An induced extracellular matrix protein reverses the polarity of band 3 in intercalated epithelial cells

Cell. 1994 Mar 25;76(6):1053-61. doi: 10.1016/0092-8674(94)90382-4.


The intercalated epithelial cell exists in two interconvertible forms in vivo, 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 endocytosis. But when the cells were plated at high density, band 3 was basolateral, and there was vigorous apical endocytosis. Extracellular matrix produced by high density cells was able to retarget band 3 in low density cells and to induce apical endocytosis, as did a 230 kd protein partially purified from this matrix. Therefore, polarized targeting of some proteins is determined by external cues that might determine their polarity by reorganizing the cytoplasm.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Anion Exchange Protein 1, Erythrocyte / physiology*
  • Antiporters / physiology*
  • Cell Count
  • Cell Polarity / physiology*
  • Chloride-Bicarbonate Antiporters
  • Clone Cells
  • Endocytosis / physiology
  • Epithelial Cells
  • Epithelium / metabolism
  • Extracellular Matrix Proteins / physiology*
  • Kidney Tubules, Collecting / cytology
  • Rabbits


  • Anion Exchange Protein 1, Erythrocyte
  • Antiporters
  • Chloride-Bicarbonate Antiporters
  • Extracellular Matrix Proteins