but did not affect transfer through recycling endosomes. The inhibitory effects of LY294002 and dynamin-1(G273D) on transferrin recycling were additive. In combination with brefeldin A, a drug that prevents the formation of clathrin-coated buds at recycling endosomes, LY294002 inhibited transferrin recycling synergistically. Collectively, these data indicate two distinct recycling pathways. One pathway involves transfer from early endosomes to recycling endosomes, from where clathrin/dynamin-coated vesicles provide for further transport, whereas the other route bypasses recycling endosomes and requires phosphatidylinositol 3-kinase activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromones / pharmacology
  • Dynamin I / metabolism*
  • Endocytosis*
  • Endosomes / ultrastructure
  • Enzyme Inhibitors / pharmacology
  • HeLa Cells
  • Humans
  • Immunohistochemistry
  • Morpholines / pharmacology
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphoinositide-3 Kinase Inhibitors
  • Receptors, Transferrin / metabolism*

Substances

  • Chromones
  • Enzyme Inhibitors
  • Morpholines
  • Phosphoinositide-3 Kinase Inhibitors
  • Receptors, Transferrin
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • Dynamin I