A Developmentally Regulated Two-Step Process Generates a Noncentrosomal Microtubule Network in Drosophila Tracheal Cells

SummaryMicrotubules (MTs) are essential for many cell features, such as polarity, motility, shape, and vesicle trafficking. Therefore, in a multicellular organism, their organization differs between cell types and during development; however, the control of this process remains elusive. Here, we show that during Drosophila tracheal morphogenesis, MT reorganization is coupled to relocalization of the microtubule organizing centers (MTOC) components from the centrosome to the apical cell domain from where MTs then grow. We reveal that this process is controlled by the trachealess patterning gene in a two-step mechanism. MTOC components are first released from the centrosome by the activity of the MT-severing protein Spastin, and then anchored apically through the transmembrane protein Piopio. We further show that these changes are essential for tracheal development, thus stressing the functional relevance of MT reorganization for morphogenesis.

► During fly tracheal development, microtubule organizing center (MTOC) move apically
► Regulated expression of MT-severing Spastin releases MTOCs from centrosomes
► Transmembrane Piopio protein helps anchor released MTOCs to the apical cell cortex
► Timed control of MTOC relocalization is required for epithelial morphogenesis in vivo