ID   PIGR_CAPHI              Reviewed;          14 AA.
AC   P85296;
DT   23-OCT-2007, integrated into UniProtKB/Swiss-Prot.
DT   23-OCT-2007, sequence version 1.
DT   07-OCT-2020, entry version 26.
DE   RecName: Full=Polymeric immunoglobulin receptor;
DE            Short=PIgR;
DE            Short=Poly-Ig receptor;
DE   Contains:
DE     RecName: Full=Secretory component;
DE   Flags: Fragment;
GN   Name=PIGR {ECO:0000250|UniProtKB:P01833};
OS   Capra hircus (Goat).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Artiodactyla; Ruminantia; Pecora; Bovidae;
OC   Caprinae; Capra.
OX   NCBI_TaxID=9925;
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE.
RA   Koenig S., Mehlich A.M., Ackermann D.;
RT   "Access to lower abundant bovine and caprine whey proteins: the impact of
RT   caseins and lactoglobulin on proteome analysis.";
RL   Anal. Bioanal. Chem. 0:0-0(2007).
CC   -!- FUNCTION: Mediates selective transcytosis of polymeric IgA and IgM
CC       across mucosal epithelial cells. Binds polymeric IgA and IgM at the
CC       basolateral surface of epithelial cells. The complex is then
CC       transported across the cell to be secreted at the apical surface.
CC       During this process, a cleavage occurs that separates the extracellular
CC       (known as the secretory component) from the transmembrane segment (By
CC       similarity). Through its N-linked glycans ensures anchoring of
CC       secretory IgA (sIgA) molecules to mucus lining the epithelial surface
CC       to neutralize extracellular pathogens. On its own (free form) may act
CC       as a non-specific microbial scavenger to prevent pathogen interaction
CC       with epithelial cells (By similarity). {ECO:0000250|UniProtKB:P01833}.
CC   -!- SUBUNIT: Interacts (mainly via CDR1-like domain) with dimeric IgA.
CC       Interacts (mainly via CDR2-like domain) with pentameric IgM (By
CC       similarity). Either free or part of the secretory IgA (sIgA) complex
CC       that consists of two, four or five IgA monomers, and two additional
CC       non-Ig polypeptides, namely the JCHAIN and the secretory component (the
CC       proteolytic product of PIGR). Free secretory component interacts with
CC       bacterial antigens toxA of C. difficile and eae of E. coli (By
CC       similarity). {ECO:0000250|UniProtKB:P01833}.
CC   -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000250|UniProtKB:P01833};
CC       Single-pass type I membrane protein {ECO:0000255}. Secreted
CC       {ECO:0000250|UniProtKB:P01833}.
CC   -!- PTM: N-glycosylated. N-glycosylation is required for anchoring IgA
CC       molecules to mucus, but is not necessary for Ig binding.
CC       {ECO:0000250|UniProtKB:P01833}.
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DR   Proteomes; UP000291000; Unassembled WGS sequence.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
PE   1: Evidence at protein level;
KW   Cell membrane; Direct protein sequencing; Immunoglobulin domain; Membrane;
KW   Reference proteome; Repeat; Secreted; Transmembrane.
FT   CHAIN           <1..>14
FT                   /note="Polymeric immunoglobulin receptor"
FT                   /id="PRO_0000308185"
FT   CHAIN           <1..>14
FT                   /note="Secretory component"
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000308186"
FT   DOMAIN          <1..>14
FT                   /note="Ig-like V-type"
FT   NON_TER         1
FT   NON_TER         14
SQ   SEQUENCE   14 AA;  1515 MW;  CA40FE538B17A642 CRC64;
     YGETAAVYVA VESR