Open Close
Caviglia, S., Brankatschk, M., Fischer, E.J., Eaton, S., Luschnig, S. (2016). Staccato/Unc-13-4 controls secretory lysosome-mediated lumen fusion during epithelial tube anastomosis.  Nat. Cell Biol. 18(7): 727--739.
FlyBase ID
Publication Type
Research paper

A crucial yet ill-defined step during the development of tubular networks, such as the vasculature, is the formation of connections (anastomoses) between pre-existing lumenized tubes. By studying tracheal tube anastomosis in Drosophila melanogaster, we uncovered a key role of secretory lysosome-related organelle (LRO) trafficking in lumen fusion. We identified the conserved calcium-binding protein Unc-13-4/Staccato (Stac) and the GTPase Rab39 as critical regulators of this process. Stac and Rab39 accumulate on dynamic vesicles, which form exclusively in fusion tip cells, move in a dynein-dependent manner, and contain late-endosomal, lysosomal, and SNARE components characteristic of LROs. The GTPase Arl3 is necessary and sufficient for Stac LRO formation and promotes Stac-dependent intracellular fusion of juxtaposed apical plasma membranes, thereby forming a transcellular lumen. Concomitantly, calcium is released locally from ER exit sites and apical membrane-associated calcium increases. We propose that calcium-dependent focused activation of LRO exocytosis restricts lumen fusion to appropriate domains within tip cells.

PubMed ID
PubMed Central ID
Related Publication(s)

Mapping the molecular steps of secretory-lysosome-driven tracheal tube fusion.
Aydogan et al., 2016, Nat. Cell Biol. 18(7): 720--722 [FBrf0232826]

Associated Information
Associated Files
Other Information
Secondary IDs
    Language of Publication
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Nat. Cell Biol.
    Nature Cell Biology
    Publication Year
    1465-7392 1476-4679
    Data From Reference
    Aberrations (1)
    Alleles (50)
    Genes (34)
    Polypeptides (1)
    Natural transposons (2)
    Insertions (13)
    Experimental Tools (11)
    Transgenic Constructs (19)