Confocal investigation on colocalization between tubulin posttranslational modifications and associated proteins in...

Glioblastoma multiforme is the most lethal brain tumor. In the study of mechanisms underlying its development attention has been paid to the microtubular network of its cells, mainly on βIII tubulin, considered as a marker of malignancy. In the present work, we chose to investigate the tubulin code in glioblastoma cells, analyzing the degree of interaction between tubulin post-translational modifications and different proteins associated with them. The pattern of diverse associated proteins such as EB-1, CLIP-170 and kinesin-1 and their degree of co-distribution with the most abundant post-translational tubulin modifications (tyrosination, acetylation and polyglutamylation) were evaluated. Through immunofluorescence we have shown that EB-1, CLIP-170 and kinesin-1 were well detectable in glioblastoma cells. The double fluorescence and colocalization index between the post-translational modifications of tubulin and associated proteins showed that tyrosinated α-tubulin has significantly high affinity with EB-1, CLIP-170 and kinesin-1, while for acetylated and polyglutamylated tubulin, the degree of interaction with the three associated proteins evaluated was less apparent. Data presented in this paper underline the importance of a thorough analysis of the microtubular mechanics in glioblastoma cells. This may suggest new experimental therapeutic approaches able to act more selectively on the microtubular network of cells in this type of cancer.