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Quantification of Different Transferrin Receptor Pools in Primary Cultures of Porcine Blood‐Brain Barrier Endothelial Cells
Author(s) -
Van Gelder W.,
HuijskesHeins M. I. E.,
Van Dijk J. P.,
CletonSoeteman M. I.,
Van Eijk H. G.
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.64062708.x
Subject(s) - transferrin receptor , transferrin , receptor , blood–brain barrier , intracellular , endocytic cycle , biology , microbiology and biotechnology , cell , cell surface receptor , chemistry , biochemistry , central nervous system , endocytosis , endocrinology
Distribution of iron in the brain varies with region, cell type, and age. Furthermore, some neurological diseases are accompanied by an abnormal accumulation of iron in specific areas of the CNS. These findings implicate a mobile intracerebral iron pool; however, transport of iron across the blood‐brain barrier and its regulation are largely unknown. In an extensive series of experiments in primary cultures of porcine blood‐brain barrier endothelial cells, we separately quantified surface‐bound and total cellular transferrin receptor pools. Although 90% of all transferrin receptors were located inside the cell, only 10% of these intracellular receptors actively took part in the endocytic cycle. This large “inactive” intracellular transferrin receptor pool could either function as a storage site for spare receptors or be activated by the cell to increase its capacity for iron transport. Data were corrected for nonspecific binding by a separate biochemical assessment using a 100‐fold excess of unlabeled ligand. Data were also analyzed in a nonlinear curve‐fit program. This resulted in a less elaborate and less biased estimate of nonspecific binding.