Rab15 effector protein: a novel protein for receptor recycling from the endocytic recycling compartment

Mol Biol Cell. 2005 Dec;16(12):5699-709. doi: 10.1091/mbc.e05-03-0204. Epub 2005 Sep 29.

Abstract

Sorting endosomes and the endocytic recycling compartment are critical intracellular stores for the rapid recycling of internalized membrane receptors to the cell surface in multiple cell types. However, the molecular mechanisms distinguishing fast receptor recycling from sorting endosomes and slow receptor recycling from the endocytic recycling compartment remain poorly understood. We previously reported that Rab15 differentially regulates transferrin receptor trafficking through sorting endosomes and the endocytic recycling compartment, suggesting a role for distinct Rab15-effector interactions at these endocytic compartments. In this study, we identified the novel protein Rab15 effector protein (REP15) as a binding partner for Rab15-GTP. REP15 is compartment specific, colocalizing with Rab15 and Rab11 on the endocytic recycling compartment but not with Rab15, Rab4, or early endosome antigen 1 on sorting endosomes. REP15 interacts directly with Rab15-GTP but not with Rab5 or Rab11. Consistent with its localization, REP15 overexpression and small interfering RNA-mediated depletion inhibited transferrin receptor recycling from the endocytic recycling compartment, without affecting receptor entry into or recycling from sorting endosomes. Our data identify REP15 as a compartment-specific protein for receptor recycling from the endocytic recycling compartment, highlighting that the rapid and slow modes of transferrin receptor recycling are mechanistically distinct pathways.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cells, Cultured
  • DNA, Complementary / metabolism
  • Endocytosis / physiology*
  • Guanosine Triphosphate / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Protein Transport
  • Receptors, Transferrin / metabolism*
  • Restriction Mapping
  • rab GTP-Binding Proteins / chemistry
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • DNA, Complementary
  • Membrane Proteins
  • Rab15 effector protein, human
  • Receptors, Transferrin
  • Guanosine Triphosphate
  • Rab15 protein, human
  • rab GTP-Binding Proteins