A Method For Estimating The Cholesterol Affinity Of Integral Membrane Proteins From Experimental Data DOI Creative Commons
Theodore L. Steck, S. M. Ali Tabei,

Yvonne Lange

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Окт. 3, 2023

ABSTRACT The cholesterol affinities of many integral plasma membrane proteins have been estimated by molecular computation. However, these values lack experimental confirmation. We therefore developed a simple mathematical model to extract sterol affinity constants and stoichiometries from published isotherms for the dependence activity such on concentration. binding curves are sigmoidal with strongly-lagged thresholds attributable competition bilayer phospholipids. provided that matched data using association Three oligomeric transporters were found bind without cooperativity dimensionless 35 Kir3.4* 100 both Kir2 GAT transporter. (The corresponding ρG° -8.8, -11.4 KJ/mol, respectively.) These significantly lower than those phospholipids which range ∼100 6,000. BK channel, nicotinic acetylcholine receptor M192I mutant appear multiple molecules cooperatively (n = 2 or 4) subunit 563, 950 700, respectively. predicts three less avid approximately half-saturated in their native membranes; hence, sensitive variations vivo. more would be nearly saturated method can applied any protein other ligand there reasonable estimates

Язык: Английский

Regulation of cellular cholesterol distribution via non-vesicular lipid transport at ER-Golgi contact sites DOI Creative Commons
Tomoki Naito, Haoning Yang, Dylan Hong Zheng Koh

и другие.

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Сен. 21, 2023

Abstract Abnormal distribution of cellular cholesterol is associated with numerous diseases, including cardiovascular and neurodegenerative diseases. Regulated transport critical for maintaining its proper in the cell, yet underlying mechanisms remain unclear. Here, we show that lipid transfer proteins, namely ORP9, OSBP, GRAMD1s/Asters (GRAMD1a/GRAMD1b/GRAMD1c), control non-vesicular at points contact between ER trans-Golgi network (TGN), thereby distribution. ORP9 localizes to TGN via interaction tandem α-helices ORP10/ORP11. extracts PI4P from prevent overaccumulation suppresses OSBP-mediated PI4P-driven Golgi. By contrast, GRAMD1s excess Golgi ER, preventing build-up. Cells lacking exhibit accumulation Golgi, which further enhanced by additional depletion major plasma membrane. This accompanied chronic activation SREBP-2 signalling pathway. Our findings reveal importance regulated ER-Golgi contacts homeostasis.

Язык: Английский

Процитировано

22
Visualization of accessible cholesterol using a GRAM domain-based biosensor DOI Creative Commons
Dylan Hong Zheng Koh, Tomoki Naito,

Minyoung Na

и другие.

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Окт. 25, 2023

Cholesterol is important for membrane integrity and cell signaling, dysregulation of the distribution cellular cholesterol associated with numerous diseases, including neurodegenerative disorders. While regulated transport a specific pool cholesterol, known as "accessible cholesterol", contributes to maintenance homeostasis, tools monitor accessible in live cells remain limited. Here, we engineer highly sensitive biosensor by taking advantage cholesterol-sensing element (the GRAM domain) an evolutionarily conserved lipid transfer protein, GRAMD1b. Using this biosensor, which call GRAM-W, successfully visualize real time many different types, human keratinocytes iPSC-derived neurons, show differential dependencies on biosynthesis uptake maintaining levels cholesterol. Furthermore, combine GRAM-W dimerization-dependent fluorescent protein (ddFP) establish strategy ultrasensitive detection plasma These will allow us obtain insights into molecular mechanisms regulated.

Язык: Английский

Процитировано

14
HIV-1 Gag targeting to the plasma membrane reorganizes sphingomyelin-rich and cholesterol-rich lipid domains DOI Creative Commons
Nario Tomishige,

Maaz Bin Nasim,

Motohide Murate

и другие.

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Ноя. 21, 2023

Abstract Although the human immunodeficiency virus type 1 lipid envelope has been reported to be enriched with host cell sphingomyelin and cholesterol, molecular mechanism of enrichment is not well understood. Viral Gag protein plays a central role in budding. Here, we report interaction between lipids using different quantitative super-resolution microscopy techniques combination specific probes that bind endogenous cholesterol. Our results indicate inner leaflet plasma membrane colocalizes outer sphingomyelin-rich domains cholesterol-rich domains, enlarges strongly restricts mobility domains. Moreover, multimerization induces close proximity curvature-dependent manner. study suggests binds, coalesces, reorganizes pre-existing during assembly.

Язык: Английский

Процитировано

12
Is reverse cholesterol transport regulated by active cholesterol? DOI Creative Commons
Theodore L. Steck,

Yvonne Lange

Journal of Lipid Research, Год журнала: 2023, Номер 64(6), С. 100385 - 100385

Опубликована: Май 10, 2023

This review considers the hypothesis that a small portion of plasma membrane cholesterol regulates reverse transport in coordination with overall cellular homeostasis. It appears almost all is held stoichiometric complexes bilayer phospholipids. The minor fraction exceeds complexation capacity phospholipids called active cholesterol. has an elevated chemical activity and circulates among organelles. also moves down its gradient to HDL, facilitated by ABCA1, ABCG1, SR-BI. ABCA1 initiates this process perturbing organization bilayer, thereby priming for translocation apoA-I form nascent HDL. excess sterol activated itself follow ABCG1 similarly rearranges sends additional while SR-BI simply facilitates equilibration between membranes proteins. Active flows downhill cytoplasmic where it serves both as feedback signal homeostatic ER proteins substrate synthesis mitochondrial 27-hydroxycholesterol (27HC). 27HC binds LXR promotes expression aforementioned 27HC-LXR activates competitively displacing inhibitor, unliganded LXR. § Considerable indirect evidence suggests transport. Direct tests novel are proposed.

Язык: Английский

Процитировано

10
How active cholesterol coordinates cell cholesterol homeostasis: Test of a hypothesis DOI Creative Commons

Yvonne Lange,

Theodore L. Steck

Progress in Lipid Research, Год журнала: 2024, Номер 96, С. 101304 - 101304

Опубликована: Ноя. 1, 2024

How do cells coordinate the diverse elements that regulate their cholesterol homeostasis? Our model postulates membrane forms simple complexes with bilayer phospholipids. The phospholipids in plasma are of high affinity; consequently, they fully complexed sterol. This sets resting level cholesterol. Cholesterol excess stoichiometric equivalence point these has chemical activity; we refer to it as active It equilibrates low affinity intracellular membranes where serves a negative feedback signal manifold regulatory proteins rein ongoing accretion. We tested review literature regarding fourteen homeostatic enterocytes. provided strong albeit indirect support for following hypothesis. Active inhibits uptake and biosynthesis by suppressing both expression activity gene products activated SREBP-2; namely, HMGCR, LDLR NPC1L1. also reduces free cell serving substrate its esterification ACAT synthesis side-chain oxysterols, 27-hydroxycholesterol particular. oxysterols drive depletion promoting destruction HMGCR stimulating sterol well activation LXR. latter fosters multiple proteins, including four transporters which is likely substrate. By nulling cholesterol, maintains cellular at physiologic set point.

Язык: Английский

Процитировано

2
Estimating the Cholesterol Affinity of Integral Membrane Proteins from Experimental Data DOI Creative Commons
Theodore L. Steck, S. M. Ali Tabei,

Yvonne Lange

и другие.

Biochemistry, Год журнала: 2023, Номер 63(1), С. 19 - 26

Опубликована: Дек. 15, 2023

The cholesterol affinities of many integral plasma membrane proteins have been estimated by molecular computation. However, these values lack experimental confirmation. We therefore developed a simple mathematical model to extract sterol affinity constants and stoichiometries from published isotherms for the dependence activity such on concentration. binding curves are sigmoidal, with strongly lagged thresholds attributable competition bilayer phospholipids. provided that matched data using association Three oligomeric transporters were found bind without cooperativity, dimensionless 35 Kir3.4* 100 both Kir2 GAT transporter. (The corresponding ΔG° −8.8, −11.4, −11.4 kJ/mol, respectively). These significantly lower than those phospholipids, which range ∼100 6000. BK channel, nicotinic acetylcholine receptor, M192I mutant appear multiple molecules cooperatively (n = 2 or 4), subunit 563, 950, 700, respectively. predicts three less avid approximately half-saturated in their native membranes; hence, they sensitive variations vivo. more would be nearly saturated method can applied any protein other ligands there reasonable estimates

Язык: Английский

Процитировано

5
Serum opacity factor normalizes erythrocyte morphology in Scarb1−/− mice in an HDL-free cholesterol-dependent way DOI Creative Commons
Ziyi Wang,

Dedipya Yelamanchili,

Jing Liu

и другие.

Journal of Lipid Research, Год журнала: 2023, Номер 64(11), С. 100456 - 100456

Опубликована: Окт. 10, 2023

Compared to wild-type (WT) mice, high-density lipoprotein (HDL)-receptor-deficient (Scarb1-/-) mice have higher plasma levels of free cholesterol (FC)-rich HDL and exhibit multiple pathologies associated with a high mol% FC in ovaries, platelets, erythrocytes which are reversed by lowering HDL. Bacterial serum opacity factor (SOF) catalyzes the opacification targeting quantitatively converting neo (HDL remnant), ester-rich microemulsion, lipid-free APOA1. SOF delivery an adeno-associated virus (AAVSOF) constitutively lowers HDL-FC reverses female infertility Scarb1-/- HDL-dependent way. We tested whether AAVSOF will normalize erythrocyte morphology dependent determined content (mol%) three groups—WT, untreated (control), receiving AAVSOF—and correlated these their respective HDL-mol% FC. Plasma-, HDL- tissue-lipid compositions were also determined. Plasma- positively across all groups. Among treatment normalized reticulocyte number, erythrocyte-mol% Erythrocyte-mol% both number reticulocytes abnormal erythrocytes. reduced extravascular tissues lesser extent. spontaneously transfers from cell membranes. erythrocyte-FC normalizes lipid composition reducing

Язык: Английский

Процитировано

1
A Method For Estimating The Cholesterol Affinity Of Integral Membrane Proteins From Experimental Data DOI Creative Commons
Theodore L. Steck, S. M. Ali Tabei,

Yvonne Lange

и другие.

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Окт. 3, 2023

ABSTRACT The cholesterol affinities of many integral plasma membrane proteins have been estimated by molecular computation. However, these values lack experimental confirmation. We therefore developed a simple mathematical model to extract sterol affinity constants and stoichiometries from published isotherms for the dependence activity such on concentration. binding curves are sigmoidal with strongly-lagged thresholds attributable competition bilayer phospholipids. provided that matched data using association Three oligomeric transporters were found bind without cooperativity dimensionless 35 Kir3.4* 100 both Kir2 GAT transporter. (The corresponding ρG° -8.8, -11.4 KJ/mol, respectively.) These significantly lower than those phospholipids which range ∼100 6,000. BK channel, nicotinic acetylcholine receptor M192I mutant appear multiple molecules cooperatively (n = 2 or 4) subunit 563, 950 700, respectively. predicts three less avid approximately half-saturated in their native membranes; hence, sensitive variations vivo. more would be nearly saturated method can applied any protein other ligand there reasonable estimates

Язык: Английский

Процитировано

0