Effect of mutation of amino acids 246–251 (KRKHKK) in HSP72 on protein synthesis and recovery from hypoxic injury
- 1 December 2005
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Heart and Circulatory Physiology
- Vol. 289 (6), H2519-H2525
- https://doi.org/10.1152/ajpheart.00872.2004
Abstract
Heat shock protein (HSP)72, the inducible form of HSP70, protects cells against a variety of injuries, but underlying mechanisms are poorly defined. To investigate the protective effects of HSP72, multiple clones expressing wild-type (WT) HSP72 and two mutants with defective nucleolar and nuclear localization (M45 and 985A, respectively) were made with the tet-off system in C2C12 cells. Four different parameters of cell function/injury were examined after simulated ischemia: protein synthesis, polysome formation, DNA synthesis, and lactate dehydrogenase (LDH release). Overexpression of WT HSP72 was also compared to nontransfected C2C12 cells. As expected, overexpression of HSP72 protected against simulated ischemia and reoxygenation for all parameters. In contrast, both M45 and 985A showed abnormal protein synthesis and polysome formation, both after simulated ischemia and under control conditions. Total RNA was slightly reduced in M45 and 985A at baseline, but 1 h after hypoxia, RNA levels were protected in all clones but significantly decreased in nontransfected C2C12 cells. Clones expressing 985A had nuclear retention of mRNA, suggesting that HSP72 is needed for nuclear export of RNA. All clones, both WT and mutant, had protection of DNA synthesis compared to C2C12 cells, but 985A had greater release of LDH after injury than any other group. These results support a multifactoral protective effect of HSP72, some aspects dependent on nuclear localization with stress and some not. The protection of protein synthesis and polysome formation, and abnormalities in these with the mutants, support a role for HSP72 in these processes both in the normal cell and in injury.Keywords
This publication has 22 references indexed in Scilit:
- HSP70 Interacts with Ribosomal Subunits of Thermotolerant CellsShock, 2003
- Translation Initiation Control by Heme-Regulated Eukaryotic Initiation Factor 2α Kinase in Erythroid Cells under Cytoplasmic StressesMolecular and Cellular Biology, 2001
- Killing tumour cells by alkylphosphocholines: Evidence for involvement of CD95European Journal of Cell Biology, 2001
- Cytoprotective Mechanism of Heat Shock Protein 70 against Hypoxia/Reoxygenation InjuryJournal of Molecular and Cellular Cardiology, 2000
- Mutation of Amino Acids 246-251 Alters Nuclear Accumulation of Human Heat Shock Protein (HSP) 72 with Stress, But Does Not Reduce ViabilityJournal of Molecular and Cellular Cardiology, 1999
- Differential Expression of Heat Shock Proteins in Normal and Failing Human HeartsJournal of Molecular and Cellular Cardiology, 1998
- Protection against myocardial dysfunction after a brief ischemic period in transgenic mice expressing inducible heat shock protein 70.JCI Insight, 1998
- Transgenic mice expressing the human heat shock protein 70 have improved post-ischemic myocardial recovery.JCI Insight, 1995
- Late preconditioning against myocardial stunning. An endogenous protective mechanism that confers resistance to postischemic dysfunction 24 h after brief ischemia in conscious pigs.JCI Insight, 1995
- Interaction of Hsp 70 with Newly Synthesized Proteins: Implications for Protein Folding and AssemblyScience, 1990