Required for TORC1 to properly control gene expression and chronological life span. Plays an essential role in initiation of the G0 program by preventing the degradation of specific nutrient-regulated mRNAs via the 5'-3' mRNA decay pathway. Interacts with RIM15, DHH1, PBP1, PBP4 AND LSM12. Phosphorylated at Ser-64 by RIM15. Belongs to the endosulfine family.