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Lateral diffusion of the secretory component (SC) in the basolateral membrane of the human colon carcinoma cell line HT29 assessed with fluorescence recovery after photobleaching
Author(s) -
Gustafsson Mikael,
Sundqvist Tommy,
Magnusson KarlEric
Publication year - 1988
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041370332
Subject(s) - fluorescence recovery after photobleaching , photobleaching , cell culture , fluorescence , chemistry , biophysics , cell , membrane , microbiology and biotechnology , line (geometry) , diffusion , component (thermodynamics) , biology , biochemistry , optics , physics , genetics , geometry , mathematics , thermodynamics
The lateral diffusion of the secretory component (SC), acting as a receptor for dimeric IgA in the basolateral side of intestinal epithelial cells, was studied in the human colonic carcinoma cell line HT29. The HT29 cells were grown in Dulbecco's modified Eagle's medium in which galactose had been substituted for glucose to promote development of small intestine‐like cells, with a distinct separation of the basolateral side from the apical surface. The SC was stained with rhodamine‐labeled polyclonal anti‐human SC rabbit antibodies (Ig) or Fab fragments, and the lateral mobility was assessed with the fluorescence recovery after photobleaching technique. The average lateral diffusion was consistent with a diffusion constant of 7.7 ± 2.0 (mean value ± SD; n = 29) and 7.1 ± 2.3 (n = 30) × 10 −10 cm 2 s −1 for Ig‐and Fab‐labeled receptors, respectively, which is slower than lipid diffusion but is similar to that found for other membrane receptors. The corresponding values for the fraction of mobile receptors were 66 ± 13% and 71 ± 12%, respectively. Cells were labeled from the top of the culture plate, and cells adjacent to a mechanically made rift or a natural opening in the cell monolayer were labeled more strongly, confirming the microscope‐based impression that the basolateral surface primarily harboured the SC receptor.