On the origin of lipid asymmetry: the flip side of ion transport.
Membrane lipid asymmetry influences a multitude of cellular functions, including membrane vesiculation, cell division, and lifespan. Most cells retain the bulk of aminophospholipids to the cytosolic membrane leaflet by means of ATP-fuelled flippases or translocases. Converging lines of evidence indicate that members of the P(4) subfamily of P-type ATPases catalyze aminophospholipid transport and create lipid asymmetry in late secretory and endocytic compartments. Yet P-type ATPases usually pump small cations or metal ions. Atomic structures revealed important aspects of the transport mechanism, and sequence homology indicates that this mechanism is conserved throughout the family. Consequently, understanding how P(4) ATPases acquired the ability to translocate phospholipids instead of simple ions has become a major focus of interest.
Lenoir
Guillaume
G
Department of Membrane Enzymology, Bijvoet Center and Institute of Biomembranes, Utrecht University, 3584 CH, Utrecht, The Netherlands.
Williamson
Patrick
P
Holthuis
Joost C  M
JC
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D017136:Ion Transport; D008958:Models, Molecular; D008969:Molecular Sequence Data; D049294:Phospholipid Transfer Proteins / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*
D049294:Phospholipid Transfer Proteins; D010743:Phospholipids; D000251:Adenosine Triphosphatases; D002118:Calcium