GTP-dependent conformational changes associated with the functional switch between Galpha and cross-linking activities in brain-derived tissue transglutaminase

J Mol Biol. 1998 Oct 2;282(4):713-20. doi: 10.1006/jmbi.1998.2052.


GTP and Ca2+, two well-known modulators of intracellular signaling pathways, control a structural/functional switch between two vital and mutually exclusive activities, cross-linking and Galpha activity, in the same enzyme. The enzyme, a brain-derived tissue-type transglutaminase (TGase), was recently cloned by us in two forms, one of which (s-TGN) lacks a C-terminal region that is present in the other (l-TGN). Immunoreaction with antibodies directed against a peptide present in the C-terminus of l-TGN but missing in s-TGN suggested that this site, which is located in the C-terminal fourth domain, undergoes conformational changes as a result of interaction between l-TGN and GTP. Site-directed mutagenesis suggested that the third domain is involved in mediating the inhibition of the cross-linking activity. These results were supported by molecular modeling, which further suggested that domains III and IV both participate in conformational changes leading to the functional switch between the Ca2+-dependent cross-linking activity and the Galpha activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites / drug effects
  • Brain / cytology
  • Brain / enzymology*
  • Calcium / metabolism
  • Calcium / pharmacology
  • Cell Line
  • Cross-Linking Reagents / chemistry
  • Cross-Linking Reagents / metabolism*
  • GTP Phosphohydrolases / chemistry*
  • GTP Phosphohydrolases / genetics
  • GTP Phosphohydrolases / metabolism
  • GTP-Binding Proteins / chemistry
  • GTP-Binding Proteins / metabolism*
  • Guanosine Triphosphate / metabolism*
  • Guanosine Triphosphate / pharmacology
  • Humans
  • Kinetics
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Mutation
  • Precipitin Tests
  • Protein Binding / drug effects
  • Protein Conformation / drug effects
  • Protein Glutamine gamma Glutamyltransferase 2
  • Rats
  • Structure-Activity Relationship
  • Transfection
  • Transglutaminases / chemistry*
  • Transglutaminases / genetics
  • Transglutaminases / metabolism


  • Cross-Linking Reagents
  • Guanosine Triphosphate
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • GTP Phosphohydrolases
  • GTP-Binding Proteins
  • Calcium