Lipid-protein interactions in mitochondrial membranes from bivalve mollusks: molecular strategies in different species

Abstract

The mitochondrial FF-ATPase, the key enzyme in cell bioenergetics, apparently works in the same way in mollusks and in mammals. We previously pointed out a raft-like arrangement in mussel gill mitochondrial membranes, which apparently distinguishes bivalve mollusks from mammals. To explore the relationship between the microenvironmental features and the enzyme activity, the physico-chemical features of mitochondrial membranes and the FF-ATPase activity temperature-dependence are here explored in the Manila clam (Ruditapes philippinarum). Similarly to the mussel, clam gill mitochondrial membrane lipids exhibit a high sterol content (42 mg/g protein), mainly due to phytosterols (cholesterol only attains 42% of total sterols), and abundant polyunsaturated fatty acids (PUFA) (70% of total fatty acids), especially of the n-3 family. However, the FF-ATPase activation energies above and below the break in the Arrhenius plot (22.1 °C) are lower than in mussel and mammalian mitochondria. Laurdan fluorescence spectroscopy analyses carried out at 10 °C, 20 °C and 30 °C on mitochondrial membranes and on lipid vesicles obtained from total lipid extracts of mitochondria, indicate a physical state without coexisting domains. This mitochondrial membrane constitution, allowed by lipid-lipid and lipidprotein interactions and involving PUFA-rich phospholipids, phytosterols (much more diversified in clams than in mussels) and proteins, enables the maintenance of a homogeneous physical state in the range 10-30 °C. Consistently, this molecular interaction network would somehow extend the temperature range of the FF-ATPase activity and may contribute to clam resilience to temperature changes.

Cholesterol‐containing lipid nanodiscs promote an α‐synuclein binding mode that accelerates oligomerization

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Kingdom-specific lipid unsaturation shapes up sequence evolution in membrane arm subunits of eukaryotic respiratory complexes

“…PUFA is also prevalent in aqueous metazoans to maintain membrane fluidity 88 . Accordingly, investigating evolution of lipid unsaturation in non-mitochondrial membranes and correlated sequence divergence in membrane-embedded proteins would be interesting.…”

Investigating the Mechanism of Low-Salinity Environmental Adaptation in Sepia esculenta Larvae through Transcriptome Profiling

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