KKL-35 is primarily utilized in research settings as a potent and selective inhibitor of the mitochondrial calcium uniporter (MCU). This application is crucial for studying calcium signaling pathways within cells, particularly in understanding how calcium dynamics influence cellular metabolism, apoptosis, and overall mitochondrial function. By inhibiting MCU, researchers can explore the role of mitochondrial calcium uptake in various physiological and pathological processes, including neurodegeneration, cardiovascular diseases, and cancer. Its specificity makes it a valuable tool for dissecting the complex mechanisms of calcium regulation in mitochondria, aiding in the development of potential therapeutic strategies targeting mitochondrial dysfunction.