A phosphatidylinositol transfer protein controls the phosphatidylcholine content of yeast Golgi membranes.
SEC14p is required for protein transport from the yeast Golgi complex. We describe a quantitative analysis of yeast bulk membrane and Golgi membrane phospholipid composition under conditions where Golgi secretory function has been uncoupled from its usual SEC14p requirement. The data demonstrate that SEC14p specifically functions to maintain a reduced phosphatidylcholine content in Golgi membranes and indicate that overproduction of SEC14p markedly reduces the apparent rate of phosphatidylcholine biosynthesis via the CDP-choline pathway in vivo. We suggest that SEC14p serves as a sensor of Golgi membrane phospholipid composition through which the activity of the CDP-choline pathway in Golgi membranes is regulated such that a phosphatidylcholine content that is compatible with the essential secretory function of these membranes is maintained.
McGee
T P
TP
Department of Cell Biology, University of Alabama at Birmingham 35294-0005.
Skinner
H B
HB
Whitters
E A
EA
Henry
S A
SA
Bankaitis
V A
VA
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003566:Cytidine Diphosphate Choline / Q000378:metabolism; D006056:Golgi Apparatus / Q000737:chemistry / Q000378:metabolism*; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins; D008954:Models, Biological; D009154:Mutation; D010713:Phosphatidylcholines / Q000032:analysis / Q000096:biosynthesis*; D010716:Phosphatidylinositols / Q000378:metabolism*; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids / Q000032:analysis; D029701:Saccharomyces cerevisiae Proteins; D015003:Yeasts
D002352:Carrier Proteins; D008565:Membrane Proteins; D010713:Phosphatidylcholines; D010716:Phosphatidylinositols; D049294:Phospholipid Transfer Proteins; D010743:Phospholipids; C118289:SEC24 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D003566:Cytidine Diphosphate Choline