X-box–binding protein-1 (XBP-1) increases insulin sensitivity by activating endoplasmic reticulum capacity during feeding to control glucose homeostasis, a function severely impaired in obesity. But XBP-1 can also increase glucose tolerance in obese and diabetic mice by blocking gluconeogenesis, independent of its effect on insulin sensitivity, opening new avenues for type 2 diabetes therapies (pages 356–365).
- Kohjiro Ueki
- Takashi Kadowaki
