Mannose 6 phosphate (M6P) is a sequence tag that plays a pivotal role in transporting proteins from the Golgi complex and cell surface to the lysosome. The M6P sequence is tagged to the N-linked oligosaccharides of lysosomal hydrolases as they traverse the cis-Golgi apparatus. Upon M6P-tagging, these proteins are targeted to the late endosome via vesicular transport. Low pH conditions there mediate the dissociation of a M6P Receptor from its ligand, allowing recycling of the M6P sequences.
