Early stages of Golgi vesicle and tubule formation require diacylglycerol.
We have investigated the role for diacylglycerol (DAG) in membrane bud formation in the Golgi apparatus. Addition of propranolol to specifically inhibit phosphatidate phosphohydrolase (PAP), an enzyme responsible for converting phosphatidic acid into DAG, effectively prevents formation of membrane buds. The effect of PAP inhibition on Golgi membranes is rapid and occurs within 3 min. Removal of the PAP inhibitor then results in a rapid burst of buds, vesicles, and tubules that peaks within 2 min. The inability to form buds in the presence of propranolol does not appear to be correlated with a loss of ARFGAP1 from Golgi membranes, as knockdown of ARFGAP1 by RNA interference has little or no effect on actual bud formation. Rather, knockdown of ARFGAP1 results in an increase in membrane buds and a decrease of vesicles and tubules suggesting it functions in the late stages of scission. How DAG promotes bud formation is discussed.
Asp
Lennart
L
Department of Medical and Clinical Genetics, the Sahlgrenska Academy at the University of Gothenburg, 405 30 Gothenburg, Sweden.
Kartberg
Fredrik
F
Fernandez-Rodriguez
Julia
J
Smedh
Maria
M
Elsner
Markus
M
Laporte
Frederic
F
Bárcena
Montserrat
M
Jansen
Karen A
KA
Valentijn
Jack A
JA
Koster
Abraham J
AJ
Bergeron
John J M
JJ
Nilsson
Tommy
T
D000818:Animals; D004075:Diglycerides / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000378:metabolism; D006056:Golgi Apparatus / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008954:Models, Biological; D010711:Phosphatidate Phosphatase / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism; D051381:Rats
C011439:1,2-diacylglycerol; C503237:ARFGAP1 protein, human; D004075:Diglycerides; D020690:GTPase-Activating Proteins; D010712:Phosphatidic Acids; D010711:Phosphatidate Phosphatase