Phospho-Protein Extraction Buffer I is primarily used in molecular biology and biochemistry research to isolate phospho-proteins from cell and tissue samples. It is particularly valuable in studying cell signaling pathways, as it enables the extraction of phosphorylated proteins while maintaining their phosphorylation state. This buffer is often employed in Western blotting, immunoprecipitation, and other protein analysis techniques to investigate protein phosphorylation events, which are critical in understanding cellular processes like growth, differentiation, and apoptosis. Its effectiveness in preserving protein integrity and phosphorylation status makes it a key tool in proteomics and cancer research.