Joan D. Ferraris

Learn More
Cells in the renal inner medulla are normally exposed to extraordinarily high levels of NaCl and urea. The osmotic stress causes numerous perturbations because of the hypertonic effect of high NaCl and the direct denaturation of cellular macromolecules by high urea. High NaCl and urea elevate reactive oxygen species, cause cytoskeletal rearrangement,(More)
Cells of almost all organisms accumulate organic osmolytes when exposed to hyperosmolality, most often in the form of high salt or urea. In this review, we discuss 1) how the organic osmolytes protect; 2) the identity of osmolytes in Archaea, bacteria, yeast, plants, marine animals, and mammals; 3) the mechanisms by which they are accumulated; 4) sensors of(More)
High NaCl activates the transcription factor tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP), resulting in increased transcription of several protective genes, including the glycine betaine/gamma-aminobutyric acid transporter (BGT1). High NaCl damages DNA, and DNA damage activates ataxia telangiectasia mutated (ATM)(More)
  • C L Chou, K P Yip, +4 authors M A Knepper
  • The Journal of biological chemistry
  • 2000
In the renal collecting duct, vasopressin increases osmotic water permeability (P(f)) by triggering trafficking of aquaporin-2 vesicles to the apical plasma membrane. We investigated the role of vasopressin-induced intracellular Ca(2+) mobilization in this process. In isolated inner medullary collecting ducts (IMCDs), vasopressin (0.1 nm) and(More)
Hypertonicity-induced binding of the transcription factor TonEBP/OREBP to its cognate DNA element, ORE/TonE, is associated with increased transcription of several osmotically regulated genes. Previously, it was found that hypertonicity rapidly causes nuclear translocation and phosphorylation of TonEBP/OREBP and, more slowly, increases TonEBP/OREBP(More)
Tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP) is a Rel protein that activates transcription of osmoprotective genes at high extracellular NaCl. Other Rel proteins NFAT1-4 and NF-kappaB complex with activator protein-1 (AP-1) to transactivate target genes through interaction at composite NFAT/NF-kappaB.AP-1 sites.(More)
UNLABELLED Hypertonicity-induced increase in activity of the transcription factor tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP) protects renal cells by increasing transcription of genes, including those involved in increased accumulation of organic osmolytes. We previously showed that hypertonicity increases(More)
Organisms, almost universally, adapt to hyperosmotic stress through increased accumulation of organic osmolytes but the molecular mechanisms have only begun to be addressed. Among mammalian tissues, renal medullary cells are uniquely exposed to extreme hyperosmotic stress. Sorbitol, synthesized through aldose reductase, is a predominant osmolyte induced(More)
Elevated temperature rapidly increases expression of genes for heat shock proteins (HSP), including HSP-70. The response is presumably triggered by denaturation of cell proteins and helps in their renaturation. Hypertonicity may also denature proteins, but the protective response, which is accumulation of compatible organic osmolytes [including betaine and(More)
Hypertonicity increases mRNA and protein abundance of the transcription factor tonicity-responsive enhancer/osmotic response element binding protein (TonEBP/OREBP), contributing to increased transcription of downstream osmoprotective genes. Previously, this was attributed to increased transcription of TonEBP/OREBP because no change was found in its mRNA(More)