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Irs-2 coordinates Igf-1 receptor-mediated beta-cell development and peripheral insulin signalling
D J Withers1, D J Burks, H H Towery
1Howard Hughes Medical Institute, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, Massachusetts 02215, USA.
Nature Genetics
|September 2, 1999
Summary
Insulin receptor substrates (IRS) are vital for growth and glucose regulation. IRS-1 is key for growth, while IRS-2 is crucial for beta-cell function and insulin resistance, integrating insulin and IGF-1 signals.
Area of Science:
- Endocrinology
- Molecular Biology
- Genetics
Background:
- Insulin receptor substrates (IRS proteins) mediate insulin and IGF-1 signaling.
- These pathways regulate glucose homeostasis, cell growth, and survival.
Purpose of the Study:
- To investigate the distinct and overlapping roles of IRS-1 and IRS-2 in growth and glucose metabolism.
- To elucidate the role of IGF-1 receptor signaling in pancreatic beta-cells via IRS-2.
Main Methods:
- Intercrossing mice heterozygous for null alleles of Irs1 and Irs2.
- Intercrossing mice heterozygous for null alleles of Igf1r and Irs2.
- Analysis of growth and glucose metabolism in resulting viable genotypes.
Main Results:
- IRS-1 and IRS-2 are essential for embryonic and postnatal growth, with IRS-1 playing a predominant role.
- Both IRS-1 and IRS-2 are involved in peripheral carbohydrate metabolism, but IRS-2 is critical for beta-cell development and compensating for insulin resistance.
- IGF-1 receptors promote beta-cell development and survival through the IRS-2 signaling pathway.
Conclusions:
- IRS-2 integrates peripheral insulin effects with pancreatic IGF-1 signaling to maintain glucose homeostasis.
- Differential roles of IRS-1 and IRS-2 highlight their specific contributions to metabolic regulation and growth.
- Targeting IRS-2 may offer therapeutic strategies for metabolic disorders.