Microtubule cytoskeleton perturbation induced by taxol and colchicine affects chaperonin containing TCP-1 (CCT) subunit gene expression in Tetrahymena cells

Abstract

We report the existence of a CCT epsilon subunit gene that encodes subunit epsilon of the chaperonin CCT (chaperonin containing TCP-1) in Tetrahymena pyriformis. This work focuses on the study of the effects of the microtubule polymerizing agent taxol and the depolymerizing agent colchicine on microtubule dynamics and their role in the regulation of tubulin and CCT subunit genes. Under taxol treatment some TpCCT and tubulin genes are distinctly expressed until 30 min of treatment. Cytoplasmic TpCCT mRNA levels slightly decrease while tubulin transcripts are increasing. In colchicine treated cells TpCCT and tubulin transcripts decrease in the initial 30 min of treatment and then start to increase. However, both antimitotic agents induce TpCCT and tubulin gene transcription. This induction does not correlate with increased steady-state levels of TpCCT proteins and seems to be necessary to replete cytoplasmic TpCCT mRNAs. Moreover, we found that TpCCT epsilon and TpCCT alpha but not TpCCT eta are present in the insoluble fraction after a postmitochondrial fractionation that contains components of the ciliate cortex structure, basal bodies and cilia. This suggests that some TpCCT subunits may be associated with these structures. The association of TpCCT epsilon subunit is stimulated either by taxol or colchicine treatment. These observations support the idea that CCT subunits could have additional roles in vivo.

Possible involvement of CCT5, RGS3, and YKT6 genes up-regulated in p53-mutated tumors in resistance to docetaxel in human breast cancers

“…The complex folds the various proteins including the btubulin. Microtubule cytoskeleton perturbation induced by paclitaxel is reported to increase CCT5 expression in Tetrahymena cells [32]. We also found an increase in CCT5 protein after docetaxel treatment.…”

CCTη, a Novel Soluble Guanylyl Cyclase-interacting Protein

“…Interestingly, the subunits of CCT do not always display the same cellular localization, e.g. CCT has been specifically detected in the soluble fraction of Tetrahymena homogenate, whereas CCT␣ and CCT⑀ were detected only in the particulate fraction associated with microtubules (17,18). This finding suggests that the subunits of the CCT complex do not necessarily always form an oligomer or that this oligomer is not always composed of all eight subunits.…”

Effects of taxol treatment on the microtubular system and mitochondria of Tetrahymena

“…Taxol act directly on mitochondria isolated from human neuroblastoma cells (Andre et al, 2002); exerts rapid effects on the cytosolic Ca 2þ signal via the opening of the mitochondrial permeability transition pore (Kidd et al, 2002). In Tetrahymena taxol influences tubulin genes as well as chaperonin genes (Casalou et al, 2001). In Trichomonas it influences hydrogenosomes, which had abnormal size and shape and autophage vacuoles appeared containing large amount of microtubules (Madeiro da Costa and Benchimol, 2004).…”