TitleCDS2 expression regulates de novo phosphatidic acid synthesis.
Publication TypeJournal Article
Year of Publication2024
AuthorsCollins DM, Janardan V, Barneda D, Anderson KE, Niewczas I, Taylor D, Qiu D, Jessen HJ, Lopez-Clavijo AF, Walker S, Raghu P, Clark J, Stephens LR, Hawkins PT
JournalBiochem J
Volume481
Issue20
Pagination1449-1473
Date Published2024 Oct 16
ISSN1470-8728
KeywordsAnimals, Calcium, Diacylglycerol Cholinephosphotransferase, Macrophages, Mice, Mice, Inbred C57BL, Mice, Knockout, Phosphatidic Acids
Abstract

CDS enzymes (CDS1 and 2 in mammals) convert phosphatidic acid (PA) to CDP-DG, an essential intermediate in the de novo synthesis of PI. Genetic deletion of CDS2 in primary mouse macrophages resulted in only modest changes in the steady-state levels of major phospholipid species, including PI, but substantial increases in several species of PA, CDP-DG, DG and TG. Stable isotope labelling experiments employing both 13C6- and 13C6D7-glucose revealed loss of CDS2 resulted in a minimal reduction in the rate of de novo PI synthesis but a substantial increase in the rate of de novo PA synthesis from G3P, derived from DHAP via glycolysis. This increased synthesis of PA provides a potential explanation for normal basal PI synthesis in the face of reduced CDS capacity (via increased provision of substrate to CDS1) and increased synthesis of DG and TG (via increased provision of substrate to LIPINs). However, under conditions of sustained GPCR-stimulation of PLC, CDS2-deficient macrophages were unable to maintain enhanced rates of PI synthesis via the 'PI cycle', leading to a substantial loss of PI. CDS2-deficient macrophages also exhibited significant defects in calcium homeostasis which were unrelated to the activation of PLC and thus probably an indirect effect of increased basal PA. These experiments reveal that an important homeostatic response in mammalian cells to a reduction in CDS capacity is increased de novo synthesis of PA, likely related to maintaining normal levels of PI, and provides a new interpretation of previous work describing pleiotropic effects of CDS2 deletion on lipid metabolism/signalling.

DOI10.1042/BCJ20240456
Alternate JournalBiochem J
PubMed ID39312194