Distribution of phosphatidylethanolamine in intracellular membrane networks

Abstract

Phosphatidylethanolamine (PE) is a ubiquitous phospholipid in mammalian cellular membranes. We characterized PE distribution in intracellular membrane networks using exogenously delivered GFP‐tagged duramycin probes. The trans‐Golgi was the most prominently stained organelle. Positive staining was observed at the cytosolic side of the ER, cis‐Golgi, endosomes and autophagosomes, but not the mitochondria. The nuclear membrane was strongly stained from the luminal but not the cytosolic side. A distinct, granulated staining pattern was identified at the luminal surfaces of early endosomes. Dual staining for PE and phosphatidylserine (PS) revealed drastically different patterns, consistent with fundamentally distinct roles for these phospholipids in the intracellular membrane networks. The plasma membrane inner surface was negative for either probe. Overall, the data provided information on the intracellular distribution of PE, in comparison to that of PS; and were implicative of differential regulatory mechanisms for these synthetically linked but structurally and functionally distinct aminophospholipids.