Confocal investigation on colocalization between tubulin posttranslational modifications and associated proteins in rat C6 glioma cells

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 codistribution
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.