Trafficking through COPII stabilises cell polarity and drives secretion during Drosophila epidermal differentiation.
BACKGROUND
The differentiation of an extracellular matrix (ECM) at the apical side of epithelial cells implies massive polarised secretion and membrane trafficking. An epithelial cell is hence engaged in coordinating secretion and cell polarity for a correct and efficient ECM formation.


RESULTS
We are studying the molecular mechanisms that Drosophila tracheal and epidermal cells deploy to form their specific apical ECM during differentiation. In this work we demonstrate that the two genetically identified factors haunted and ghost are essential for polarity maintenance, membrane topology as well as for secretion of the tracheal luminal matrix and the cuticle. We show that they code for the Drosophila COPII vesicle-coating components Sec23 and Sec24, respectively, that organise vesicle transport from the ER to the Golgi apparatus.


CONCLUSIONS
Taken together, epithelial differentiation during Drosophila embryogenesis is a concerted action of ECM formation, plasma membrane remodelling and maintenance of cell polarity that all three rely mainly, if not absolutely, on the canonical secretory pathway from the ER over the Golgi apparatus to the plasma membrane. Our results indicate that COPII vesicles constitute a central hub for these processes.
Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany.
Michaela
M
Norum
Erika
E
Tång
Tina
T
Chavoshi
Heinz
H
Schwarz
Dirk
D
Linke
Anne
A
Uv
Bernard
B
Moussian
D000818:Animals; D001485:Basement Membrane / Q000378:metabolism; D001692:Biological Transport; D022181:COP-Coated Vesicles / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D016764:Cell Polarity; D048430:Cell Shape; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D000078404:Epidermal Cells; D017353:Gene Deletion; D017344:Genes, Insect / Q000235:genetics; D007814:Larva / Q000166:cytology; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D014132:Trachea / Q000166:cytology / Q000378:metabolism
D029721:Drosophila Proteins