Collapsin response mediator protein-2 (Crmp2) regulates trafficking by linking endocytic regulatory proteins to dynein motors

J Biol Chem. 2010 Oct 15;285(42):31918-22. doi: 10.1074/jbc.C110.166066. Epub 2010 Aug 27.

Abstract

Endocytosis is a conserved cellular process in which nutrients, lipids, and receptors are internalized and transported to early endosomes, where they are sorted and either channeled to degradative pathways or recycled to the plasma membrane. MICAL-L1 and EHD1 are important regulatory proteins that control key endocytic transport steps. However, the precise mechanisms by which they mediate transport, and particularly the mode by which they connect to motor proteins, have remained enigmatic. Here we have identified the collapsin response mediator protein-2 (Crmp2) as an interaction partner of MICAL-L1 in non-neuronal cells. Crmp2 interacts with tubulin dimers and kinesin and negatively regulates dynein-based transport in neuronal cells, but its expression and function in non-neuronal cells have remained poorly characterized. Upon Crmp2 depletion, we observed dramatic relocalization of internalized transferrin (Tf) from peripheral vesicles to the endocytic recycling compartment (ERC), similar to the effect of depleting either MICAL-L1 or EHD1. Moreover, Tf relocalization to the ERC could be inhibited by interfering with microtubule polymerization, consistent with a role for uncoupled motor protein-based transport upon depletion of Crmp2, MICAL-L1, or EHD1. Finally, transfection of dynamitin, a component of the dynactin complex whose overexpression inhibits dynein activity, prevented the relocalization of internalized Tf to the ERC upon depletion of Crmp2, MICAL-L1, or EHD1. These data provide the first trafficking regulatory role for Crmp2 in non-neuronal cells and support a model in which Crmp2 is an important endocytic regulatory protein that links MICAL-L1·EHD1-based vesicular transport to dynein motors.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Cattle
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism*
  • Dyneins / metabolism*
  • Endocytosis / physiology*
  • HeLa Cells
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • LIM Domain Proteins
  • Microfilament Proteins
  • Mixed Function Oxygenases
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Protein Binding
  • RNA, Small Interfering / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • rab GTP-Binding Proteins / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Cytoskeletal Proteins
  • EHD1 protein, human
  • Intercellular Signaling Peptides and Proteins
  • Intracellular Signaling Peptides and Proteins
  • LIM Domain Proteins
  • Microfilament Proteins
  • Nerve Tissue Proteins
  • RNA, Small Interfering
  • Recombinant Fusion Proteins
  • Vesicular Transport Proteins
  • collapsin response mediator protein-2
  • MICAL1 protein, human
  • Mixed Function Oxygenases
  • Dyneins
  • rab GTP-Binding Proteins