Send to

Choose Destination
See comment in PubMed Commons below
Sci STKE. 2005 Jan 25;2005(268):pe2.

Diabetes outfoxed by GLP-1?

Author information

  • 1Department of Physiology and Neuroscience, New York University School of Medicine, New York, NY 10016, USA. <>


Foxo1, a member of the Fox0 subfamily of winged-helix forkhead transcription factors, is a target of insulin and insulin-like growth factor-1 (IGF-1) signal transduction pathways that activate protein kinase B (PKB) in pancreatic beta cells. Foxo1 is a substrate for PKB, and its phosphorylation results in nuclear exclusion with concomitant alterations in gene expression that are important to cellular growth and differentiation. Because activation of PKB can require insulin receptor substrate proteins (IRS-1 and IRS-2) and phosphatidylinositol 3-kinase (PI3K), it is of interest to determine whether the activity of Foxo1 is also regulated by heterotrimeric G protein-coupled receptors (GPCRs) with IRS-1 or -2, PI3K, or PKB signaling potential. Indeed, studies of beta cells have demonstrated that activation of a GPCR for the blood glucose-lowering hormone GLP-1 leads to major alterations of IRS-2, PI3K, and PKB activity. By promoting nuclear exclusion of Foxo1 in a PKB-mediated manner, GLP-1 may up-regulate the expression of a homeodomain transcription factor (PDX-1) that serves as a master regulator of beta-cell growth and differentiation. This STKE Perspective summarizes signaling properties of GLP-1 that may explain its ability to increase beta-cell mass, to increase pancreatic insulin secretory capacity, and to lower levels of blood glucose in type 2 diabetic subjects.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center