rs1805097 — IRS2 Gly1057Asp

IRS2 Gly1057Asp — The Longevity Variant That Requires You to Stay Lean

The insulin/IGF-1 signaling (IIS) pathway is the most conserved longevity pathway across all studied species. Reduce it in yeast, worms, flies, or mice, and lifespan extends. IRS2 — insulin receptor substrate 2 — is the critical intracellular docking protein that receives the IGF-1 receptor's signal and amplifies it through the PI3K-AKT-mTOR cascade. In mice, complete IRS2 knockout extends median lifespan by up to 20%¹¹ In mice, complete IRS2 knockout extends median lifespan by up to 20%
White MF. IRS2 integrates insulin/IGF1 signalling with metabolism, neurodegeneration and longevity. Diabetes Obes Metab. 2014. rs1805097 creates a glycine-to-aspartic acid substitution at position 1057 of the IRS2 protein — a structural shift in the C-terminal domain that alters the protein's signaling efficiency. Homozygous carriers of the Asp variant are approximately twice as likely to reach extreme old age.

The Mechanism

IRS2 sits just downstream of both the insulin receptor and the IGF-1 receptor (IGF1R). When either receptor is activated, IRS2 becomes tyrosine-phosphorylated and recruits PI3-kinase, triggering a cascade culminating in AKT and mTOR activation. This drives growth, protein synthesis, and cellular proliferation — metabolically costly processes that appear to accelerate biological aging²² accelerate biological aging
White MF. 2014.

The Gly1057Asp substitution falls within the C-terminal serine phosphorylation domain of IRS2. Position 1057 lies near a cluster of regulatory serine residues that govern IRS2 stability and interaction with downstream signaling partners. The aspartic acid substitution (negatively charged, versus neutral glycine) may subtly alter the protein's folding and its interaction with 14-3-3 proteins and E3 ubiquitin ligases — mechanisms that control IRS2 protein levels. The result appears to be modestly attenuated IIS flux, which the longevity literature uniformly associates with extended healthspan. Importantly, the fasting C-peptide levels of Asp allele carriers are inversely correlated with allele dosage in lean individuals, suggesting higher insulin sensitivity — a fundamentally different mechanism than the lifespan extension observed in IRS2 knockout mice, and one that is highly context-dependent.

The Evidence

The primary human longevity study comes from Barbieri et al. 2010³³ Barbieri et al. 2010
Barbieri M et al. The IRS2 Gly1057Asp variant is associated with human longevity. J Gerontol A Biol Sci Med Sci. 2010. Among 677 Italian participants (ages 16-104), homozygous Asp/Asp individuals were significantly overrepresented among long-lived subjects (>85 years old) compared to controls (16.7% vs 12.0%, p = .04). When focused on extreme old age (ages 96-104), Asp/Asp individuals had a 2.03-fold increased probability of reaching that age (95% CI 1.39-2.99, p = .0003). After adjusting for anthropometric and metabolic covariates, the overall longevity odds ratio was 2.07 (95% CI 1.38-3.12, p = .001), confirming the association is independent of body weight and metabolic status.

A gene-combination study Barbieri et al. 2012⁴⁴ Barbieri et al. 2012
Barbieri M et al. A/Asp/Val allele combination of IGF1R, IRS2, and UCP2 genes is associated with better metabolic profile, preserved energy expenditure parameters, and low mortality rate in longevity. Age (Dordr). 2012 examined 722 Italian subjects and found that when the IRS2-Asp allele is combined with the IGF1R longevity A-allele (rs2229765) and the UCP2 Val allele (rs659366), the longevity association is dramatically amplified: OR 3.185 (95% CI 1.63-6.19, p = .0006). The combination also correlated with lower HOMA-IR (diff −0.532, p = 0.003), higher resting metabolic rate (diff ~102 kcal/day, p = 0.038), and decreased all-cause mortality (HR 0.72) over six years of follow-up.

The critical contextual finding comes from Mammarella et al. 2000⁵⁵ Mammarella et al. 2000
Mammarella S et al. Interaction between the G1057D variant of IRS-2 and overweight in the pathogenesis of type 2 diabetes. Hum Mol Genet. 2000. In Italian subjects without overweight, the Asp allele dose-dependently protected against type 2 diabetes (DD genotype OR 0.18, 95% CI 0.04-0.68; p for trend = .0012). But in overweight subjects, the same genotype reversed to dramatically increase diabetes risk (DD OR 5.74, 95% CI 1.11-29.78; p for trend = .0047). This genotype-environment interaction is one of the most dramatic in the IIS literature and fundamentally shapes how to interpret your results.

Practical Implications

The Asp variant's longevity benefit appears to operate through subtly reduced IIS flux in the lean state, where higher insulin sensitivity reduces the chronic mTOR activation that accelerates cellular aging. Maintaining normal body weight is therefore the primary intervention for Asp allele carriers — not because weight management is generic health advice, but because this specific variant's protective effect mechanistically depends on metabolic context. Overweight Asp/Asp carriers face a compound risk: their attenuated IRS2 signaling, combined with the chronic hyperinsulinemia of obesity, creates insulin resistance rather than insulin sensitivity.

Monitoring fasting insulin and HOMA-IR (calculated from fasting glucose and insulin) provides a direct readout of whether your IRS2 variant is functioning in its protective mode or reverting to its insulin-resistant mode. Asp/Asp individuals in their 60s and beyond should also monitor for signs of cardiac metabolic risk, as one study found higher epicardial fat thickness in elderly Asp carriers, independent of body weight.

Interactions

The strongest documented interaction is the IGF1R-IRS2-UCP2 triple combination. IGF1R rs2229765 sits directly upstream of IRS2 in the signaling cascade; when both genes carry their longevity variants, the combined attenuation of IIS flux is amplified beyond either variant alone. UCP2 rs659366 (Val allele) modulates mitochondrial uncoupling downstream of the pathway, adding a third layer of IIS attenuation. The OR of 3.185 for the triple combination versus ~2.0 for IRS2 alone quantifies this synergy.

The IIS pathway also intersects with neurodegeneration: reduced IRS2 signaling protects against tau hyperphosphorylation and amyloid accumulation in animal models of Alzheimer's disease. Human brains with Alzheimer's disease show specifically reduced IRS2 levels in affected neurons. Whether the Gly1057Asp variant modifies dementia risk in humans has not been directly tested.