跨细胞
新生儿Fc受体
生物
细胞生物学
受体
细胞质
磷酸化
顶膜
抗体
上皮
免疫球蛋白G
生物化学
免疫学
内吞作用
遗传学
作者
Kevin M. McCarthy,Mark H. C. Lam,Lalitha Subramanian,Reena Shakya,Zezhou Wu,Estelle E. Newton,Neil E. Simister
标识
DOI:10.1242/jcs.114.8.1591
摘要
ABSTRACT The neonatal Fc receptor, FcRn, transports immunoglobulin G (IgG) across intestinal epithelial cells of suckling rats and mice from the lumenal surface to the serosal surface. In cell culture models FcRn transports IgG bidirectionally, but there are differences in the mechanisms of transport in the two directions. We investigated the effects of mutations in the cytoplasmic domain of FcRn on apical to basolateral and basolateral to apical transport of Fc across rat inner medullary collecting duct (IMCD) cells. Basolateral to apical transport did not depend upon determinants in the cytoplasmic domain. In contrast, an essentially tailless FcRn was markedly impaired in apical to basolateral transport. Using truncation and substitution mutants, we identified serine-313 and serine-319 as phosphorylation sites in the cytoplasmic domain of FcRn expressed in Rat1 fibroblasts. Mutations at Ser-319 did not affect transcytosis across IMCD cells. FcRn-S313A was impaired in apical to basolateral transcytosis to the same extent as tailless FcRn, whereas FcRn-S313D transported at wild-type levels. FcRn-S313A recycled more Fc to the apical medium than the wild-type receptor, suggesting that Ser-313 is required to allow FcRn to be diverted from an apical recycling pathway to a transcytotic pathway.
科研通智能强力驱动
Strongly Powered by AbleSci AI