IgG receptor FcRn large subunit p51 (FcRn) (IgG Fc fragment receptor transporter alpha chain) (Neonatal Fc receptor)
1_MGVPR 6_ PQPWA 11_ LGLLL 16_ FLLPG 21_ SLGAE 26_ SHLSL 31_ LYHLT 36_ AVSSP 41_ APGTP 46_ AFWVS 51_ GWLGP 56_ QQYLS 61_ YNSLR 66_ GEAEP 71_ CGAWV 76_ WENQV 81_ SWYWE 86_ KETTD 91_ LRIKE 96_ KLFLE 101_ AFKAL 106_ GGKGP 111_ YTLQG 116_ LLGCE 121_ LGPDN 126_ TSVPT 131_ AKFAL 136_ NGEEF 141_ MNFDL 146_ KQGTW 151_ GGDWP 156_ EALAI 161_ SQRWQ 166_ QQDKA 171_ ANKEL 176_ TFLLF 181_ SCPHR 186_ LREHL 191_ ERGRG 196_ NLEWK 201_ EPPSM 206_ RLKAR 211_ PSSPG 216_ FSVLT 221_ CSAFS 226_ FYPPE 231_ LQLRF 236_ LRNGL 241_ AAGTG 246_ QGDFG 251_ PNSDG 256_ SFHAS 261_ SSLTV 266_ KSGDE 271_ HHYCC 276_ IVQHA 281_ GLAQP 286_ LRVEL 291_ ESPAK 296_ SSVLV 301_ VGIVI 306_ GVLLL 311_ TAAAV 316_ GGALL 321_ WRRMR 326_ SGLPA 331_ PWISL 336_ RGDDT 341_ GVLLP 346_ TPGEA 351_ QDADL 356_KDVNV
1: Cell surface receptor that transfers passive humoral immunity from the mother to the newborn. Binds to the Fc region of monomeric immunoglobulin gamma and mediates its selective uptake from milk (PubMed:10933786, PubMed:7964511). IgG in the milk is bound at the apical surface of the intestinal epithelium. The resultant FcRn-IgG complexes are transcytosed across the intestinal epithelium and IgG is released from FcRn into blood or tissue fluids. Throughout life, contributes to effective humoral immunity by recycling IgG and extending its half-life in the circulation. Mechanistically, monomeric IgG binding to FcRn in acidic endosomes of endothelial and hematopoietic cells recycles IgG to the cell surface where it is released into the circulation (PubMed:10998088). In addition of IgG, regulates homeostasis of the other most abundant circulating protein albumin/ALB (PubMed:24469444, PubMed:28330995)
2: (Microbial infection) Acts as an uncoating receptor for a panel of echoviruses including Echovirus 5, 6, 7, 9, 11, 13, 25 and 29