Membrane Lipid Requirements of the Lysine Transporter Lyp1 from Saccharomyces cerevisiae.
J Mol Biol
; 432(14): 4023-4031, 2020 06 26.
Article
em En
| MEDLINE
| ID: mdl-32413406
ABSTRACT
Membrane lipids act as solvents and functional cofactors for integral membrane proteins. The yeast plasma membrane is unusual in that it may have a high lipid order, which coincides with low passive permeability for small molecules and a slow lateral diffusion of proteins. Yet, membrane proteins whose functions require altered conformation must have flexibility within membranes. We have determined the molecular composition of yeast plasma membrane lipids located within a defined diameter of model proteins, including the APC-superfamily lysine transporter Lyp1. We now use the composition of lipids that naturally surround Lyp1 to guide testing of lipids that support the normal functioning of the transporter, when reconstituted in vesicles of defined lipid composition. We find that phosphatidylserine and ergosterol are essential for Lyp1 function, and the transport activity displays a sigmoidal relationship with the concentration of these lipids. Non-bilayer lipids stimulate transport activity, but different types are interchangeable. Remarkably, Lyp1 requires a relatively high fraction of lipids with one or more unsaturated acyl chains. The transport data and predictions of the periprotein lipidome of Lyp1 support a new model in which a narrow band of lipids immediately surrounding the transmembrane stalk of a model protein allows conformational changes in the protein.
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MEDLINE
Assunto principal:
Proteínas de Membrana Transportadoras
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Saccharomyces cerevisiae
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Sistemas de Transporte de Aminoácidos Básicos
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Proteínas de Saccharomyces cerevisiae
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Lipídeos de Membrana
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article