Premium
The stability of cortical microtubules depends on their orientation
Author(s) -
Wiesler Bodo,
Wang QiYan,
Nick Peter
Publication year - 2002
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2002.01489.x
Subject(s) - microtubule , auxin , coleoptile , tubulin , biology , microbiology and biotechnology , cleavage (geology) , biophysics , cytoskeleton , biochemistry , cell , paleontology , fracture (geology) , gene
Summary Auxin controls the orientation of cortical microtubules in maize coleoptile segments. We used tyrosinylated α‐tubulin as a marker to assess auxin‐dependent changes in microtubule turnover. Auxin‐induced tyrosinylated α‐tubulin, correlated with an elevated sensitivity of growth to antimicrotubular compounds such as ethyl‐ N ‐phenylcarbamate (EPC). We determined the affinity of α‐tubulin to EPC and found that it was dramatically increased when the tubulin was de‐tyrosinylated. By proteolytic cleavage of the carboxy terminal tyrosine, such an increased affinity could be induced in vitro . Thus, the auxin‐induced sensitivity of growth to EPC is not caused by an increased affinity for this inhibitor, but caused by a reduced microtubule turnover. Double visualization assays revealed that the transverse microtubules induced by auxin consist predominantly of tyrosinylated α‐tubulin, whereas the longitudinal microtubules induced by auxin depletion contain de‐tyrosinylated α‐tubulin. The results are discussed in terms of direction‐dependent differences in the lifetime of microtubules.