Heme-binding protein HRG-1 is induced by insulin-like growth factor I and associates with the vacuolar H+-ATPase to control endosomal pH and receptor trafficking.
O'Callaghan KM, Ayllon V, O'Keeffe J, Wang Y, Cox OT, Loughran G, Forgac M, O'Connor R. J Biol Chem. 2010 Jan 1; 285(1):381-91. Epub 2009 Oct 29.