Differential regulation of the lateral mobility of plasma membrane phospholipids by the extracellular matrix and cholesterol

✍ Scribed by O.G. Ramprasad; Nandini Rangaraj; G. Srinivas; Jean Paul Thiery; Sylvie Dufour; Gopal Pande

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 525 KB
• Volume: 215
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.21339

✦ Synopsis

Abstract

In this study, we compared qualitative and quantitative changes in the lateral mobility of phospholipid molecules in the plasma membrane of intact cells under various conditions of specific interaction of integrins in the cell membrane with two extracellular matrix (ECM) components viz. fibronectin (FN) and laminin (LN). We found a strong and specific correlation between the lower lateral mobility of phosphatidylcholine (PC) and higher lateral mobility of phosphatidylethanolamine (PE) when cells were expressing high levels of α5β1 integrin and thus were adherent and motile on FN. The interaction between PC and FN in α5 integrin expressing cells was aided by the strong affinity of α5 integrin to the FN matrix. Cholesterol was involved in regulating the lateral mobility of PC to a great extent and of PE to a lesser extent without affecting the overall microviscosity of the plasma membrane or the distribution of caveolin‐marked domains. The distribution and mobility of PC and PE molecules in the lamellipodial regions differed from that in the rest of the membrane and also in the more motile and in the less motile cells. We propose that these differences in distribution of PC and PE in different regions of cell membrane and their respective lateral mobility are observed due to the specific interaction of PC molecules with FN molecules in the ECM. Our results outline a new role of integrin–matrix interactions in the regulation of membrane phospholipid behavior. J. Cell. Physiol. 215: 550–561, 2008. © 2007 Wiley‐Liss, Inc.