The role of tetraspanins in plant cell division orientation
How do plant cells decide in which direction to divide? Despite many years of research, we still do not know. This is remarkable, because the selection of the division plane is one of the most important developmental decisions a plant cell has to make throughout its growth. My host lab recently identified the transcriptional pathway that regulates the switch from anticlinal to periclinal cell divisions in the developing Arabidopsis root vascular tissues. However, the executors that translate this transcriptional program into division plane selection remain elusive. By overlap analysis of unpublished bulk- and single-cell-RNA-sequencing datasets generated recently in my host lab, I found that the TETRASPANIN (TET) genes are prime candidates for such executors of cell division orientation. The TET family is conserved throughout eukaryotes, and in animals, TETs act as molecular scaffolds at the plasma membrane and play important roles in the regulation of membrane trafficking, signaling, cell morphogenesis and other vital processes. In contrast, in plants, the molecular functions of TETs are not known, but their putative scaffolding function provides a plausible mechanism for the regulation of cell division orientation through organizing proteins at the cortical division zone. In DIVISION BELL, I will unravel the molecular function of plant TETs and validate their role in the regulation of cell division orientation during root vascular development. To reach this goal, I will combine my expertise in cell biology and bioimaging with state of the art genome-editing techniques, cutting-edge proteomics and top-notch imaging approaches available at the host institute.  This innovative approach will allow me to shed light on the mechanism of cell division orientation regulation by the TETRASPANIN proteins, with the potential to make major conceptual advances in this thrilling field of plant science.