ATF4 and hyperinsulinemic hypoglycemia, familial, 4: Furthermore, after 8 days of lysine deficiency, an increased expression of other two AA-limitation markers (i.e. atf4 and as) was observed; and also, a decrease in important proteogenic/anabolic pathways’ molecules including members of the IGF system (i.e. pcna, igf-1, igf-2, igf-1rb, akt, erk and 70s6k) [29].