Mechanisms of albumin uptake by proximal tubular cells.
The likely role of albumin in the induction tubulo-interstitial injury in proteinuria has stimulated considerable interest in the entry of albumin into the proximal tubule and its subsequent uptake by proximal tubular cells. Currently, there is considerable controversy over the degree of glomerular permeability to albumin. After filtration, however, albumin binds to megalin and cubulin, two giant receptors in the apical membrane of proximal tubular cells. Albumin is subsequently re-absorbed by proximal tubular cells by receptor-mediated endocytosis, a process subject to complex regulation. The interaction of albumin with proximal tubule cells also leads to the generation of intracellular signals. The understanding of these pathways may provide important insights into the pathogenesis of renal scarring in proteinuria.
Brunskill
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Departments of Cell Physiology and Pharmacology and Nephrology, University of Leicester, Faculty of Medicine and Biological Sciences, Leicester, UK. njb18@le.ac.uk
D000418:Albumins / Q000378:metabolism / Q000493:pharmacokinetics*; D000419:Albuminuria / Q000150:complications; D000818:Animals; D002460:Cell Line; D018450:Disease Progression; D004847:Epithelial Cells / Q000378:metabolism; D026541:Heymann Nephritis Antigenic Complex; D006801:Humans; D007674:Kidney Diseases / Q000209:etiology / Q000378:metabolism; D007678:Kidney Glomerulus / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D011485:Protein Binding
D000418:Albumins; D026541:Heymann Nephritis Antigenic Complex; D008562:Membrane Glycoproteins