Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast

Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D.; Andersen, Tonni Grube; Pomorski, Thomas

doi:10.1111/1567-1364.12219

Cited by 16 publications

(20 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the yeast Candida albicans , a subfamily member (Cdr3p) has been identified that exhibits an inward-directed phospholipid translocase activity. Some yeast ABC transporters (Aus1p and Pdr11p in S. cerevisiae; Aus1p in Candida glabrata ) facilitate exogenous sterol uptake [143–148]. Three Arabidopsis proteins, TGD1-3, are proposed to form an ABC transporter complex in the inner envelope of the chloroplast that imports PA into the inside of the chloroplast for the synthesis of thylakoid lipids [149, 150].…”

Section: Control Of Transbilayer Lipid Asymmetry By Atp-driven Lipmentioning

confidence: 99%

Lipid somersaults: Uncovering the mechanisms of protein-mediated lipid flipping

Pomorski

Menon

2016

Progress in Lipid Research

148

141

View full text Add to dashboard Cite

Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support diverse aspects of cellular life. Here we discuss the mechanisms by which rapid flip-flop occurs, and what role lipid flipping plays in membrane homeostasis and cell growth. We focus on conceptual aspects, highlighting mechanistic insights from biochemical and in silico experiments, and the recent, ground-breaking identification of a number of lipid scramblases.

show abstract

Section: Control Of Transbilayer Lipid Asymmetry By Atp-driven Lipmentioning

confidence: 99%

Lipid somersaults: Uncovering the mechanisms of protein-mediated lipid flipping

Pomorski

Menon

2016

Progress in Lipid Research

148

141

View full text Add to dashboard Cite

show abstract

“…In both strains, the number of expressing cells and intensity of the expression signal varied substantially for Pdr11p upon galactose induction. Several studies report similar results of heterogeneous expression within the cell culture for other proteins expressed from multicopy plasmids [ 11 , 31 – 33 ]. A likely reason is fluctuating plasmid copy numbers within the cell population [ 34 ].…”

Section: Discussionmentioning

confidence: 67%

“…Many ABC transporters have been shown to possess intrinsic ATPase activity that is stimulated in the presence of transported substrates [ 1 , 24 , 30 ]. As sterol uptake is mediated by Pdr11p [ 4 ] and facilitated by albumin [ 11 ], we tested the effect of ergosterol, cholesterol, and albumin on ATPase activity. Neither ergosterol nor cholesterol in absence and presence of albumin stimulated the ATPase activity of purified Pdr11p ( Table 2 ).…”

Section: Resultsmentioning

confidence: 99%

“…In support of this, sterol uptake increases by coexpression of Aus1p and the cell wall protein Dan1p, which (like Aus1p and Pdr11p) is upregulated under anaerobic conditions [ 10 ]. Likewise, the presence of bovine serum albumin (BSA) promotes sterol uptake implying that BSA could act as a sterol donor [ 11 ]. A second model proposes that both proteins facilitate the removal of sterol from the plasma membrane to a cytosolic acceptor, such as soluble sterol-binding proteins, or closely apposed membranes of the endoplasmic reticulum [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Purification and characterisation of the yeast plasma membrane ATP binding cassette transporter Pdr11p

et al. 2017

Self Cite

View full text Add to dashboard Cite

The ATP binding cassette (ABC) transporters Pdr11p and its paralog Aus1p are expressed under anaerobic growth conditions at the plasma membrane of the yeast Saccharomyces cerevisiae and are required for sterol uptake. However, the precise mechanism by which these ABC transporters facilitate sterol movement is unknown. In this study, an overexpression and purification procedure was developed with the aim to characterise the Pdr11p transporter. Engineering of Pdr11p variants fused at the C terminus with green fluorescent protein (Pdr11p-GFP) and containing a FLAG tag at the N terminus facilitated expression analysis and one-step purification, respectively. The detergent-solubilised and purified protein displayed a stable ATPase activity with a broad pH optimum near 7.4. Mutagenesis of the conserved lysine to methionine (K788M) in the Walker A motif abolished ATP hydrolysis. Remarkably, and in contrast to Aus1p, ATPase activity of Pdr11p was insensitive to orthovanadate and not specifically stimulated by phosphatidylserine upon reconstitution into liposomes. Our results highlight distinct differences between Pdr11p and Aus1p and create an experimental basis for further biochemical studies of both ABC transporters to elucidate their function.

show abstract

“…Other approaches rely on application of fluorescently labelled sterol analogues, which however carry bulky chemical groups that can alter sterol behavior (Sezgin et al, 2016). Moreover, yeast cells only take them up in specific mutant backgrounds or growth conditions (Jacquier and Schneiter, 2012;Marek et al, 2014). Domain 4 (D4) of the bacterial toxin perfringolysin O (PFO), which binds membranes containing ≥30 mol% sterols and can be expressed in cells with no obvious toxicity, offers an interesting alternative (Shimada et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Sterol flow between the plasma membrane and the endosome is regulated by the LAM family protein Ltc1

Marek

Vincenzetti

2019

Preprint

Self Cite

View full text Add to dashboard Cite

Sterols are crucial components of biological membranes that help maintain membrane integrity and regulate various processes such as endocytosis, protein oligomerization and signaling. Although synthetized in the ER, sterols are at highest concentrations at the plasma membrane (PM) in all eukaryotic organisms. Here, by applying a genetically encoded sterol biosensor (D4H), we visualize a sterol flow between PM and endosomes in the fission yeast Schizosaccharomyces pombe. While D4H is detected at the PM during steady-state growth, inhibition of Arp2/3-dependent F-actin assembly unexpectedly promotes the reversible re-localization of the probe to internal sterol rich compartments (STRIC), as shown by correlative light-electron microscopy. Time-lapse imaging identifies STRIC as a late secretory, endosomal compartment labelled by the synaptobrevin Syb1. Retrograde sterol internalization to STRIC is independent of endocytosis or an intact Golgi. Instead, it depends on Ltc1, a LAM/StARkin-family protein that localizes to ER-PM contact sites. In ltc1Δ, sterols over-accumulate at the PM, which forms extended ER-interacting invaginations, indicating that sterol transfer by Ltc1 contributes to PM size homeostasis. Anterograde sterol movement from STRIC is independent of canonical vesicular trafficking components but requires Arp2/3 activity, suggesting a novel physiological role for this complex. Thus, transfer routes orthogonal to vesicular trafficking govern the retrograde and anterograde flow of sterols in the cell.

show abstract

Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast

Cited by 16 publications

References 42 publications

Lipid somersaults: Uncovering the mechanisms of protein-mediated lipid flipping

Lipid somersaults: Uncovering the mechanisms of protein-mediated lipid flipping

Purification and characterisation of the yeast plasma membrane ATP binding cassette transporter Pdr11p

Sterol flow between the plasma membrane and the endosome is regulated by the LAM family protein Ltc1

Contact Info

Product

Resources

About