Maintaining asymmetry in cell division

Promoting asymmetric division through microtubule dynamics establishes cell fate In multicellular organisms, cell division contributes to the generation of specialized cells. In walled organisms such as plants, the orientation of the division plane by which two daughter cells separate is of special importance because cells are embedded in a matrix and cannot relocate. To define the future cell division zone before mitosis, plants have evolved a specific structure called the preprophase band (PPB), which is composed of microtubules. In the context of asymmetric cell division, a polar domain is established at the plasma membrane to allow the differentiation of one of the daughter cells while maintaining a stem cell population. How plant cells establish the polar domain remains enigmatic. On page 54 of this issue, Muroyama et al. (1) reveal that a polarized destabilization of microtubules demarcates a region of the plant cell as incompatible with microtubule PPB establishment, thereby orienting asymmetric cell division and guiding the development of stomata (pores for gas exchange).