Branching at the single cell level; a tale of centrosomes and microtubules
Jul. 18, 2018 16:00 - 17:00
DB Bldg. SeminarRoom A7F
Sofia J. Araújo
Department of Genetics, Microbiology and Statistics, University of Barcelona
Branching networks are a very common feature of multicellular animals and underlie the formation and function of numerous organs including the nervous system, the respiratory system, the vasculature and many internal glands. These networks vary from subcellular structures such as dendritic trees to large multicellular tissues such as the lungs. The production of branched structures by single cells, which has been better described in neurons and in cells of the respiratory and vascular systems, involves complex cytoskeletal remodelling events. In Drosophila, tracheal system terminal cells (TCs) and nervous system dendrites are models for these subcellular branching processes. During tracheal embryonic development, the generation of subcellular branches is accompanied by lumen formation and is characterized by extensive remodelling of the microtubule network and actin cytoskeleton, followed by vesicular transport and membrane dynamics. We have recently shown that centrosomes are key players in the initiation of this subcellular lumen formation where they act as microtubule organizing centres (MTOCs) (Ricolo, et al. Cur. Biol. 2016). However, not much is known on the events that trigger the dynamic elongation of these subcellular branches or what makes them choose a particular trajectory within the cytoplasm of the TC. We have identified that the spectraplakin Shortstop (Shot) is involved in the microtubule stabilisation events that lead to the formation and extension of the subcellular lumen. We observed that an excess of Shot induces more branching points in the embryonic tracheal TC leading to cells with extra subcellular lumina and that a shot loss-of-function leads to cells deficient in de novo subcellular lumen formation.