An electrostatic switching mechanism to control the lipid transfer activity of Osh6p

Lipp, Nicolas-Frédéric; Gautier, Romain; Magdeleine, Maud; Renard, Maxime; Albanèse, Véronique; Čopič, Alenka; Drin, Guillaume

doi:10.1038/s41467-019-11780-y

Cited by 36 publications

(49 citation statements)

References 75 publications

(123 reference statements)

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“…In this regard, we reported an apparent affinity of SWG for the ORD in the presence of detergent micelles of Kd~35 nM, which is rather low compared to the measured Ki. Akin to what has been observed recently on Osh6 (29), the ORD lid is probably unlocked by the interfacial micellar environment, hence leading to faster exchange kinetics and lower affinities. Further studies of the kinetics of SWG binding to or dissociation from the ORD with liposomes of defined composition should give information on the interfacial interactions involved in lipid exchange.…”

Section: Discussionsupporting

confidence: 59%

Molecular and cellular dissection of the OSBP cycle through a fluorescent inhibitor

eacuteresse

Kovács

Subra

et al. 2019

Preprint

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ORPphilins, natural molecules that strongly and selectively inhibit the growth of some cancer cell lines, are proposed to target intracellular lipidtransfer proteins of the Oxysterol-binding protein (OSBP) family. These conserved proteins exchange key lipids, such as cholesterol and phopsphatidylinositol-4-phosphate (PI(4)P), between organelle membranes. Among ORPphilins, molecules of the schweinfurthin family interfere with intracellular lipid distribution and metabolism, but their functioning at the molecular level is poorly understood. We report here that cell line sensitivity to schweinfurthin G (SWG) is inversely proportional to cellular level of OSBP. By taking advantage of the intrinsic fluorescence of SWG, we follow its fate in cell cultures and show that its incorporation at the TGN depends on OSBP cellular abundance. We report that SWG inhibits specifically the lipid exchange cycle of OSBP. As a consequence, post-Golgi trafficking, membrane cholesterol levels and PI(4)P turnover are affected. Finally, we demonstrate the direct binding of SWG into OSBP lipid-binding cavity by intermolecular FRET. Collectively these data describe for the first time a specific and intrinsically fluorescent pharmacological tool to dissect OSBP properties at the cellular and molecular levels. _______________________________________

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Section: Discussionsupporting

confidence: 59%

Molecular and cellular dissection of the OSBP cycle through a fluorescent inhibitor

eacuteresse

Kovács

Subra

et al. 2019

Preprint

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“…In contrast, Osh6 consists only of an ORD and how it targets the ER and the PM is not known. We have previously demonstrated that to some extent, the cellular localization of Osh6 is regulated by its intrinsic avidity for lipid membranes (Lipp et al, 2019). However, this does not explain how Osh6 specifically targets its donor and acceptor compartments and how it maintains accuracy in PS transport.…”

Section: Introductionmentioning

confidence: 95%

Osh6 requires Ist2 for localization to ER–PM contacts and efficient phosphatidylserine transport in budding yeast

D’Ambrosio

Albanèse

Lipp

et al. 2020

Journal of Cell Science

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Osh6 and Osh7 are lipid transfer proteins (LTPs) that move phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS level at the PM is key for many cellular functions. Intriguingly, Osh6/7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homologue of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6Δ osh7Δ deletion: they decrease cellular PS levels, and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.

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“…We therefore wanted to map the Ist2-interaction site on Osh6. Previous work revealed key residues (H157/H158 and L69) that coordinate the lipid ligand inside the binding pocket, and the importance of the N-ter region (1-69), which forms a lid over the binding pocket and regulates Osh6 interaction with lipid membranes (Maeda et al, 2013;Lipp et al, 2019). Mutation or deletion of these residues did not affect Osh6-Ist2 interaction ( Fig.…”

Section: Mapping the Ist2 Interaction Site On Osh6mentioning

confidence: 86%

Osh6 requires Ist2 for localization to the ER-PM contacts and efficient phosphatidylserine transport

D’Ambrosio

Albanèse

Lipp

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Osh6 and Osh7 are lipid transfer proteins (LTPs) that transport phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS level at the PM is key for many cellular functions. Intriguingly, Osh6/7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homologue of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6D osh7D deletion: they decrease cellular PS levels, and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.

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An electrostatic switching mechanism to control the lipid transfer activity of Osh6p

Cited by 36 publications

References 75 publications

Molecular and cellular dissection of the OSBP cycle through a fluorescent inhibitor

Molecular and cellular dissection of the OSBP cycle through a fluorescent inhibitor

Osh6 requires Ist2 for localization to ER–PM contacts and efficient phosphatidylserine transport in budding yeast

Osh6 requires Ist2 for localization to the ER-PM contacts and efficient phosphatidylserine transport

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