G protein-membrane interactions II: Effect of G Protein-linked Lipids on Membrane Structure and G Protein-membrane Interactions
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Date
2017-07-03Author
Casas, Jesús
Álvarez, Rafael
Terés, Silvia
LLadó, Victoria
Piotto, Stefano
Concilio, Simona
Escriba, Pablo V.
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Biochimica et Biophysica Acta - Biomembranes 1859(9) : 1526-1535 (2017)
Abstract
[EN] G proteins often bear myristoyl, palmitoyl and isoprenyl moieties, which favor their
association with the membrane and their accumulation in G Protein Coupled Receptor-rich
microdomains. These lipids influence the biophysical properties of membranes and thereby
modulate G protein binding to bilayers. In this context, we showed here that geranylgeraniol, but
neither myristate nor palmitate, increased the inverted hexagonal (HII) phase propensity of
phosphatidylethanolamine-containing membranes. While myristate and palmitate preferentially
associated with phosphatidylcholine membranes, geranylgeraniol favored nonlamellar-prone
membranes. In addition, Gi1 monomers had a higher affinity for lamellar phases, while G and
G showed a marked preference for nonlamellar prone membranes. Moreover, geranylgeraniol
enhanced the binding of G protein dimers and trimers to phosphatidylethanolamine-containing
membranes, yet it decreased that of monomers. By contrast, both myristate and palmitate
increased the Gi1 preference for lamellar membranes. Palmitoylation reinforced the binding of
the monomer to PC membranes and myristoylation decreased its binding to PE-enriched bilayer.
Finally, binding of dimers and trimers to lamellar-prone membranes was decreased by palmitate
and myristate, but it was increased in nonlamellar-prone bilayers. These results demonstrate that
co/post-translational G protein lipid modifications regulate the membrane lipid structure and that
they influence the physico-chemical properties of membranes, which in part explains why G
protein subunits sort to different plasma membrane domains.