NA+/K+-ATPASE STABILIZATION BY Hsp70 IN OUTER STRIPE OF OUTER MEDULLA DURING RECOVERY FROM LOW PROTEIN DIET IN RATS

CELESTE RUETE; LILIANA CARRIZO; PATRICIA GARRAMUÑO VALLÉS

Cell Stress and Chaperones

Cell Stress Society International Churchill Livingstone

Lugar: New York- United States; Año: 2008 p. 157 - 167

1466-1268

Low protein diet induces injury from energy depletion in renal epithelial cells. Overexpression of heat shock proteins has been implicated in the restoration of the cytoskeletal anchorage of Na+K+ATPase. We tested whether Hsp70 would stabilize renal Na+K+ATPase attachment to the cytoskeleton from cortex and outer stripe of outer medulla (OSOM) during recovery from LP feeding. Rats were fed with a LP diet (8% protein) for 14 days, then the animals were recovered with 24% protein diet (RP), control group received 24% protein diet (NP). Increased Na+K+ATPase dissociation was demonstrated in soluble fraction from OSOM as a result of LP diet vs NP. Meanwhile, decreased Hsp70 levels in the same fraction were shown. Translocation of Hsp70 to the cytoskeletal injured fraction associated with stabilization of Na+K+ATPase was shown in OSOM from LP after in vitro coincubation of the cytoskeletal fraction of LP and non cytoskeletal fraction of RP. These effects were abolished by the addition of anti-Hsp70 antibody. Coimmunoprecipitation showed that the amount of Na+K+ATPase coprecipitating with Hsp70 increased in OSOM from LP. In LP and RP cortex tissues, interaction of both proteins was similar to control. Our results allow us to suggest that Hsp70 has a critical protective role in the integrity of the cytoskeletal anchorage of Na+K+ATPase during recovery from ATP depleted injury in OSOM from LP.