THE LIPID TRANSPORT PROTEIN STARD7 LEVELS MODIFIES MITOCHONDRIAL DYNAMICS

MAR DEL PLATA

Congreso; LXIII Reunión anual de la sociedad Argentina de Investigación en Clínica (SAIC); 2018

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA

Mitochondria are dynamics organelles crucial for cell function and survival implicated in oxidative energy production. Mitochondrial lipids affect several important functions such as respiratory metabolism, membrane architecture, protein import, mitophagy and mitochondrial dynamics. StarD7 is a lipid transport protein that carries phosphatidylcholine (PC) to the mitochondria. Previous studies have shown that StarD7 knockdown induces alterations in mitochondria and endoplasmic reticulum morphology with a reduction in mitochondrial PC content, however how different StarD7 levels affects the mitochondrial dynamics was unexplored. Here, we generated a HTR8/SVneo stable cell line expressing the StarD7-I isoform (StarD7-I) that has a mitochondrial targeting signal. We demonstrated that StarD7 overexpression promotes altered mitochondrial morphology with greater mitochondria motility. Mitochondrial targeting photoactivable (PA-GFP) protein assays indicated that mitochondria from StarD7-I-overexpressing cells were able to produce transient fusions. StarD7-I cells maintain the mitochondrial membrane potential and generate lower ROS levels than control cells. Additionally, an increase in the expression of Drp-1 fission protein was detected in StarD7-I cells. Based on these data, we concluded that StarD7-I overexpression leads to transient mitochondria fusion events without affecting the mitochondrial membrane potential.