Putative Roles of Planar Cell Polarity Proteins in the Establishment and Regulation of Asymmetric Cell Division

Abstract

During animal development, cells need to grow, divide and differentiate according to the body plan. To do so, cells utilize complex mechanisms to polarize themselves asymmetrically on the apical-basal axis, but also within the plane of the tissue, known as planar cell polarity (PCP). In order to establish an axis for oriented division, asymmetrically segregate cell fate determinants and orient the mitotic spindle, the cells use PCP to align themselves with the body plan. How PCP regulates asymmetric division and spindle orientation is unknown at the moment. Recent data suggest an important role for the PCP core proteins Frizzled, Van Gogh/Strabismus and Flamingo/Starry Night in aligning the spindle to the axis of division. However, the exact mechanism remains to be resolved. In this thesis, current models on how cells establish polarity, PCP and orient the mitotic spindle to ensure correct asymmetric division will be reviewed. Furthermore, current important questions in the field of PCP research nowadays will be discussed.