Calmodulin binds to a tubulin binding site of the microtubule-associated protein tau.
Previous studies have demonstrated that the microtubule-associated proteins MAP-2 and tau interact selectively with common binding domains on tubulin defined by the low-homology segments alpha (430-441) and beta (422-434). It has been also indicated that the synthetic peptide VRSKIGSTENLKHQPGGG corresponding to the first tau repetitive sequence represents a tubulin binding ... domain on tau. The present studies show that the calcium-binding protein calmodulin interacts with a tubulin binding site on tau defined by the second repetitive sequence VTSKCGSLGNIHHKPGGG. It was shown that both tubulin and calmodulin bind to tau peptide-Sepharose affinity column. Binding of calmodulin occurs in the presence of 1 mM Ca 2+ and it can be eluted from the column with 4 mM EGTA. These findings provide new insights into the regulation of microtubule assembly, since Ca2+/calmodulin inhibition of tubulin polymerization into microtubules could be mediated by the direct binding of calmodulin to tau, thus preventing the interaction of this latter protein with tubulin.
Mesh Terms:
Amino Acid Sequence, Animals, Binding Sites, Brain Chemistry, Calcium, Calmodulin, Humans, Mice, Microtubule-Associated Proteins, Molecular Sequence Data, Sequence Homology, Nucleic Acid, Tubulin, tau Proteins
Amino Acid Sequence, Animals, Binding Sites, Brain Chemistry, Calcium, Calmodulin, Humans, Mice, Microtubule-Associated Proteins, Molecular Sequence Data, Sequence Homology, Nucleic Acid, Tubulin, tau Proteins
Mol. Cell. Biochem.
Date: Sep. 03, 1990
PubMed ID: 2123288
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