Cellular fate of phospholipids (PL) synthesized during G2/M

LUCIANA RODRIGUEZ SAWICKI; VERONICA VICTORIA MOSCOSO; ANA VES-LOSADA; BETINA CÓRSICO; NATALIA SCAGLIA

Congreso; LII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2016

Cell division ends upwith the reassemble of the nuclear envelope and the separation of two daughtercells, process that requires dynamic changes in the distribution andcomposition of membrane PL. We have previously found that lysoPL levelsdecrease drastically from G2/M to G1 phase, while de novo phosphatidylcholine(PC) synthesis increases, suggesting an enhanced membrane productionconcomitant with a decrease in its turnover. In addition, fatty acid (FA) synthesisand incorporation into membranes increases upon cell division (Scaglia, 2014). Thus,our aim is to study the cellular fate of synthesized PL during G2/M.We synchronized HeLacells to study lipid synthesis during G2/M. Metabolic labeling with 14C-acetate and the subsequentseparation of subcellular fractions with a sucrose gradient allowed us todetermine the distribution of incorporated label into lipids during celldivision. We also used the choline analog propargylcholine (p-Cho) to assessthe fate of newly synthesized PL in G2/M. The resulting propargyl-labeled PLmolecules were visualized via a click chemistry reaction with an azide-Alexa488(Jao, 2009). Both techniques, incorporation of 14C-acetate and p-Cholabeling, showed that lipids synthesized during G2/M localized in a regioncompatible with the nucleus and endoplasmic reticulum.  These studies will contribute to the knowledgeof the metabolic requirements during the cell cycle and could have implicationsfor the treatment and diagnosis of hyperproliferative diseases.