The preprophase band of microtubules controls the robustness of division orientation in plants ($)

Every student of plant cell biology learns that the future plane of cell division is marked very early in mitosis by the preprophase band (PPB), a band of microtubules that forms around the periphery of the cell. Prior experimental studies have suggested that the PPB is necessary for proper placement of the mitotic spindle and the division plane. Schaefer et al. examined trm mutants (TON1 Recruiting Motif) in which the PPB fails to form; TON1 is part of a protein network involved in microtubule dynamics. In these PPB-deficient mutants, the average plane of cell division is indistinguishable from wild type, but there is greater variance; “such effects on variance without affecting the mean are characteristic of a process acting as a stabilizer rather than as a primary determinant,” thus suggesting a new interpretation of the role of the PPB. Science 10.1126/science.aal3016