<i>ist-1/IRS1</i> affects L1 starvation resistance in <i>daf-16/FoxO-</i> dependent and independent fashion.

Abstract

The mammalian IRS1 gene is an important adaptor for the insulin and insulin-like growth factor receptors, but its sole homolog in the nematode C. elegans , ist-1 , has received relatively little attention. We show that ist-1 /IRS1 has modest effects on L1 starvation resistance, with two null mutants increasing larval growth and reproduction after recovery from extended L1 arrest. ist-1 /IRS1 mutants increase nuclear localization of DAF-16 /FoxO, a critical effector of insulin/IGF signaling, in starved L1 larvae, consistent with IST-1 /IRS1 transducing DAF-2 /IGFR signaling. However, epistasis analysis suggests that ist-1 /IRS1 also functions independently of daf-16 /FoxO , suggesting additional, novel function.