Dataset Information

Bovine Liver Membrane Preparation

ABSTRACT: We optimized an SDS depletion protocol involving KCl to precipitate the surfactant from intact proteins in the presence of urea at high pH. Provided is a comparison of 4 samples preciipitated at low pH (8) vs high pH (12), with (8 M) vs without (0 M) urea.

INSTRUMENT(S):

ORGANISM(S): Bos Taurus (bovine)

TISSUE(S): Liver

SUBMITTER: Alan Doucette

LAB HEAD: Alan A Doucette

PROVIDER: PXD061512 | Pride | 2025-08-04

REPOSITORIES: Pride

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Publications

SDS Depletion from Intact Membrane Proteins by KCl Precipitation Ahead of Mass Spectrometry Analysis.

Iranpour Tania T Mirimba Mapenzi M Shenouda Chloe C Lynch Adam A Doucette Alan A AA

Proteomes 20250702 3

<h4>Background</h4>Membrane proteins are preferentially solubilized with sodium dodecyl sulfate (SDS), which necessitates a purification protocol to deplete the surfactant prior to mass spectrometry analysis. However, maintaining solubility of intact membrane proteins is challenged in an SDS-free environment. SDS precipitation with potassium salts (KCl) offers a potentially viable workflow to deplete SDS and permit proteoform analysis. The purpose of this study is to devise a robust detergent-ba ...[more]

PMID: 40700274

Similar Datasets

Project description:Exposure of Saccharomyces cerevisiae to alkaline pH represents a stress condition that generates a compensatory reaction. Here we examine a possible role of the protein kinase-A (PKA) pathway in this response. The phenotypic analysis reveals that mutations that activate the PKA pathway (ira1 ira2, bcy1) tend to cause sensitivity to alkaline pH, whereas its deactivation develops tolerance to this stress. We observe that alkalinization causes a transient decrease in cAMP, the main regulator of the pathway. Alkaline pH causes rapid nuclear localization of the PKA-regulated Msn2 transcription factor which, together with Msn4, mediates a general stress response by binding to STRE sequences in many promoters. Consequently, a synthetic STRE-LacZ reporter shows a rapid induction in response to alkaline stress. An msn2 msn4 mutant is sensitive to alkaline pH, and transcriptomic analysis reveals that after 10 minutes of alkaline stress, the expression of many induced genes (47%) depends, at least in part, on the presence of Msn2 and Msn4. Taken together, these results demonstrate that inhibition of the PKA pathway by alkaline pH represents a substantial part of the adaptive response to this kind of stress and that this response involves Msn2/Msn4-mediated gene remodeling. However, the relevance of attenuation of PKA in high pH tolerance is not restricted to regulation of Msn2 function. Eight samples were analyzed: WT and the MCY5278 mutant strain, lacking both Msn2 and Msn4, in the presence of 20 mM KOH (pH 8) and in the presence of 20 mM KCl (non-induced conditions) for 10 and 30 min of stress. 2 biological replicates were analyzed for each condition, and dye-swapping was carried out for each comparison of samples. We compared the expression profiles of: 1) WT +KOH vs. WT +KCl after 10 min 2) msn2 msn4 mutant +KOH vs. msn2 msn4 +KCl after 10 min 3)WT +KOH vs. WT +KCl after 30 min 4) msn2 msn4 mutant +KOH vs. msn2 msn4 +KCl after 30 min Total number of chips analyzed: 16.

Project description:Human Umbilical Vein Endothelial Cells pooled from several donors, were purchased from Lonza and cultured in FBS reduced Endopan 3 media. HUVEC cells of passages 5-10 were used for experiments. MPO treatment was performed with protein purified from human blood (Planta) and at 1 μg/ml final concentration. Immunoprecipitation was performed from isolated nuclei (after 8 hours MPO treatment), non-treated cells were used as negative control. For immunoprecipitation antibody against MPO (Calbiochem, 475915) was used. Cell nuclei were isolated by incubating cells for 15 min on ice in NIB buffer (15 mM Tris-HCL pH 7.5, 60 mM KCl, 15 mM NaCl, 5 mM MgCl2, 1 mM CaCl2, 250 mM sucrose) containing 0.3% NP-40. Nuclei were pelleted for 5 min 800 × g at 4 °C, washed twice in the same buffer, lysed for 10 min on ice in IP buffer (150 mM LiCl, 50 mM Tris-HCl pH 7.5, 1 mM EDTA, 0.5% Empigen) freshly supplemented with 2 mM sodium vanadate, 1× protease inhibitor cocktail (Roche), PMSF (10 µl), 0,5 mM DTT, and 50 units Benzonase per ml of IP buffer, before preclearing cell debris by centrifugation at >15,000 × g at 4 °C. Finally, 1 mg of the lysate was incubated with anti-MPO antisera overnight at 4 °C. Magnetic beads (Active Motif) were then washed once with 1× PBS-Tween and combined with the antibody-lysate mixture. Following a 2-h incubation at 4 °C, beads were separated on a magnetic rack and washed 5×, 5 min each in wash buffer (150 mM KCl, 5 mM MgCl2, 50 mM Tris-HCl pH 7.5, 0.5% NP-40) and another two times in wash buffer without NP-40. Captured proteins were predigested and eluted from the beads using digestion buffer (2 M Urea, 50 mM Tris-HCl pH 7.5, 1 mM DTT) supplemented with trypsin and eluted from the beads with elution buffer (2 M Urea, 50 mM Tris-HCl pH 7.5, 5 mM chloroacetamide) supplemented with trypsin and LysC, before subjected to mass-spectrometry on a Q-Exactive Plus Orbitrap platform coupled to an EASY nLC (Thermo Scientific). Peptides were loaded in solvent A (0.1% formic acid in water) onto an in-house packed analytical column (50 cm length, 75 µm I.D., filled with 2.7 µm Poroshell EC120 C1; Agilent)

			Action	DRS
	allPeptides.txt	Txt
	pH12_no_urea_1.index	Other
	pH12_no_urea_1.raw	Raw
	pH12_no_urea_2.index	Other
	pH12_no_urea_2.raw	Raw