Model for stathmin/OP18 Binding to Tubulin

EMBO J. 2000 Jan 17;19(2):213-22. doi: 10.1093/emboj/19.2.213.

Abstract

Stathmin/OP18 is a regulatory phosphoprotein that controls microtubule (MT) dynamics. The protein does not have a defined three-dimensional structure, although it contains three distinct regions (an unstructured N-terminus, N: 1-44; a region with high helix propensity, H 1: 44-89; and a region with low helix propensity, H 2: 90-142). The full protein and a combination of H 1 and H 2 inhibits tubulin polymerization, while the combination of H 1 and the N-terminus is less efficient. None of the individual three regions alone are functional in this respect. However, all of them cross-link to alpha-tubulin, but only full-length stathmin produces high-molecular-weight products. Mass spectrometry analysis of alpha-tubulin-stathmin/OP18 and its truncation products shows that full-length stathmin/OP18 binds to the region around helix 10 of alpha-tubulin, a region that is involved in longitudinal interactions in the MT, sequestering the dimer and possibly linking two tubulin heterodimers. In the absence of the N-terminus, stathmin/OP18 binds to only one molecule of alpha-tubulin, at the top of the free tubulin heterodimer, preventing polymerization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • Humans
  • Microtubule Proteins*
  • Microtubules / ultrastructure
  • Models, Molecular
  • Phosphoproteins / chemistry*
  • Phosphoproteins / metabolism*
  • Protein Denaturation
  • Protein Structure, Secondary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Stathmin
  • Thermodynamics
  • Tubulin / chemistry*
  • Tubulin / metabolism*

Substances

  • Microtubule Proteins
  • Phosphoproteins
  • Recombinant Proteins
  • STMN1 protein, human
  • Stathmin
  • Tubulin