Properties of membrane models containing glycolipids

• Grant number: 24/00974-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: July 01, 2024
• End date: April 30, 2026
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Karin Do Amaral Riske
• Grantee: Maria Clara Araujo Oliveira
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Biological membranes are essential for life, as they guarantee adequate protection, structuring and permeability to the cell, and are composed mainly of proteins and lipids, which form a lipid bilayer that provides their structural basis. The plasma membrane also has a rich glycocalyx, formed by glycated domains attached to proteins and lipids in its outer monolayer, which are responsible for all cellular signaling. Glycolipids make up the majority of the lipid portion in neuronal cells. However, the vast majority of studies with membrane model systems have been restricted to the study of glycerophospholipids and cholesterol, and little attention has been given to glycolipids. They are also found in membrane rafts, microdomains that form a liquid-ordered phase (Lo), with higher order than the rest of the membrane, in the liquid-disordered phase (Ld). Given the relevance of glycolipids in the metabolic and structural functions of the cell membrane, this Master's project aims to study the impact of three classes of glycolipids (cerebrosides, sulfatides and gangliosides) on the fluidity, packaging, Ld/Lo phase separation and stability of model membranes. To this end, we intend to obtain the gel-fluid phase transition profile of large unilamellar vesicles (LUVs) by differential scanning calorimetry (DSC), the membrane packing by measurements of fluorescence anisotropy as a function of temperature, the presence of separation of Ld/Lo phases by optical microscopy of giant unilamellar vesicles (GUVs) and line tension measurements from the dynamics of macropore closure induced by electrical pulses in GUVs. The lipid compositions studied will have up to 20 mol% glycolipids, located symmetrically and asymmetrically in the bilayer.