GGA1 controls enzyme sorting and cell cleanup by changing lipid balance in the cell’s sorting center

Sphingomyelin (SM) is exposed on the cytoplasmic surface of the trans-Golgi network by the action of the protein GGA1.

• The exposure of SM is influenced by the curvature of membranes and cholesterol levels.
• SM exposure occurs simultaneously with the departure of mannose 6-phosphate receptors from the trans-Golgi network.
• This process is important for the proper trafficking of lysosomal enzymes.
• SM is also transferred to autophagic membranes, aiding in the fusion of autophagosomes with lysosomes.
• These results highlight a novel role for lipid remodeling in the processes of membrane trafficking and autophagy.

Simplified