- Plasma membrane depolarization-activated calcium channels, stimulated by microtubule-depolymerizing drugs in wild-type Arabidopsis thaliana protoplasts, display constitutively large activities and a longer half-life in ton 2 mutant cells affected in the organization of cortical microtubules. Thion, L., Mazars, C., Nacry, P., Bouchez, D., Moreau, M., Ranjeva, R., Thuleau, P. Plant J. (1998)