Differential interaction of synthetic peptides from the carboxyl-terminal regulatory domain of tubulin with microtubule-associated proteins.
In previous studies we have demonstrated that a 4-kd tubulin fragment, including amino acid residues from Phe418 to Glu450 in alpha-subunit and Phe408-Ala445 of the beta-sequence, plays a major role in controlling tubulin interactions leading to microtubule assembly. The 4-kd carboxyl-terminal domain also constitutes an essential domain for the interaction of microtubule-associated proteins (MAPs). Removal of the 4-kd fragment facilitates tubulin self-association and renders the assembly MAP-independent. In order to define the substructure of the tubulin domain for MAP interaction, we have examined the binding of 3H-acetylated C-terminal peptides to MAP-2 and tau. Two synthetic peptides from the low-homology region within the 4-kd domain alpha (430-441) and beta (422-434) and the peptide, alpha (401-410) of the high-homology region adjacent to the 4-kd domain, were analyzed with respect to MAP interaction. The binding data showed a relatively strong interaction of MAP-2 with the beta (422-434) peptide and a weaker interaction of both MAPs components with alpha (430-441) tubulin peptide as analyzed by Airfuge ultracentrifugation and zone filtration chromatography. The homologous alpha (401-410) peptide did not bind to either MAP-2 or tau. Equilibrium dialysis experiments showed a co-operative binding of beta (422-434) peptide to multiple sites in tau. The alpha (430-441) peptide exhibited a stronger interaction for tau as compared with MAP-2.(ABSTRACT TRUNCATED AT 250 WORDS)
Maccioni
R B
RB
Department of Biochemistry, Biophysics and Genetics, University of Colorado Health Sciences Center, Denver 80262.
Rivas
C I
CI
Vera
J C
JC
D000107:Acetylation; D000818:Animals; D001921:Brain / Q000378:metabolism; D002417:Cattle; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009842:Oligopeptides / Q000138:chemical synthesis; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D014404:Tubulin / Q000378:metabolism*
D008869:Microtubule-Associated Proteins; D009842:Oligopeptides; D010446:Peptide Fragments; D014404:Tubulin