Work

Developmental and conditional regulation of DAF-2/INSR ubiquitination in Caenorhabditis elegans

Year: 2025

Type: article

Abstract: ABSTRACT Insulin/IGF signaling (IIS) regulates developmental and metabolic plasticity. Conditional regulation of insulin-like peptide expression and secretion promotes different phenotypes in different environments. However, IIS can also be regulated by other, less-understood mechanisms. For example, stability of the only known insulin/IGF receptor in C. elegans , DAF-2/INSR, is regulated by CHIP-dependent ubiquitination. Disruption of chn-1/CHIP reduces longevity in C. elegans by increasing DAF-2/INSR abundance and IIS activity in adults. Likewise, mutation of a ubiquitination site causes daf-2(gk390525) to display gain-of-function phenotypes in adults. However, we show that this allele displays loss-of-function phenotypes in larvae, and that its effect on IIS activity transitions from negative to positive during development. In contrast, the allele acts like a gain-of-function in larvae cultured at high temperature, inhibiting temperature-dependent dauer formation. Disruption of chn-1/CHIP causes an increase in IIS activity in starved L1 larvae, unlike daf-2(gk390525) . CHN-1/CHIP ubiquitinates DAF-2/INSR at multiple sites. These results suggest that the sites that are functionally relevant to negative regulation of IIS vary in larvae and adults, at different temperatures, and in nutrient-dependent fashion, revealing additional layers of IIS regulation. ARTICLE SUMMARY Insulin-like signaling plays a critical role in helping animals adapt to different environmental conditions. Differences in abundance of insulin molecules drive differences in insulin signaling, affecting growth, metabolism, and resistance to stressful conditions. Previous work in the roundworm C. elegans showed that targeted degradation of the insulin receptor also regulates insulin signaling. We show here that this process is affected by developmental stage, nutrient availability, and temperature, revealing additional ways that insulin-like signaling is regulated in this valuable animal model.

Source: G3 Genes Genomes Genetics

Authors: Ivan B Falsztyn, Seth M Taylor, L Ryan Baugh

Institution: Duke University

Language: English

Topic: Genetics, Aging, and Longevity in Model Organisms

Subfield: Aging

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: gold

Estimated APC paid: $2,709

Funders: National Institutes of Health, National Institute of General Medical Sciences, Office of Research Infrastructure Programs, National Institutes of Health

Awards: G1994913649, Systemic, maternal and transgenerational effects of nutrient stress, Genetic and Genomic Analysis of Starvation Resistance in C. elegans, G9000028377, Caenorhabditis Genetics Center