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The `assembly‐promoting sequence region' of microtubule‐associated protein 4 failed to promote microtubule assembly
Author(s) -
Katsuki Miho,
Tokuraku Kiyotaka,
Nakagawa Hiroyuki,
Murofushi Hiromu,
Kotani Susumu
Publication year - 1997
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/s0014-5793(97)01342-2
Subject(s) - microtubule , tubulin , sequence (biology) , biophysics , microtubule associated protein , fragment (logic) , escherichia coli , microbiology and biotechnology , biology , chemistry , biochemistry , gene , computer science , programming language
In order to study the function of the bovine MAP4 microtubule‐binding domain (the assembly‐promoting (AP) sequence region), a fragment corresponding to the AP sequence region was prepared using an Escherichia coli expression system. When the fragment was mixed with purified tubulin at 37°C, the fragment caused a time‐ and dose‐dependent turbidity increase, and the fragment bound to tubulin. However, the products were cold‐stable, and amorphous aggregates were observed by electron microscopy. Using axonemes as the seeds for microtubule assembly, the microtubule‐elongating activity of the fragment was examined. A dose‐dependent turbidity increase of the sample was observed, and electron microscopic observation revealed that microtubules were dose‐dependently elongated from the axonemes. Consequently, the AP sequence region does not nucleate microtubules, but elongates them.