Mannóz6foszfát

Mannóz6foszfát, also known as mannose-6-phosphate or M6P, is a phosphorylated sugar molecule. It is a key intermediate in the metabolism of mannose. In eukaryotic cells, M6P plays a crucial role in the sorting and trafficking of proteins, particularly lysosomal enzymes.

The synthesis of M6P occurs in the Golgi apparatus. Mannose residues on newly synthesized proteins destined for lysosomes are tagged with M6P. This tagging is a specific enzymatic modification. This M6P tag then serves as a recognition signal for M6P receptors, which are located in the membranes of the Golgi and endosomes.

These M6P receptors bind to the M6P-tagged proteins and direct them to the late endosomes, which eventually mature into lysosomes. This mechanism ensures that lysosomal enzymes are delivered to their correct cellular destination, where they are responsible for breaking down waste materials and cellular debris. Defects in the M6P tagging or receptor binding pathway can lead to serious genetic disorders known as lysosomal storage diseases, where specific enzymes are not delivered to the lysosomes, causing the accumulation of undigested substances within cells. M6P is therefore essential for maintaining cellular homeostasis and proper lysosomal function.