The lysophospholipid acyltransferase antagonist CI-976 inhibits a late step in COPII vesicle budding.
The mechanism of coat protein (COP)II vesicle fission from the endoplasmic reticulum (ER) remains unclear. Lysophospholipid acyltransferases (LPATs) catalyze the conversion of various lysophospholipids to phospholipids, a process that can promote spontaneous changes in membrane curvature. Here, we show that 2,2-methyl-N-(2,4,6,-trimethoxyphenyl)dodecanamide (CI-976), a potent LPAT inhibitor, reversibly inhibited export from the ER in vivo and the formation of COPII vesicles in vitro. Moreover, CI-976 caused the rapid and reversible accumulation of cargo at ER exit sites (ERESs) containing the COPII coat components Sec23/24 and Sec13/31 and a marked enhancement of Sar1p-mediated tubule formation from ERESs, suggesting that CI-976 inhibits the fission of assembled COPII budding elements. These results identify a small molecule inhibitor of a very late step in COPII vesicle formation, consistent with fission inhibition, and demonstrate that this step is likely facilitated by an ER-associated LPAT.
Brown
William J
WJ
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA. wjb5@cornell.edu
Plutner
Helen
H
Drecktrah
Daniel
D
Judson
Bret L
BL
Balch
William E
WE
D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000813:Anilides / Q000378:metabolism*; D000818:Animals; D022181:COP-Coated Vesicles / Q000378:metabolism*; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000378:metabolism
D000813:Anilides; D004791:Enzyme Inhibitors; C028391:G protein, vesicular stomatitis virus; D008562:Membrane Glycoproteins; D033921:Vesicular Transport Proteins; D014759:Viral Envelope Proteins; C069304:PD 128042; D006160:Guanosine Triphosphate; D008243:1-Acylglycerophosphocholine O-Acyltransferase; C487879:SAR1 protein, rat; D020559:Monomeric GTP-Binding Proteins