Editorial: Signaling Proteins for Endosomal and Lysosomal Function

Cells control their activity, in coordination with signal cues, by modulating the levels of plasma membrane receptors and transporters by the action of endosomes and lysosomes. This process is initiated by ubiquitination of cell surface receptors and transporters (cargoes), followed by their internalization by endocytosis. These cargoes are then transported via vesicular trafficking to early endosomes and, depending on external cues, they are either recycled back to the plasma membrane or degraded in late endosomal or lysosomal compartments. Given the heterogeneity of endosomes and lysosomes, due to their specific protein and lipid composition, subcellular localization, and membrane shape, it is not surprising they have also arisen as dynamic signaling platforms. Endosomes and lysosomes elicit an array of signaling events, including regulation of gene expression, cell survival, cytoskeletal organization, nutrient uptake, lipid transport, and autophagy (Lefebvre et al., 2018; Norris and Grant, 2020; Yang and Wang, 2021). These organelles can also be hijacked by pathogen effector proteins, facilitating pathogen survival (Asrat et al., 2014).