title: The intracellular localization and association of porcine Ia-associated invariant chain with the MHC class I-related porcine neonatal Fc receptor for IgG.
abstract: The neonatal Fc receptor (FcRn) transports IgG from mother to young and is involved in antigen presentation. FcRn is structurally similar to MHC class I, but its intracellular trafficking pathway is much more analogous to that of MHC class II. Ia-associated invariant chain (Ii) molecules play an additional role in directing MHC class II trafficking within the endocytic compartments by physical association with MHC class II. This study addresses the question of whether pig Ii chain plays this important role in FcRn trafficking to the endoplasmic reticulum. Red or green fluorescent protein-fused Ii or FcRn was constructed, and the intracellular localization of pig Ii with FcRn was detected using confocal microscopy. Immunoprecipitation and western blotting were used to test for their association. The results indicate that pig Ii chain specifically interacts with both FcRn H chain alone and FcRn-β2m complex, and the CLIP in Ii was required for FcRn-Ii association. A truncated FcRn deletion in the cytoplasmic tail changed the intracellular localization of FcRn. However, the truncated FcRn can still combine Ii. This indicated that the cytoplasmic tail of FcRn fails to affect FcRn association with Ii. These results suggest that association of FcRn with Ii chain is relevant, and appreciation of this process is important to the understanding of how IgG is transported.
authors.affiliation: College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Electronic address: xufazhi1103@sina.com.
authors.forename: Fazhi
authors.initials: F
authors.lastname: Xu
authors.affiliation: AnHui Academy of Medical Sciences, Hefei 230061, China. Electronic address: yehong@163.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Ye
authors.affiliation: College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Electronic address: liuxl@sina.com.
authors.forename: Xuelan
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Electronic address: chenff@163.com.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Chen
authors.affiliation: College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Electronic address: dingxiaoling@163.com.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Ding
authors.affiliation: College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Electronic address: cxy@163.com.
authors.forename: Xingyong
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China. Electronic address: llm@sina.com.
authors.forename: Lvmu
authors.initials: L
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D007074:Immunoglobulin G / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D011961:Receptors, Fc / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D013552:Swine
chemical_list: D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G; D011961:Receptors, Fc; C100688:Fc receptor, neonatal
keywords: FcRn; Ia-associated invariant chain; IgG; Intracellular localization; Pig