The redox state of the cell is involved in the regulation of many physiological functions as well as in thepathogenesis of several diseases, and is strictly dependent on the amount of iron in its catalytically active state.Alterations of iron homeostasis determine increased steady-state concentrations of Reactive Oxygen Species(ROS) that cause lipid peroxidation, DNA damage and altered protein folding. Ferritin keeps the intracellulariron in a non-toxic and readily available form and consequently plays a central role in iron and redoxhomeostasis. The protein is composed by 24 subunits of the H- and L-type, coded by two different genes, withstructural and functional differences. The aim of this study was to shed light on the role of the single H ferritinsubunit (FHC) in keeping the native correct protein three-dimensional structure. To this, we performed Ramanspectroscopy on protein extracts from K562 cells subjected to FHC silencing. The results show a significantincrease in the percentage of disordered structures content at a level comparable to that induced by H2O2treatment in control cells. ROS inhibitor and iron chelator were able to revert protein misfolding. This integratedapproach, involving Raman spectroscopy and targeted-gene silencing, indicates that an imbalance of the heavyto-light chain ratio in the ferritin composition is able to induce severe but still reversible modifications in proteinfolding and uncovers new potential pathogenetic mechanisms associated to intracellular iron perturbation.
H ferritin silencing induces protein misfolding in K562 cells: A Raman analysis
Fabiana Zolea;Flavia Biamonte;Patrizio Candeloro;Maddalena Di Sanzo;Anna Di Vito;Barbara Quaresima;Nadia Lobello;Francesca Trecroci;Enzo Di Fabrizio;Giovanni Cuda;Costanzo F
2015-01-01
Abstract
The redox state of the cell is involved in the regulation of many physiological functions as well as in thepathogenesis of several diseases, and is strictly dependent on the amount of iron in its catalytically active state.Alterations of iron homeostasis determine increased steady-state concentrations of Reactive Oxygen Species(ROS) that cause lipid peroxidation, DNA damage and altered protein folding. Ferritin keeps the intracellulariron in a non-toxic and readily available form and consequently plays a central role in iron and redoxhomeostasis. The protein is composed by 24 subunits of the H- and L-type, coded by two different genes, withstructural and functional differences. The aim of this study was to shed light on the role of the single H ferritinsubunit (FHC) in keeping the native correct protein three-dimensional structure. To this, we performed Ramanspectroscopy on protein extracts from K562 cells subjected to FHC silencing. The results show a significantincrease in the percentage of disordered structures content at a level comparable to that induced by H2O2treatment in control cells. ROS inhibitor and iron chelator were able to revert protein misfolding. This integratedapproach, involving Raman spectroscopy and targeted-gene silencing, indicates that an imbalance of the heavyto-light chain ratio in the ferritin composition is able to induce severe but still reversible modifications in proteinfolding and uncovers new potential pathogenetic mechanisms associated to intracellular iron perturbation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.