Mannose-6-phosphate is a sugar molecule that plays a crucial role in cellular processes. It is primarily involved in the tagging of proteins for transport to the lysosome, an organelle responsible for breaking down waste materials and cellular debris. This tagging ensures that enzymes and other proteins reach their correct destination within the cell. The formation of mannose-6-phosphate occurs during the modification of proteins in the Golgi apparatus. When proteins are tagged with this molecule, they are recognized by specific receptors that facilitate their delivery to the lysosome. This process is essential for maintaining cellular health and function.