REGULATION OF SORTING NEXINS IN ENDOSOMAL PROTEIN SORTING
Among the two possible fates that a cargo entering the early endosome may have, namely lysosomal degradation and cargo recycling, the mechanism that cells use to retrieve cargoes for recycling remain incompletely understood. The SNX3 protein, one member of a large family of phosphoinositide-binding sorting nexins (Snxs), mediates cargo retrieval from early endosomes and transport to the trans-Golgi network via retrograde pathway. There is evidence suggesting that SNX3 functions by binding to phosphatidylinositol 3-phosphate (PtdIns3P) on the endosomal membrane and recruiting a larger cargo-selective protein complex, the cytoplasmic retromer, to the membrane. Although research findings suggest that membrane targeting of SNX3 via PtdIns3P binding is regulated, the underlying mechanisms are largely unknown.
Confocal microscopy reveals co-localization pattern of SNX3 (GFP) and LAMP1 (RFP) in HeLa cells.