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Role of the carboxy terminal region of β tubulin on microtubule dynamics through its interaction with the GTP phosphate binding region
Author(s) -
Padilla Rodolfo,
Otin Carlos López,
Serrano Luis,
Avila Jesús
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81067-a
Subject(s) - gtp' , tubulin , microtubule , microtubule associated protein , binding site , biophysics , chemistry , protein subunit , binding domain , biology , microbiology and biotechnology , biochemistry , enzyme , gene
The dynamic instability of microtubules depends on the GTP binding to tubulin, the rate of hydrolysis of GTP bound to tubulin molecules, at the microtubule caps, and on the affinity and exchange rate of tubulin for GTP versus GDP. It has been demonstrated that the binding of microtubule‐associated proteins (MAPs) such as Tau or MAP2 notably enhances microtubule stability in vivo. These MAPs bind to the tubulin carboxy terminal domain. Consequently, an attractive hypothesis to explain the modulation of microtubule dynamics by MAPs is that the carboxy terminal domain of tubulin interacts with a region close to the GTP binding site, preventing the binding of GTP or exchange of GDP for GTP. By carrying out a combined analysis of crosslinking and limited proteolysis, an intramolecular interaction between the carboxy terminus and the tubulin region containing the GTP binding site in β tubulin has been observed. It is proposed that this interaction modifies the binding of GTP to the tubulin β‐subunit and, therefore, affects tubulin assembly dynamics. This suggests a molecular explanation for the effect of MAPs in facilitating tubulin polymerization through the regulation of the interaction of GTP.