Tissue-specific sorting of the human LDL receptor in polarized epithelia of transgenic mice

Ravindra K. Pathak, Masayuki Yokode, Robert E Hammer, Sandra L Hofmann, Michael S Brown, Joseph L Goldstein, Richard G W Anderson

Research output: Contribution to journalArticlepeer-review

71 Scopus citations

Abstract

The distribution of human low density lipoprotein (LDL) receptors was studied by immunofluorescence and immunoelectron microscopy in epithelial cells of transgenic mice that express high levels of receptors under control of the metallothionein-I promoter. In hepatocytes and intestinal epithelial cells, the receptors were confined to the basal and basolateral surfaces, respectively. Very few LDL receptors were present in coated pits or intracellular vesicles. In striking contrast, in the epithelium of the renal tubule the receptors were present on the apical (lumenal) surface where they appeared to be concentrated at the base of microvilli and were abundant in vesicles of the endocytic recycling pathway. Intravenously administered LDL colloidal gold conjugates bound to the receptors on hepatocyte microvilli and were slowly internalized, apparently through slow migration into coated pits. We conclude that (a) sorting of LDL receptors to the surface of different epithelial cells varies with each tissue; and (b) in addition to a signal for clustering in coated pits, the LDL receptor may contain a signal for retention in noncoated membrane that is manifest in hepatocytes and intestinal epithelial cells, but not in renal epithelial cells or cultured human fibroblasts.

Original languageEnglish (US)
Pages (from-to)347-359
Number of pages13
JournalJournal of Cell Biology
Volume111
Issue number2
DOIs
StatePublished - Aug 1990

ASJC Scopus subject areas

  • Cell Biology

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