Lipid species affect morphology of endoplasmic reticulum: a sea urchin oocyte model of reversible manipulation

Autor: Gabriela Ulloa, Fadi Hamati, Alexander Dick, Julie Fitzgerald, Judith Mantell, Paul Verkade, Lucy Collinson, Kenton Arkill, Banafshe Larijani, Dominic Poccia
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Journal of Lipid Research, Vol 60, Iss 11, Pp 1880-1891 (2019)
Druh dokumentu: article
ISSN: 0022-2275
DOI: 10.1194/jlr.RA119000210
Popis: The ER is a large multifunctional organelle of eukaryotic cells. Malfunction of the ER in various disease states, such as atherosclerosis, diabetes, cancer, Alzheimer's and Parkinson's and amyotrophic lateral sclerosis, often correlates with alterations in its morphology. The ER exhibits regionally variable membrane morphology that includes, at the extremes, large relatively flat surfaces and interconnected tubular structures highly curved in cross-section. ER morphology is controlled by shaping proteins that associate with membrane lipids. To investigate the role of these lipids, we developed a sea urchin oocyte model, a relatively quiescent cell in which the ER consists mostly of tubules. We altered levels of endogenous diacylglycerol (DAG), phosphatidylethanolamine (PtdEth), and phosphatidylcholine by microinjection of enzymes or lipid delivery by liposomes and evaluated shape changes with 2D and 3D confocal imaging and 3D electron microscopy. Decreases and increases in the levels of lipids such as DAG or PtdEth characterized by negative spontaneous curvature correlated with conversion to sheet structures or tubules, respectively. The effects of endogenous alterations of DAG were reversible upon exogenous delivery of lipids of negative spontaneous curvature. These data suggest that proteins require threshold amounts of such lipids and that localized deficiencies of the lipids could contribute to alterations of ER morphology. The oocyte modeling system should be beneficial to studies directed at understanding requirements of lipid species in interactions leading to alterations of organelle shaping.
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