Tissue-specific sorting of the human LDL receptor in polarized epithelia of transgenic mice.
J Cell Biol
; 111(2): 347-59, 1990 Aug.
Article
en En
| MEDLINE
| ID: mdl-2199454
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.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores de LDL
Tipo de estudio:
Prognostic_studies
Aspecto:
Determinantes_sociais_saude
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Cell Biol
Año:
1990
Tipo del documento:
Article