Bidirectional transepithelial IgG transport by a strongly polarized basolateral membrane Fcγ-receptor

SM Claypool, BL Dickinson, JS Wagner… - Molecular biology of …, 2004 - Am Soc Cell Biol
SM Claypool, BL Dickinson, JS Wagner, FE Johansen, N Venu, JA Borawski, WI Lencer…
Molecular biology of the cell, 2004Am Soc Cell Biol
The human MHC class I–related neonatal Fc receptor, hFcRn, mediates bidirectional
transport of IgG across mucosal barriers. Here, we find that at steady state hFcRn distributes
predominantly to an apical intracellular compartment and almost exclusively to the
basolateral cell surface of polarized epithelial cells. It moves only transiently to the apical
membrane. Ligand binding does not redistribute the steady state location of the receptor.
Removal of the cytoplasmic tail that contains di-leucine and tryptophan-based endocytosis …
The human MHC class I–related neonatal Fc receptor, hFcRn, mediates bidirectional transport of IgG across mucosal barriers. Here, we find that at steady state hFcRn distributes predominantly to an apical intracellular compartment and almost exclusively to the basolateral cell surface of polarized epithelial cells. It moves only transiently to the apical membrane. Ligand binding does not redistribute the steady state location of the receptor. Removal of the cytoplasmic tail that contains di-leucine and tryptophan-based endocytosis motifs or incubation at low temperature (18°C) redistributes the receptor apically. The rates of endocytosis of the full-length hFcRn from the apical or basolateral membrane domains, however, are equal. Thus, the strong cell surface polarity displayed by hFcRn results from dominant basolateral sorting by motifs in the cytoplasmic tail that nonetheless allows for a cycle of bidirectional transcytosis.
Am Soc Cell Biol