Final answer:
The Sorting nexin (SNX) complex is essential in membrane sorting, where it binds to phosphoinositide lipids, orchestrating the retrograde transport of proteins from endosomes to the trans-Golgi network or plasma membrane.
Step-by-step explanation:
The role of the Sorting nexin (SNX) complex is involved in membrane sorting and trafficking within cells. The SNX complex binds to phosphoinositide lipids on organelle membranes, playing a crucial role in the determination of the direction of vesicular traffic. Their main responsibility is to regulate the endosomal sorting of proteins for either recycling to the plasma membrane or degradation in lysosomes. The SNX complex participates in the retrograde transport, in which they retrieve certain transmembrane proteins from endosomes to the trans-Golgi network (TGN) or plasma membrane. Thus, the correct answer to the question is D. Membrane sorting; Phosphoinositide lipids.