Laiman et al. discover that GSK3α, but not GSK3β, phosphorylates dynamin-2 to unleash the Bin1 inhibition and promotes GLUT4 endocytosis in skeletal muscle. Importantly, pharmacological inhibition of GSK3α improves insulin sensitivity and glucose tolerance in diet-induced diabetic mice, highlighting GSK3α as a therapeutic target for metabolic disorders.

Pacheco et al. demonstrate that unbound PI(4,5)P2 diffusion in the PM is rapid and is not slowed by the majority of PI(4,5)P2-dependent PM complexes found there, such as clathrin-coated structures and focal adhesions.

Combining live TIRF microscopy and fluorescently tagged fibronectin, the authors show that fibronectin secretion by fibroblasts occurs preferentially at leading edge protrusions stabilized by mature focal adhesions and that fibronectin deposition requires both intact microtubules and myosin II contractility.

Milas et al. use mechanical and optical perturbation to show the requirement of cell–cell contact between somatic follicle cells and the oocyte in the Drosophila egg chamber for maintaining Par protein polarity and posterior oskar mRNA localization.

Huang and Chen et al. find that inhibition of ATM in cancer cells induces uptake of branched-chain amino acids via macropinocytosis. This work also reveals that macropinocytosis is a metabolic vulnerability of cancer cells treated with ATM inhibitors.

Axon maintenance is critical to sustaining a functional nervous system as animals age. Glia contribute to axon maintenance, but precisely how is not well characterized. This work identifies a battery of glial genes that regulate axon support. These genes provide insight into in vivo mechanisms of axon maintenance and may help explain how glial dysfunction leads to neurodegeneration.

Egg–sperm fusion is the climax of fertilization. In vertebrates, the molecules that directly mediate egg–sperm merger and how this process occurs have been the holy grail of fertilization. Here, Brukman, Nakajima et al. demonstrate that the docking protein IZUMO1 from mouse can merge mammalian cells.