scholarly journals Ride the wave: Retrograde trafficking becomes Ca2+ dependent with BAIAP3

2017 ◽  
Vol 216 (7) ◽  
pp. 1887-1889 ◽  
Author(s):  
Jakob B. Sørensen
Keyword(s):  
Angiogenesis Inhibitor ◽  
Secretory Vesicle ◽  
Vesicle Formation ◽  
Retrograde Trafficking ◽  
Trans Golgi Network ◽  
Cell Biol ◽  
Golgi Network

The functions of four of the five proteins in the mammalian uncoordinated-13 (Munc13) family have been identified as priming factors in SNARE-dependent exocytosis. In this issue, Zhang et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201702099) show that the fifth member, BAIAP3 (brain-specific angiogenesis inhibitor I–associated protein 3), acts in retrograde trafficking by returning secretory vesicle material to the trans-Golgi network. In its absence, secretory vesicle formation is impaired, leading to accumulation of immature vesicles, or lysosomal vesicle degradation.

scholarly journals Formation of secretory vesicles in permeabilized cells: a salt extract from yeast membranes promotes budding of nascent secretory vesicles from the trans-Golgi network of endocrine cells

1996 ◽  
Vol 314 (3) ◽  
pp. 723-726 ◽  
Author(s):  
Wai Lam W. LING ◽  
Dennis SHIELDS
Keyword(s):  
Mammalian Cells ◽  
Endocrine Cells ◽  
Secretory Vesicle ◽  
Gh3 Cells ◽  
Vesicle Formation ◽  
Secretory Vesicles ◽  
Vesicle Budding ◽  
Trans Golgi Network ◽  
Golgi Network ◽  
Salt Extract

The mechanism of secretory-vesicle formation from the trans-Golgi network (TGN) of endocrine cells is poorly understood. To identify cytosolic activities that facilitate the formation and fission of nascent secretory vesicles, we treated permeabilized pituitary GH3 cells with high salt to remove endogenous budding factors. Using this cell preparation, secretory-vesicle budding from the TGN required addition of exogenous cytosol and energy. Mammalian cytosols (GH3 cells and bovine brain) promoted post-TGN vesicle formation. Most significantly, a salt extract of membranes from the yeast Saccharomyces cerevisiae, a cell lacking a regulated secretory pathway, stimulated secretory vesicle budding in the absence of mammalian cytosolic factors. These results demonstrate that the factors which promote secretory-vesicle release from the TGN are conserved between yeast and mammalian cells.

scholarly journals Retromer revisited: Evolving roles for retromer in endosomal sorting

2017 ◽  
Vol 216 (11) ◽  
pp. 3433-3436 ◽  
Author(s):  
John P. Chamberland ◽  
Brigitte Ritter
Keyword(s):  
Mammalian Cells ◽  
Endosomal Sorting ◽  
Trans Golgi Network ◽  
Retromer Complex ◽  
Cell Biol ◽  
The Individual ◽  
Golgi Network

The highly conserved retromer complex has been linked to cargo retrieval from endosomes to the trans-Golgi network. In this issue, Kvainickas et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201702137) and Simonetti et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201703015) fundamentally question the current retromer model and demonstrate that in mammalian cells, the individual retromer subcomplexes have functionally diverged to organize multiple distinct sorting pathways.

GGA proteins: new players in the sorting game

2001 ◽  
Vol 114 (19) ◽  
pp. 3413-3418 ◽  
Author(s):  
Annette L. Boman
Keyword(s):  
Membrane Trafficking ◽  
Sequence Homology ◽  
Mammalian Cells ◽  
Gene Knockout ◽  
Protein Domains ◽  
Vesicle Formation ◽  
Trans Golgi Network ◽  
And Function ◽  
Golgi Network ◽  
Cargo Sorting

The GGA proteins are a novel family of proteins that were discovered nearly simultaneously by several labs studying very different aspects of membrane trafficking. Since then, several studies have described the GGA proteins and their functions in yeast and mammalian cells. Four protein domains are present in all GGA proteins, as defined by sequence homology and function. These different domains interact directly with ARF proteins, cargo and clathrin. Alteration of the levels of GGA proteins by gene knockout or overexpression affects specific trafficking events between the trans-Golgi network and endosomes. These data suggest that GGAs function as ARF-dependent, monomeric clathrin adaptors to facilitate cargo sorting and vesicle formation at the trans-Golgi network.

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