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Imporved method for isolation of plasma membrane on cationic beads. Membranes from Dictyostelium discoideum
Abstract:
The plasma membrane from Dictyostelium discoideum was routinely purified 35-fold by an improved technique using beads coated with positively charged polymers. Cells were attached to the beads and bare regions between the cells were neutralized with a polyanion. The neutralization decreased contamination of the bare regions by intracellular proteins released when cells were disrupted to leave behind beads coated by plasma membrane. The neutralization increased the purification as measured by membrane-bound 125I-labeled concanavalin A. Contamination by markers for various intracellular components was markedly decreased. Various bare-site neutralization reagents were evaluated and gave different results depending upon their charge density and molecular weight. The pH of the neutralization was critical. The optimum pH for cell attachment to beads, 5.0, had little effect as regard bare-site neutralization. A new procedure is given that optimizes the essential features for the plasma membrane isolation on beads.
Insights
This study introduces an improved method for purifying plasma membranes from Dictyostelium discoideum using charged polymer-coated beads. This technique significantly reduces intracellular protein contamination, enhancing membrane purity for research.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Plasma membrane purification is crucial for studying cellular functions.
- Existing methods for Dictyostelium discoideum plasma membrane isolation often suffer from intracellular contamination.
- Improved techniques are needed to obtain highly pure plasma membrane fractions.
Purpose of the Study:
- To develop and optimize an enhanced technique for purifying plasma membranes from Dictyostelium discoideum.
- To reduce contamination by intracellular proteins during plasma membrane isolation.
- To improve the overall yield and purity of isolated plasma membranes.
Main Methods:
- Utilized positively charged polymer-coated beads for cell attachment.
- Employed a polyanion for neutralization of bare regions between cells after disruption.
- Evaluated various neutralization reagents, their properties (charge density, molecular weight), and pH.
- Measured purification efficiency using membrane-bound 125I-labeled concanavalin A and intracellular marker contamination.
Main Results:
- Achieved a 35-fold purification of Dictyostelium discoideum plasma membranes.
- Demonstrated significant reduction in intracellular protein contamination through polyanion neutralization.
- Identified critical parameters including reagent properties and pH for effective bare-site neutralization.
- Optimized the procedure for essential plasma membrane isolation features on beads.
Conclusions:
- The improved bead-based technique offers a highly effective method for isolating pure plasma membranes from Dictyostelium discoideum.
- Polyanion neutralization is key to minimizing contamination and enhancing purification efficiency.
- This optimized procedure provides a robust tool for cell biology and biochemical research.