ID   RET4_XENLA              Reviewed;         197 AA.
AC   P06172;
DT   01-JAN-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1988, sequence version 1.
DT   03-AUG-2022, entry version 99.
DE   RecName: Full=Retinol-binding protein 4;
DE   AltName: Full=Plasma retinol-binding protein;
DE            Short=PRBP;
DE   Flags: Precursor;
GN   Name=rbp4;
OS   Xenopus laevis (African clawed frog).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Amphibia;
OC   Batrachia; Anura; Pipoidea; Pipidae; Xenopodinae; Xenopus; Xenopus.
OX   NCBI_TaxID=8355;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=3558378; DOI=10.1016/s0021-9258(18)61134-2;
RA   McKearin D.M., Barton M.C., Keller M.J., Shapiro D.J.;
RT   "Estrogen induces transcription of the Xenopus laevis serum retinol-binding
RT   protein gene.";
RL   J. Biol. Chem. 262:4939-4942(1987).
CC   -!- FUNCTION: Retinol-binding protein that mediates retinol transport in
CC       blood plasma. Delivers retinol from the liver stores to the peripheral
CC       tissues. Transfers the bound all-trans retinol to STRA6, that then
CC       facilitates retinol transport across the cell membrane.
CC       {ECO:0000250|UniProtKB:P02753}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:P04916}.
CC   -!- SIMILARITY: Belongs to the calycin superfamily. Lipocalin family.
CC       {ECO:0000305}.
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DR   EMBL; J02718; AAA20483.1; -; mRNA.
DR   PIR; A30013; A30013.
DR   AlphaFoldDB; P06172; -.
DR   SMR; P06172; -.
DR   PRIDE; P06172; -.
DR   Proteomes; UP000186698; Genome assembly.
DR   GO; GO:0005615; C:extracellular space; ISS:UniProtKB.
DR   GO; GO:0016918; F:retinal binding; IEA:UniProtKB-KW.
DR   GO; GO:0019841; F:retinol binding; IEA:UniProtKB-KW.
DR   GO; GO:0034632; F:retinol transmembrane transporter activity; IEA:InterPro.
DR   Gene3D; 2.40.128.20; -; 1.
DR   InterPro; IPR012674; Calycin.
DR   InterPro; IPR022271; Lipocalin_ApoD.
DR   InterPro; IPR022272; Lipocalin_CS.
DR   InterPro; IPR000566; Lipocln_cytosolic_FA-bd_dom.
DR   InterPro; IPR002449; Retinol-bd/Purpurin.
DR   PANTHER; PTHR11873; PTHR11873; 1.
DR   Pfam; PF00061; Lipocalin; 1.
DR   PIRSF; PIRSF036893; Lipocalin_ApoD; 1.
DR   PIRSF; PIRSF500204; RBP_purpurin; 1.
DR   PRINTS; PR01174; RETINOLBNDNG.
DR   SUPFAM; SSF50814; SSF50814; 1.
DR   PROSITE; PS00213; LIPOCALIN; 1.
PE   2: Evidence at transcript level;
KW   Disulfide bond; Reference proteome; Retinol-binding; Secreted; Signal;
KW   Transport; Vitamin A.
FT   SIGNAL          1..20
FT                   /evidence="ECO:0000255"
FT   CHAIN           21..197
FT                   /note="Retinol-binding protein 4"
FT                   /id="PRO_0000017972"
FT   BINDING         118
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250|UniProtKB:P27485"
FT   DISULFID        24..180
FT                   /evidence="ECO:0000250|UniProtKB:P02753"
FT   DISULFID        90..194
FT                   /evidence="ECO:0000250|UniProtKB:P02753"
FT   DISULFID        140..149
FT                   /evidence="ECO:0000250|UniProtKB:P02753"
SQ   SEQUENCE   197 AA;  22655 MW;  6A94ED37497FE72D CRC64;
     MERKVLGLLI ALGFLGSCLA EKNCRVDNFE VMKDFNKERY AGVWYAVAKK DPEGLFLLDN
     IAANFKIEDN GKTTATAKGR VRILDKLELC ANMVGTFIET NDPAKYRMKY HGALAILERG
     LDDHWVVDTD YTTYAITYAC RRRNLDGTCR DSYSFVFSRD INGLPSESQR IVRRRQEQLC
     LDRKYRVVVH NGYCETN