細胞分裂
Cell division orientation is of major importance for tissue architecture, cell fates and morphogenesis. Cells tend to divide along their long axis according to the so-called Hertwig rule. The axis of cell division is determined by the orientation of the spindle apparatus. Cells divide along the line connecting two centrosomes of the spindle apparatus. After formation, the spindle apparatus undergoes rotation inside the cell. The astral microtubules originating from centrosomes reach the cell membrane where they are pulled towards specific cortical clues. "In vitro", the distribution of cortical clues is set up by the adhesive pattern. "In vivo" polarity cues are determined by localization of Tricellular junctions localized at cell vertices. The spatial distribution of cortical clues leads to the force field that determine final spindle apparatus orientation and the subsequent orientation of cell division.