Cells that lack katanin (KO) have more microtubules (green) in the cell body than do normal cells (WT).
All microtubules are not created equal. In Tetrahymena, for example, the polymers come in many flavors, including ciliary extensions, an internal network, and cortical bundles. These subsets, the new results indicate, are differentially affected by katanin activity.
After knocking out Tetrahymena katanin, the authors found that cilia were missing their central microtubules and had shorter outer doublets. Cortical bundles and internal microtubules, by contrast, were more abundant and unusually stable. These inner polymers were more heavily laden with posttranslational modifications, including acetylation, glutamylation, and glycylation.
These modifications normally increase as microtubules age, so their accumulation might be a simple...
