An induced extracellular matrix protein reverses the polarity of band 3 in intercalated epithelial cells
J van Adelsberg, JC Edwards, J Takito, B Kiss… - Cell, 1994 - cell.com
J van Adelsberg, JC Edwards, J Takito, B Kiss, Q Al-Awqati
Cell, 1994•cell.comThe intercalated epithelial cell exists in two interconvertlble forms in viva, one where band 3
protein is apical and the other where it is basolateral. We seeded an immortalized clone of
these cells at low density and found that band 3 was apical at confluence. There was little or
no apical endocytods. But when the cells were plated at high density, band 3 was
basolateral, and there was vigorous apical endocytosls. Extracellular matrix produced by
high den&y cells was able to retarget band 3 in low density cells and to induce apical …
protein is apical and the other where it is basolateral. We seeded an immortalized clone of
these cells at low density and found that band 3 was apical at confluence. There was little or
no apical endocytods. But when the cells were plated at high density, band 3 was
basolateral, and there was vigorous apical endocytosls. Extracellular matrix produced by
high den&y cells was able to retarget band 3 in low density cells and to induce apical …
Summary
The intercalated epithelial cell exists in two interconvertlble forms in viva, one where band 3 protein is apical and the other where it is basolateral. We seeded an immortalized clone of these cells at low density and found that band 3 was apical at confluence. There was little or no apical endocytods. But when the cells were plated at high density, band 3 was basolateral, and there was vigorous apical endocytosls. Extracellular matrix produced by high den&y cells was able to retarget band 3 in low density cells and to induce apical endocytosis, as did a 230 kd protein partlally purifled from this matrix. Therefore, polarized targeting of some proteins Is determined by external cues that mlght determine their polarity by reorganizing the cytoplasm.
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