The molecular interactions between filtered proteins and proximal tubular cells in proteinuria.

The Molecular Interactions Between Filtered Proteins and Proximal Tubular Cells in Proteinuria Richard

NHE3 Na+/H+ exchanger supports proximal tubular protein reabsorption in vivo.

Proximal tubular receptor-mediated endocytosis (RME) of filtered proteins prevents proteinuria. Pharmacological and genetic studies in cultured opossum kidney cells have shown that the apical Na(+)/H(+) exchanger isoform 3 (NHE3) supports RME by interference with endosomal pH homeostasis and endocytic fusion events. However, it is not known whether NHE3 also supports proximal tubular RME in viv...

Proteinuria as a determinant of renal expression of heme oxygenase-1: studies in models of glomerular and tubular proteinuria in the rat.

Heme oxygenase-1 (HO-1), a cytoprotective gene, is commonly induced in renal tubules in the diseased kidney. Because proteinuria is a hallmark for kidney disease, we examined the relationship between proteinuria and tubular induction of HO-1, specifically questioning whether increased trafficking of protein across the renal tubular epithelium, as a consequence of proteinuria, induces tubular ex...

Renal phenotypic investigations of megalin-deficient patients: novel insights into tubular proteinuria and albumin filtration.

BACKGROUND The reabsorption of filtered plasma proteins, hormones and vitamins by the renal proximal tubules is vital for body homeostasis. Studies of megalin-deficient mice suggest that the large multi-ligand endocytic receptor megalin plays an essential role in this process. In humans, dysfunctional megalin causes the extremely rare Donnai-Barrow/Facio-Oculo-Acustico-Renal (DB/FOAR) syndrome ...

Limited capacity of proximal tubular proteolysis in mice with proteinuria.

Albuminuria is associated with the additional loss in the urine of small molecular weight proteins normally degraded by the proximal convoluted tubule (PCT), and competition for binding to the megalin/cubilin reuptake system has been considered the likely cause. We have previously reported that deficiency of the intrinsic lysosomal protein Limp-2 causes tubular proteinuria due to reduced fusion...