Key interaction modes of dynamic +TIP networks

Mol Cell. 2006 Sep 1;23(5):663-71. doi: 10.1016/j.molcel.2006.07.013.

Abstract

Dynamic microtubule plus-end tracking protein (+TIP) networks are implicated in all functions of microtubules, but the molecular determinants of their interactions are largely unknown. Here, we have explored key binding modes of +TIPs by analyzing the interactions between selected CAP-Gly, EB-like, and carboxy-terminal EEY/F-COO(-) sequence motifs. X-ray crystallography and biophysical binding studies demonstrate that the beta2-beta3 loop of CAP-Gly domains determines EB-like motif binding specificity. They further show how CAP-Gly domains serve as recognition domains for EEY/F-COO(-) motifs, which represent characteristic and functionally important sequence elements in EB, CLIP-170, and alpha-tubulin. Our findings provide a molecular basis for understanding the modular interaction modes between alpha-tubulin, CLIPs, EB proteins, and the dynactin-dynein motor complex and suggest that multiple low-affinity binding sites in different combinations control dynamic +TIP networks at microtubule ends. They further offer insights into the structural consequences of genetic CAP-Gly domain defects found in severe human disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism
  • Crystallography, X-Ray
  • Cytoskeletal Proteins / chemistry
  • Cytoskeletal Proteins / metabolism
  • Humans
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / metabolism*
  • Models, Biological
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary

Substances

  • Bacterial Proteins
  • Cytoskeletal Proteins
  • EB1 microtubule binding proteins
  • Microtubule-Associated Proteins

Associated data

  • PDB/2HKN
  • PDB/2HKQ
  • PDB/2HL3
  • PDB/2HL5