Issues

Exosomes are a subpopulation of extracellular vesicles that contain a highly sorted set of protein and RNA cargos. Despite broad interest, the molecular mechanisms by which cargos are sorted into exosomes remain incomplete. In this study, Ngo et al. identify the selective autophagy receptor p62 as a quality control factor that selectively sorts cargo into exosomes.

Park et al. show that Drosophila Abi, a regulator of actin cytoskeletal dynamics, controls blood cell homeostasis by activating Notch signaling through clathrin-mediated receptor endocytosis. This regulatory process is promoted by PTP61F-mediated Abi dephosphorylation but antagonized by Abl-mediated Abi phosphorylation, revealing a reversible phosphorylation switch that integrates actin remodeling, endocytosis, and Notch signaling.

Richards et al. use live imaging of the mouse skin to visualize how melanocyte precursors (melanoblasts) migrate between adherent epithelial cells as they colonize the epidermis. They show melanoblasts form dynamic E-cadherin–based attachments to surrounding keratinocytes that are required to stabilize migratory protrusions and sustain their long-distance migration.

Medina, Chang et al. introduce a new method based on the Surface Morphometrics pipeline to measure global and local thicknesses of organellar membranes from cellular cryo-electron tomography data. They identified differences between organelles and membrane protein-specific changes in the cellular context.

Guo et al. introduce SynSeg, a method that eliminates manual annotation by training deep learning models on synthetic data from abstracted “primitives.” This robustly segments diverse subcellular structures, enabling high-throughput, quantitative analysis of novel, disease-related cellular phenotypes.