A putative beta-tubulin phosphate-binding motif is involved in lateral microtubule protofilament interactions.
We have investigated the role of a putative GTP-binding beta-tubulin motif in microtubule polymerization. A peptide containing residues 126-142 of the beta-tubulin subunit (peptide G) was synthesised and an antibody against it raised. Peptide G prevents the binding of GTP to tubulin and also microtubule polymerization but not the formation of vinblastine-induced tubulin spirals, suggesting that it may prevent lateral but not longitudinal tubulin-tubulin interactions. The antibody to peptide G shows little reaction with the interphase microtubule network, mitotic spindles or midbody of cultured cells, whereas it clearly reacts with vinblastine-induced paracrystals. These results suggest that this putative phosphate-binding site present in beta-tubulin could be involved in the lateral tubulin-tubulin interactions along the microtubule structure.
Pérez
M
M
Centro de Biología Molecular (CSIC-UAM) Facultad de Ciencias, Universidad Autónoma de Madrid, Spain.
Aloria
K
K
Zabala
J C
JC
Avila
J
J
D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology; D001665:Binding Sites; D001667:Binding, Competitive; D019281:Dimerization; D005455:Fluorescent Antibody Technique; D006160:Guanosine Triphosphate / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D011485:Protein Binding; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism*; D014747:Vinblastine / Q000378:metabolism
D000906:Antibodies; D010446:Peptide Fragments; D010710:Phosphates; D014404:Tubulin; D014747:Vinblastine; D006160:Guanosine Triphosphate