The integration of positional sensing with cell division and wall orientation is pivotal for maintaining correct plant stem cell control, growth and development. In this issue, Liang et al. (pp. 1855–1866) uncover one of the factors involved in this process, and show that early Arabidopsis embryos defective in DEK1 calpain function exhibit altered expression of developmental markers related to axis organization, cell identity and meristem functions, aberrant microtubule patterns, and misshapen cells. The data suggest that DEK1 controls microtubule-directed cell wall orientation during cell division, and imply a general function for the phytocalpain in microtubule organization.