Figure 1g11

Ischemia upregulates endoplasmic reticulum (ER) molecular chaperones. Molecular chaperones of the ER are believed to function normally to prevent inappropriate intra- or intermolecular interactions during the folding and assembly of proteins [20, 54]. However, ER molecular chaperones are also part of the "quality control" apparatus involved in the recognition, retention, and degradation of proteins that fail to fold or assemble properly as they transit the ER [20, 54]. In fact, the messages encoding the ER molecular chaperones are known to increase in response to intraorganelle accumulation of such malfolded proteins [11, 20, 54, 55]. Here, Northern blot analysis of total RNA from either whole kidney or cultured epithelial cells demonstrates that ischemia or ATP depletion induces the mRNAs that encode the ER molecular chaperones, including immunoglobulin binding protein (BiP), 94 kDa glucose regulated protein (grp94), and 72 kDa endoplasmic reticulum protein (Erp72) [11]. This suggests not only that ischemia or ATP depletion causes the accumulation of mal-folded proteins in the ER but that a major effect of ischemia and ATP depletion could be perturbation of the "folding environment" of the ER and disruption of protein processing. GAPDH—glyceraldehyde-3-phosphate dehydrogenase; Hsp70—70 kDa heat-shock protein. (From Kuznetsov et al. [11]; with permission.)

Antimycin A

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