Structural basis for isoform-specific kinesin-1 recognition of Y-acidic cargo adaptors

Elife. 2018 Oct 15;7:e38362. doi: 10.7554/eLife.38362.

Abstract

The light chains (KLCs) of the heterotetrameric microtubule motor kinesin-1, that bind to cargo adaptor proteins and regulate its activity, have a capacity to recognize short peptides via their tetratricopeptide repeat domains (KLCTPR). Here, using X-ray crystallography, we show how kinesin-1 recognizes a novel class of adaptor motifs that we call 'Y-acidic' (tyrosine flanked by acidic residues), in a KLC-isoform-specific manner. Binding specificities of Y-acidic motifs (present in JIP1 and in TorsinA) to KLC1TPR are distinct from those utilized for the recognition of W-acidic motifs, found in adaptors, that are KLC-isoform non-selective. However, a partial overlap on their receptor-binding sites implies that adaptors relying on Y-acidic and W-acidic motifs must act independently. We propose a model to explain why these two classes of motifs that bind to the concave surface of KLCTPR with similar low micromolar affinity can exhibit different capacities to promote kinesin-1 activity.

Keywords: X-ray crystallography; kinesin-1; molecular biophysics; molecular motor; mouse; structural biology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Fluorescence Polarization
  • HeLa Cells
  • Humans
  • Microtubule-Associated Proteins / chemistry*
  • Microtubule-Associated Proteins / metabolism*
  • Models, Molecular
  • Peptides / chemistry
  • Protein Binding
  • Protein Domains
  • Protein Isoforms / chemistry
  • Protein Isoforms / metabolism
  • Protein Structure, Secondary

Substances

  • Adaptor Proteins, Signal Transducing
  • Microtubule-Associated Proteins
  • Peptides
  • Protein Isoforms
  • kinesin light-chain proteins