β Cells led astray by transcription factors and the company they keep.

Pancreatic β cells have one of the highest protein secretion burdens in the body, as these cells must synthesize and secrete insulin in proportion to postprandial rises in blood glucose. Remarkably, it is now becoming clear that adult β cells retain plasticity and can dedifferentiate into embryonic fates or adopt alternate islet endocrine cell identities. This property is especially important, because changes in cell fate alter β cell function and could form the basis for defects in insulin secretion that occur early in the pathogenesis of the most prevalent form of β cell dysfunction, type 2 diabetes. In this issue, three different studies provide complementary perspectives on how the transcription factors NK2 homeobox 2 (NKX2.2), paired box 6 (PAX6), and LIM domain-binding protein 1 (LDB1) serve to maintain mature adult β cell identity, revealing clues as to how adult β cells can partially dedifferentiate or become reprogrammed into other islet endocrine cells.