Precise inheritance of organelles during mitosis ensures the proper organisation and function of daughter cells. Inheritance of the Golgi complex, a single copy organelle, requires its disassembly before mitosis; Golgi disassembly is driven by mitotic inhibition of COPII-dependent export of proteins from endoplasmic reticulum exit sites (ERESs) to the Golgi. Helen Hughes and David Stephens have been investigating how ERESs are restored at the end of mitosis and, on page 4032, they report that Sec16A – the major human orthologue of Sec16, which defines the site of COPII vesicle budding in yeast – defines the site at which COPII-dependent budding reinitiates after mitosis. Using quantitative 4D imaging of HeLa cells stably expressing fluorescently labelled Sec16A, the authors show that, unlike all other COPII components, Sec16A remains associated with ERESs throughout mitosis. Moreover, Sec16A localisation is coincident with the reappearance of COPII puncta on mitotic exit. Hughes and Stephens suggest, therefore, that Sec16A provides a template for the assembly of functional export domains in anaphase, thus ensuring that the internal architecture of the cell is restored quickly and effectively on exit from mitosis.

© 2010.
2010