Thematic Review Series: Glycerolipids. Phosphatidylserine and phosphatidylethanolamine in mammalian cells: two metabolically related aminophospholipids

Abstract

Phosphatidylserine(PS)andphosphatidylethanolamine (PE) are two aminophospholipids whose metabolism is interrelated. Both phospholipids are components of mammalian cell membranes and play important roles in biological processes such as apoptosis and cell signaling. PS is synthesized in mammalian cells by base-exchange reactions in which polar head groups of preexisting phospholipids are replaced by serine. PS synthase activity resides primarily on mitochondria-associated membranes and is encoded by two distinct genes. Studies in mice in which each gene has been individually disrupted are beginning to elucidate the importance of these two synthases for biological functions in intact animals. PE is made in mammalian cells by two completely independent major pathways. In one pathway, PS is converted into PE by the mitochondrial enzyme PS decarboxylase. In addition, PE is made via the CDP-ethanolamine pathway, in which the final reaction occurs on the endoplasmic reticulum and nuclear envelope. The relative importance of these two pathways of PE synthesis has been investigated in knockout mice. Elimination of either pathway is embryonically lethal, despite the normal activity of the other pathway. PE can also be generated from a base-exchange reaction and by the acylation of lyso-PE. Cellular levels of PS and PE are tightly regulated by the implementation of multiple compensatory mechanisms.-Vance, J. E. Phosphatidylserine and phosphatidylethanolamine in mammalian cells: two metabolically related aminophospholipids.

ApoE4 upregulates the activity of mitochondria‐associated ER membranes

“…In particular, phosphatidylserine (PtdSer) is synthesized in MAM 26. PtdSer is then transported from the ER to mitochondria, where it is decarboxylated to produce phosphatidylethanolamine (PtdEtn); PtdEtn can then be transported back to the ER, where it is either methylated to produce phosphatidylcholine (PtdCho) or distributed to other membranes of the cell 27. Although some PtdEtn is produced on the cytosolic face of the ER by CDP‐ethanolamine exchange via the Kennedy pathway 28, the majority of PtdEtn is produced by the conversion of PtdSer to PtdEtn in mitochondria 25; this conversion is an established marker for ER–mitochondrial communication 25.…”

The follicular microenviroment as a predictor of pregnancy: MALDI-TOF MS lipid profile in cumulus cells

“…Finally, PI was identified in the non-pregnant group (m/z 807.4818) and is found relatively less often in the phospholipid cell membranes of mammals [42]. PI is a glycerophospholipid component in eukaryotic cells [36].…”

Tales and Mysteries of the Enigmatic Sphingomyelin Synthase Family

“…This second, insect-specific CPE synthase uses CDP-ethanolamine instead of PE as headgroup donor, 69 analogous to the ethanolaminephosphotransferases of the Kennedy pathway. 70 This implies that, contrary to SM synthesis in mammals, bulk production of CPE in insects occurs in the cytosolic leaflet of the membrane. As insects require CERT for efficient CPE production, 68 the CDP-ethanolamine-dependent CPE synthase likely resides in the Golgi apparatus.…”