ABSTRACT
The organisation of microtubules rich in post-transiationaily modified α-tubulin has been investigated in a fibroblast cell line (NIH–3T3–T15) that can be reversibly transformed. An immunofluorescence microscopy study of the static non-trans-formed cells has revealed a central distribution of wavy microtubules showing post-translational modifications. When transformed there is a marked increase in cell motility and the appearance of long thin cytoplasmic ‘tails’. These tails have been found to contain conspicuous bundles of post-trans-lationally modified microtubules that run down the length of the processes and terminate close to the plasmalemma. Both detyrosinated and acetylated α-tubulin are present as major species in these modified microtubules. Such a pattern of modified microtubules is only occasionally seen in the untransformed NIH–3T3–T15 cells. We have also found them to be present in other transformed fibroblast lines. The presence of bundles of micro-tubules rich in modified α-tubulin in the cell tails is correlated with a marked reduction in the numbers of F-actin stress fibres. The possible role of these modified stable microtubules in cell motility is discussed.
