Interaction of microtubules with the actin cytoskeleton via cross-talk of EB1-containing plus TIPs and γ-actin in epithelial cells

Actin microfilaments and microtubules are both highly dynamic cytoskeleton components implicated in a wide range of intracellular processes as well as cell-cell and cell-substrate interactions. The interactions of actin filaments with the microtubule system play an important role in the assembly and maintenance of 3D cell structure. Here we demonstrate that cytoplasmic actins are differentially distributed in relation to the microtubule system. LSM, 3D-SIM, proximity ligation assay (PLA) and co-immunoprecipitation methods applied in combination with selective depletion of beta-or gamma-cytoplasmic actins revealed a selective interaction between microtubules and gamma-, but not beta-cytoplasmic actin via the microtubule +TIPs protein EB1. EB1-positive comet distribution analysis and quantification have shown more effective microtubule growth in the absence of beta-actin. Our data represent the first demonstration that microtubule +TIPs protein EB1 interacts mainly with gamma-cytoplasmic actin in epithelial cells.