Trimeric G-proteins of the trans-Golgi network are involved in the formation of constitutive secretory vesicles and immature secretory granules.
Non-hydrolysable analogues of GTP, such as GTP gamma S and GMP-PNP, have previously been shown to inhibit the formation of constitutive secretory vesicles (CSVs) and immature secretory granules (ISGs) from the trans-Golgi network (TGN). Using a cell-free system, we show here that the formation of these vesicles is also inhibited by [A1F4]-, a compound known to act on trimeric G-proteins. Addition of highly purified G-protein beta gamma subunits stimulated, in a differential manner, the cell-free formation of both CSVs and ISGs. ADP-ribosylation experiments revealed the presence of a pertussis toxin-sensitive G-protein alpha subunit in the TGN. We conclude that trimeric G-proteins regulate the formation of secretory vesicles from the TGN.
Barr
F A
FA
Cell Biology Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
Leyte
A
A
Mollner
S
S
Pfeuffer
T
T
Tooze
S A
SA
Huttner
W B
WB
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000310:Adrenal Gland Neoplasms; D000535:Aluminum / Q000494:pharmacology; D017607:Aluminum Compounds; D002474:Cell-Free System; D003594:Cytoplasmic Granules / Q000502:physiology*; D005459:Fluorides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D006056:Golgi Apparatus / Q000737:chemistry* / Q000648:ultrastructure; D046911:Macromolecular Substances; D037342:Pertussis Toxin; D010673:Pheochromocytoma; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D017607:Aluminum Compounds; D046911:Macromolecular Substances; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D000535:Aluminum; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D005459:Fluorides; C032311:aluminum fluoride