Editing Lipid (section)

===Signaling===
Evidence has emerged showing that [[lipid signaling]] is a vital part of the [[cell signaling]].<ref name="pmid21743455">{{cite journal | vauthors = Malinauskas T, Aricescu AR, Lu W, Siebold C, Jones EY | title = Modular mechanism of Wnt signaling inhibition by Wnt inhibitory factor 1 | journal = Nature Structural & Molecular Biology | volume = 18 | issue = 8 | pages = 886–893 | date = July 2011 | pmid = 21743455 | pmc = 3430870 | doi = 10.1038/nsmb.2081 }}</ref><ref name="pmid=18256869">{{cite journal | vauthors = Malinauskas T | title = Docking of fatty acids into the WIF domain of the human Wnt inhibitory factor-1 | journal = Lipids | volume = 43 | issue = 3 | pages = 227–230 | date = March 2008 | pmid = 18256869 | doi = 10.1007/s11745-007-3144-3 | s2cid = 31357937 }}</ref><ref name="Wang_2004"/><ref name="Dinasarapu_2011"/> Lipid signaling may occur via activation of [[G protein-coupled receptor|G protein-coupled]] or [[nuclear receptor]]s, and members of several different lipid categories have been identified as signaling molecules and [[Second messenger system|cellular messengers]].<ref name="Eyster_2007"/> These include [[sphingosine-1-phosphate]], a sphingolipid derived from ceramide that is a potent messenger molecule involved in regulating calcium mobilization,<ref name="Hinkovska-Galcheva_2008"/> cell growth, and apoptosis;<ref name="Saddoughi_2008"/> [[diacylglycerol]] and the [[phosphatidylinositol]] phosphates (PIPs), involved in calcium-mediated activation of [[protein kinase C]];<ref name="Klein_2008"/> the [[prostaglandins]], which are one type of fatty-acid derived eicosanoid involved in [[inflammation]] and [[immunity (medical)|immunity]];<ref name="Boyce_2008"/> the steroid hormones such as [[estrogen]], [[testosterone]] and [[cortisol]], which modulate a host of functions such as reproduction, metabolism and blood pressure; and the [[oxysterol]]s such as 25-hydroxy-cholesterol that are [[liver X receptor]] [[agonist]]s.<ref name="Bełtowski 2008"/> Phosphatidylserine lipids are known to be involved in signaling for the phagocytosis of apoptotic cells or pieces of cells. They accomplish this by being exposed to the extracellular face of the cell membrane after the inactivation of [[flippase]]s which place them exclusively on the cytosolic side and the activation of scramblases, which scramble the orientation of the phospholipids. After this occurs, other cells recognize the phosphatidylserines and phagocytosize the cells or cell fragments exposing them.<ref name="Biermann 2013"/>