title: The physics of lipid droplet nucleation, growth and budding.
abstract: Lipid droplets (LDs) are intracellular oil-in-water emulsion droplets, covered by a phospholipid monolayer and mainly present in the cytosol. Despite their important role in cellular metabolism and growing number of newly identified functions, LD formation mechanism from the endoplasmic reticulum remains poorly understood. To form a LD, the oil molecules synthesized in the ER accumulate between the monolayer leaflets and induce deformation of the membrane. This formation process works through three steps: nucleation, growth and budding, exactly as in phase separation and dewetting phenomena. These steps involve sequential biophysical membrane remodeling mechanisms for which we present basic tools of statistical physics, membrane biophysics, and soft matter science underlying them. We aim to highlight relevant factors that could control LD formation size, site and number through this physics description. An emphasis will be given to a currently underestimated contribution of the molecular interactions between lipids to favor an energetically costless mechanism of LD formation.
authors.affiliation: Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Universités UPMC Univ Paris 06, CNRS, 24 rue Lhomond, 75005 Paris, France. Electronic address: thiam@lps.ens.fr.
authors.forename: Abdou Rachid
authors.initials: AR
authors.lastname: Thiam
authors.affiliation: Laboratoire de Physique Statistique, École Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris-Cité, Sorbonne Universités UPMC Univ Paris 06, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Forêt
mesh_terms: D000818:Animals; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D066292:Lipid Droplets / Q000737:chemistry* / Q000378:metabolism; D008956:Models, Chemical; D009821:Oils / Q000737:chemistry* / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000737:chemistry* / Q000378:metabolism
chemical_list: D009821:Oils; D010743:Phospholipids; D014867:Water
keywords: Biophysics; Budding; Emulsions; Lipid droplets; Membrane; Metabolism