Small-scale recycling of cell proteins by late-stage cell compartments

Distinct autophagic mechanisms control cytosolic protein delivery to late endosomes.

• A microautophagy-like process delivers soluble cytosolic proteins to late endosomes/multivesicular bodies.
• This process is selective and different from chaperone-mediated autophagy that occurs in lysosomes.
• Endosomal microautophagy relies on the ESCRT I and III systems for vesicle formation.
• Protein selection for this process is mediated by the chaperone hsc70, requiring its cationic domain for interactions with the endosomal membrane.
• Endosomal microautophagy may share molecular components with both endocytic and autophagic pathways.

Simplified