MAP7D2 Localizes to the Proximal Axon and Locally Promotes Kinesin-1-Mediated Cargo Transport into the Axon

Cell Rep. 2019 Feb 19;26(8):1988-1999.e6. doi: 10.1016/j.celrep.2019.01.084.

Abstract

The motor protein kinesin-1 plays an important role in polarized sorting of transport vesicles to the axon. However, the mechanism by which the axonal entry of kinesin-1-dependent cargo transport is regulated remains unclear. Microtubule-associated protein MAP7 (ensconsin in Drosophila) is an essential kinesin-1 cofactor and promotes kinesin-1 recruitment to microtubules. Here, we found that MAP7 family member MAP7D2 concentrates at the proximal axon, where it overlaps with the axon initial segment and interacts with kinesin-1. Depletion of MAP7D2 results in reduced axonal cargo entry and defects in axon development and neuronal migration. We propose a model in which MAP7D2 in the proximal axon locally promotes kinesin-1-mediated cargo entry into the axon.

Keywords: axon initial segment; kinesin; microtubule; microtubule-associated protein; transport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axonal Transport*
  • Axons / metabolism*
  • Binding Sites
  • COS Cells
  • Cells, Cultured
  • Chlorocebus aethiops
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Kinesin / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Protein Binding
  • Rats
  • Rats, Wistar

Substances

  • MAP7 protein, mouse
  • Microtubule-Associated Proteins
  • Kinesin