Quantifying Polarization Factor of MCF7 microtubules in the presence of Tau Protein.

Microtubules are one of the intracellular components that consist of alpha and beta tubulin. The C-terminal tails of tubulin carry some negative electric charges, therefore, polymerized microtubules are negatively charged. The dielectric specifications of neuronal microtubules have been evaluated in several reported studies. However, our knowledge about dielectric factors of non-neuronal microtubules is still limited.
In our study, we quantified the normalized polarization coefficient of Tau-MCF7 microtubules by implementing the electro-orientation method. The result was then compared with the one we previously reported for MCF7 microtubules in the absence of Tau protein. This study is significant, as MCF7 microtubules are structurally different from neuronal microtubules in terms of the distribution of beta tubulin isotypes. The polarization factor and, consequently, negative charge of those microtubules is smaller than MCF7 polymerized from MCF7 tubulin. This can potentially be an underlying mechanism for many intracellular functions.