Effects of phosphatidylethanolamine glycation on lipid-protein interactions and membrane protein thermal stability.
Non-enzymatic glycation of biomolecules has been implicated in the pathophysiology of aging and diabetes. Among the potential targets for glycation are biological membranes, characterized by a complex organization of lipids and proteins interacting and forming domains of different size and stability. In the present study, we analyse the effects of glycation on the interactions between membrane proteins and lipids. The phospholipid affinity for the transmembrane surface of the PMCA (plasma-membrane Ca(2+)-ATPase) was determined after incubating the protein or the phospholipids with glucose. Results show that the affinity between PMCA and the surrounding phospholipids decreases significantly after phosphospholipid glycation, but remains unmodified after glycation of the protein. Furthermore, phosphatidylethanolamine glycation decreases by approximately 30% the stability of PMCA against thermal denaturation, suggesting that glycated aminophospholipids induce a structural rearrangement in the protein that makes it more sensitive to thermal unfolding. We also verified that lipid glycation decreases the affinity of lipids for two other membrane proteins, suggesting that this effect might be common to membrane proteins. Extending these results to the in vivo situation, we can hypothesize that, under hyperglycaemic conditions, glycation of membrane lipids may cause a significant change in the structure and stability of membrane proteins, which may affect the normal functioning of membranes and therefore of cells.
Departamentos de Física y Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria-1428 Buenos Aires, Argentina.
Valeria
V
Levi
Ana M
AM
Villamil Giraldo
Pablo R
PR
Castello
Juan P F C
JP
Rossi
F Luis
FL
González Flecha
D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry; D003902:Detergents / Q000737:chemistry; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004795:Enzyme Stability; D004912:Erythrocytes / Q000201:enzymology; D005947:Glucose / Q000737:chemistry; D017127:Glycation End Products, Advanced / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D008823:Micelles; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000097:blood / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011489:Protein Denaturation / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry; D013552:Swine
D001457:Anion Exchange Protein 1, Erythrocyte; D003902:Detergents; D017127:Glycation End Products, Advanced; D008565:Membrane Proteins; D008823:Micelles; D010714:Phosphatidylethanolamines; C478747:polyoxyethylene-10-dodecyl ether; C483858:phosphatidylethanolamine; D011092:Polyethylene Glycols; D053499:Plasma Membrane Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D005947:Glucose; D004134:Dimyristoylphosphatidylcholine; C018525:1,2-dimyristoylphosphatidylethanolamine