Tau regulates the microtubule-dependent migration of glioblastoma cells via the Rho-ROCK signaling pathway

Abstract : The pathological significance of Tau in mechanisms driving cell migration in glioblastoma is unclear. Using shRNA approach to deplete microtubule-stabilizing Tau in U87 cells, we determined its impact on cytoskeletal coordination during migration. We demonstrated here that the motility of Tau-down-expressing cells (shTau) was significantly 36% lower than control cells. The shTau cells displayed weakly changed motility in the presence of nocodazole inhibiting microtubule formation. Such reduced motility of shTau cells was characterized by a 28% lower amount of microtubules bundles upon non-adhesive edges of the tails. In accord with Tau-stabilized microtubules required for cell movement, measurements of the front, body and rear section displacements of cells showed inefficient tail retraction in shTau cells. The tail retraction was restored by Y27632 inhibitor of the Rho-ROCK signaling. Moreover, we clearly identified that shTau cells displayed relocation of the active phosphoforms of p190-RhoGAP (inhibiting Rho-ROCK) and focal adhesion kinase (FAK) in cell bodies. In conclusion, our findings indicate that Tau governs the remodeling of microtubule and actin networks in the phase of retraction of the tail of cells necessary for effective migration.