WNT2 and hyperinsulinemic hypoglycemia, familial, 4: To confirm the possibility of iron depletion in the J774A.1 cell as mechanism of increased IRE–IRP interaction in LD infection we determined LIP using fluorescence indicator dye calcein-AM, which does not show any fluorescence in iron-sufficient condition but fluorescence level is increased in deficiency (Stäubli and Boelsterli, 1998).