Efficient adhesion-based plasma membrane isolation for cell surface N-glycan analysis

Cell surface glycans are involved in many physiological processes, including cell recognition. However, isolating plasma membranes for glycan analysis has been challenging. Traditional methods often include whole-cell lysates or whole membranes, which can introduce contamination from other organelles. This contamination limits the ability to study cell surface glycans specifically. Prior research has shown that endoplasmic reticulum-derived glycans can interfere with surface glycan detection. No prior work had resolved how to isolate plasma membranes without contamination. This gap motivated the development of a new adhesion-based isolation method. The goal is to improve the accuracy of cell surface glycan profiling. The need for a cleaner plasma membrane preparation is clear. This study addresses that need with a novel approach.

The aim of this study is to develop an efficient method for isolating plasma membranes to analyze cell surface N-glycans. The researchers sought to reduce contamination from intracellular organelles. They focused on a method that could specifically capture plasma membranes. The motivation is to improve the detection of complex-type N-glycans on cell surfaces. High-mannose glycans, often from the endoplasmic reticulum, are a known issue in current methods. The study proposes using an adhesion-based approach to isolate plasma membranes. This method could enable more accurate glycan profiling. The researchers aim to validate the effectiveness of this new isolation technique.

Cells were cultured on polylysine-coated glass plates to promote adhesion. Hypotonic pressure was used to rupture the cells and expose the plasma membrane. After rupture, the plates were washed to remove intracellular organelles. Fluorescence imaging confirmed that only plasma membranes remained attached. The remaining membrane fraction was treated with trypsin to digest glycoproteins. N-glycans were then released from the glycopeptides for analysis. MALDI-TOF mass spectrometry and HPLC were used to profile the N-glycans. This adhesion-based method was compared to traditional approaches to assess its effectiveness.

The adhesion-based method significantly reduced contamination from high-mannose glycans. Fluorescence imaging confirmed that only plasma membranes remained after washing. MALDI-TOF and HPLC analysis showed increased detection of complex-type N-glycans. The method enabled more accurate profiling of cell surface glycans. High-mannose glycans, typically from the endoplasmic reticulum, were minimized. The method successfully detected changes in glycan profiles after mannosidase inhibition. This approach outperformed traditional methods in purity and specificity. The results suggest this method is suitable for surface glycan analysis.

The adhesion-based plasma membrane isolation method effectively reduces contamination. This approach allows for more accurate detection of complex-type N-glycans on cell surfaces. The method successfully isolates plasma membranes without intracellular organelle contamination. High-mannose glycans from the endoplasmic reticulum are significantly reduced. The method was validated using fluorescence imaging and mass spectrometry. The results show this method is suitable for analyzing cell surface glycan changes. The study demonstrates the potential of this technique for glycan profiling. The findings suggest this method improves the specificity of surface glycan analysis.