Microcystin-LY is a toxic cyanobacterial compound primarily known for its hepatotoxic effects. It has been used in scientific research to study liver cell damage and the mechanisms of toxin-induced hepatotoxicity. Due to its ability to inhibit protein phosphatases 1 and 2A, it serves as a tool in cellular and molecular biology to investigate signal transduction pathways, cell cycle regulation, and apoptosis. Its presence in water systems is monitored as an indicator of harmful algal blooms, contributing to environmental and public health risk assessments. Because of its high toxicity, it is not used in industrial or commercial applications outside of controlled research settings.