Membrane potential governs lateral segregation of plasma membrane proteins and lipids in yeast.

Sorting of plasma membrane proteins into exocytic vesicles at the yeast trans-Golgi network (TGN) is believed to be mediated by their coalescence with specific lipids, but how these membrane-remodeling events are regulated is poorly understood. Here we show that the ATP-dependent phospholipid flippase Drs2 is required for efficient segregation of cargo into exocytic vesicles. The plasma membrane proteins Pma1 and Can1 are missorted from the TGN to the vacuole in drs2∆ cells. We also used a combination of flippase mutants that either gain or lose the ability to flip phosphatidylserine (PS) to determine that PS flip by Drs2 is its critical function in this sorting event. The primary role of PS flip at the TGN appears to be to control the oxysterol-binding protein homologue Kes1/Osh4 and regulate ergosterol subcellular distribution. Deletion of KES1 suppresses plasma membrane–missorting defects and the accumulation of intracellular ergosterol in drs2 mutants. We propose that PS flip is part of a homeostatic mechanism that controls sterol loading and lateral segregation of protein and lipid domains at the TGN.

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Detergent fractionation with subsequent subtractive suppression hybridization as a tool for identifying genes coding for plasma membrane proteins

Experimental Dermatology ◽

10.1111/j.1600-0625.2008.00821.x ◽

2009 ◽

Vol 18 (6) ◽

pp. 527-535 ◽

Cited By ~ 2

Author(s):

Andreas Lange ◽

Claudia Kistler ◽

Tanja B. Jutzi ◽

Alexandr V. Bazhin ◽

Claus Detlev Klemke ◽

...

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Plasma Membrane Proteins ◽

Subtractive Suppression Hybridization

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Evidence That Type I, II, and III Inositol 1,4,5-Trisphosphate Receptors Can Occur as Integral Plasma Membrane Proteins

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)61534-6 ◽

2000 ◽

Vol 275 (35) ◽

pp. 27488-27493

Author(s):

Akihiko Tanimura ◽

Yosuke Tojyo ◽

R. James Turner

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Type I ◽

Plasma Membrane Proteins ◽

Inositol 1,4,5 Trisphosphate

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pH-dependent Cargo Sorting from the Golgi

Journal of Biological Chemistry ◽

10.1074/jbc.m110.197889 ◽

2011 ◽

Vol 286 (12) ◽

pp. 10058-10065 ◽

Cited By ~ 34

Author(s):

Chunjuan Huang ◽

Amy Chang

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Atpase Activity ◽

Secretory Pathway ◽

Ph Dependence ◽

Glucose Deprivation ◽

Ph Homeostasis ◽

Plasma Membrane Proteins ◽

Cytosolic Ph ◽

Cargo Sorting

The vacuolar proton-translocating ATPase (V-ATPase) plays a major role in organelle acidification and works together with other ion transporters to maintain pH homeostasis in eukaryotic cells. We analyzed a requirement for V-ATPase activity in protein trafficking in the yeast secretory pathway. Deficiency of V-ATPase activity caused by subunit deletion or glucose deprivation results in missorting of newly synthesized plasma membrane proteins Pma1 and Can1 directly from the Golgi to the vacuole. Vacuolar mislocalization of Pma1 is dependent on Gga adaptors although no Pma1 ubiquitination was detected. Proper cell surface targeting of Pma1 was rescued in V-ATPase-deficient cells by increasing the pH of the medium, suggesting that missorting is the result of aberrant cytosolic pH. In addition to mislocalization of the plasma membrane proteins, Golgi membrane proteins Kex2 and Vrg4 are also missorted to the vacuole upon loss of V-ATPase activity. Because the missorted cargos have distinct trafficking routes, we suggest a pH dependence for multiple cargo sorting events at the Golgi.

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