PI4P/phosphatidylserine countertransport at ORP5- and ORP8-mediated ER–plasma membrane contacts

TLDR

Membrane contact sites facilitate lipid exchange, and distinct organelles and the plasma membrane possess unique phospholipid compositions, with a family of proteins crucial for maintaining cellular lipid balance. The proteins accumulate at ER–PM contact sites, tethering them and mediating phospholipid exchange to preserve the plasma membrane’s distinct identity. Chung et al.

Abstract

Membrane contact sites promote lipid exchange Most membrane lipids are manufactured in the endoplasmic reticulum (ER). Different organelles and the plasma membrane (PM) have distinct phospholipid compositions. Chung et al. , working in mammalian cells, and Moser von Filseck et al. , working in yeast, both describe how a family of proteins is important in maintaining the balance of lipids within the cell. These special proteins accumulate at and tether contact sites between the ER and the PM and promote the exchange of specific phospholipids, which helps to maintain the PM's distinct identity. Science , this issue pp. 428 and 432