Common and distinct tubulin binding sites for microtubule-associated proteins.
A specific binding assay was developed that monitors the interaction of 125I-labeled microtubule-associated proteins (MAPs) with tubulin or its fragments bound to nitrocellulose membrane. To identify the tubulin-binding domains for MAPs we have examined the binding of rat brain 125I-labeled MAP2 or 125I-labeled tau factors to 60 peptides derived from porcine alpha- and beta-tubulin. MAP2 and tau factors specifically interacted with two peptides derived from the carboxyl-terminal region of beta-tubulin, which are located between positions 392-445 and 416-445. In addition, there is a distinct tau-binding site at the amino-terminal region of alpha-tubulin. tau factors but not MAP2 displayed strong interaction with a peptide derived from the amino-terminal domain of alpha-tubulin between positions 1 and 75. To narrow down the location of the beta-tubulin binding site that is common to MAP2 and tau factors, we have synthesized five peptides that are homologous to the corresponding sequence from the porcine or rat carboxyl-terminal region. Binding studies with the synthetic peptides suggest that amino acid residues 434-440 of beta-tubulin are crucial for the interaction of MAP2 and tau factors.
Littauer
U Z
UZ
Giveon
D
D
Thierauf
M
M
Ginzburg
I
I
Ponstingl
H
H
D000818:Animals; D001665:Binding Sites; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008970:Molecular Weight; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D013552:Swine; D014404:Tubulin / Q000378:metabolism*
D008869:Microtubule-Associated Proteins; D009842:Oligopeptides; D010446:Peptide Fragments; D014404:Tubulin