Tubulin rings: which way do they curve?

Curr Opin Struct Biol. 2003 Apr;13(2):256-61. doi: 10.1016/s0959-440x(03)00029-0.


Tubulin is known to exist in at least two main conformations: straight when bound to GTP or buried within the microtubule lattice, and curved when bound to GDP. The latter is most obvious during microtubule depolymerization, when protofilaments bend and peel off from microtubule ends. The curved, low-energy subunits form tantalizing ring structures in the presence of stabilizing divalent cations. Interestingly, cellular factors and antimitotic agents that act by depolymerizing microtubules can induce the formation of rings. In these rings, tubulin dimers generally appear kinked at the monomer-monomer interface, either to the same or to a lesser extent than at the dimer-dimer interface, with each agent giving rise to particular subtleties in the structures of the rings and the tubulin dimer itself that may reflect their distinctive mechanisms of action. How these kinks relate to what happens when the stored energy of GTP hydrolysis is released, freeing GDP*tubulin into an unconstrained state, remains an open question.

Publication types

  • Review

MeSH terms

  • Binding Sites
  • Depsipeptides
  • Guanosine Diphosphate / chemistry
  • Guanosine Diphosphate / metabolism
  • Guanosine Triphosphate / chemistry
  • Guanosine Triphosphate / metabolism
  • Microtubule Proteins*
  • Microtubules / chemistry*
  • Microtubules / metabolism
  • Microtubules / ultrastructure*
  • Models, Molecular*
  • Peptides, Cyclic / chemistry
  • Peptides, Cyclic / metabolism
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism
  • Protein Binding
  • Protein Conformation
  • Protein Denaturation
  • Protein Folding
  • Protein Serine-Threonine Kinases / chemistry
  • Protein Serine-Threonine Kinases / metabolism
  • Stathmin
  • Structure-Activity Relationship
  • Tubulin / chemistry*
  • Tubulin / metabolism
  • Tubulin / ultrastructure*


  • Depsipeptides
  • Microtubule Proteins
  • Peptides, Cyclic
  • Phosphoproteins
  • Stathmin
  • Tubulin
  • cryptophycin
  • Guanosine Diphosphate
  • Guanosine Triphosphate
  • Protein Serine-Threonine Kinases