Fubito Nakatsu

Phosphatidylserine (PS) is a quantitively minor class of phospholipids that contributes to cellular membranes (1). PS is synthesized at the endoplasmic reticulum (ER) by PTDSS1 and PTDSS2, which replace the head-group of phosphatidylcholine (PC) or phosphatidylethanolamine (PE), respectively, with serine. Once synthesized, PS is transported primarily by a non-vesicular manner via membrane contact sites, where the ER is closely apposed to other cellular membranes (2).

Highlights • Loss of GPSN2 impairs brain development and neuronal polarization • Loss of GPSN2 induces severe reductions in VLCFA-containing ceramide and gangliosides • The growth cone after polarization is enriched in lipid rafts dependent on GPSN2 • Ceramide with VLCFAs rescues both lipid-raft distribution and neuronal polarity Summary Fatty acids have long been considered essential to brain development; however, the involvement of their synthesis in nervous system formation is unclear.