In animal cells, the plasma membrane (PM) exhibits an asymmetrical distribution of phospholipids. Phosphatidylserine (PS) and phosphatidylethanolamine (PE) are found exclusively in the cytoplasmic leaflet, while phosphatidylcholine (PC) and sphingomyelin (SM) are predominantly concentrated in the extracellular leaflet. Although PC and SM are the most abundant phospholipids in the PM and have documented roles in human diseases, the mechanisms regulating their distribution remain unclear.

The research group led by Katsumori Segawa (Institute of Science Tokyo) and Shigekazu Nagata (Biochemistry & Immunology, WPI-IFReC) found that TMEM63B functions as a lipid scramblase at the PM and at lysosomal membranes, mediating bidirectional scrambling of various phospholipids in response to changes in membrane structure, such as membrane thickness (induced by cholesterol depletion) and membrane curvature (induced by phospholipase treatment).
(online publishing in Nat Struct Mol Biol. on Oct. 18, 2024)

Contact

Prof. Shigekazu Nagata

snagataifrec.osaka-u.ac.jp

Biochemistry & Immunology