ID   STAR_HORSE              Reviewed;         285 AA.
AC   O46689;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1998, sequence version 1.
DT   25-MAY-2022, entry version 113.
DE   RecName: Full=Steroidogenic acute regulatory protein, mitochondrial;
DE            Short=StAR;
DE   AltName: Full=START domain-containing protein 1;
DE            Short=StARD1;
DE   Flags: Precursor;
GN   Name=STAR;
OS   Equus caballus (Horse).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Perissodactyla; Equidae; Equus.
OX   NCBI_TaxID=9796;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Follicular cell;
RX   PubMed=9927292; DOI=10.1210/endo.140.2.6499;
RA   Kerban A., Boerboom D., Sirois J.;
RT   "Human chorionic gonadotropin induces an inverse regulation of
RT   steroidogenic acute regulatory protein messenger ribonucleic acid in theca
RT   interna and granulosa cells of equine preovulatory follicles.";
RL   Endocrinology 140:667-674(1999).
CC   -!- FUNCTION: Plays a key role in steroid hormone synthesis by enhancing
CC       the metabolism of cholesterol into pregnenolone. Mediates the transfer
CC       of cholesterol from the outer mitochondrial membrane to the inner
CC       mitochondrial membrane where it is cleaved to pregnenolone (By
CC       similarity). {ECO:0000250|UniProtKB:P49675}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=cholesterol(in) = cholesterol(out); Xref=Rhea:RHEA:39747,
CC         ChEBI:CHEBI:16113; Evidence={ECO:0000250|UniProtKB:P49675};
CC   -!- PATHWAY: Steroid metabolism; cholesterol metabolism.
CC       {ECO:0000250|UniProtKB:P49675}.
CC   -!- SUBUNIT: May interact with TSPO. {ECO:0000250|UniProtKB:P79245}.
CC   -!- SUBCELLULAR LOCATION: Mitochondrion {ECO:0000250|UniProtKB:P51557}.
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DR   EMBL; AF031697; AAC04704.1; -; mRNA.
DR   EMBL; AF031696; AAC04703.1; -; mRNA.
DR   RefSeq; NP_001075269.2; NM_001081800.2.
DR   AlphaFoldDB; O46689; -.
DR   SMR; O46689; -.
DR   STRING; 9796.ENSECAP00000023633; -.
DR   PaxDb; O46689; -.
DR   GeneID; 100009707; -.
DR   KEGG; ecb:100009707; -.
DR   CTD; 6770; -.
DR   InParanoid; O46689; -.
DR   UniPathway; UPA00296; -.
DR   Proteomes; UP000002281; Unplaced.
DR   GO; GO:0005758; C:mitochondrial intermembrane space; IBA:GO_Central.
DR   GO; GO:0015485; F:cholesterol binding; IBA:GO_Central.
DR   GO; GO:0120020; F:cholesterol transfer activity; IEA:InterPro.
DR   GO; GO:0008203; P:cholesterol metabolic process; IEA:UniProtKB-UniPathway.
DR   GO; GO:0032367; P:intracellular cholesterol transport; IBA:GO_Central.
DR   GO; GO:0050810; P:regulation of steroid biosynthetic process; IBA:GO_Central.
DR   GO; GO:0006694; P:steroid biosynthetic process; IBA:GO_Central.
DR   CDD; cd08905; START_STARD1-like; 1.
DR   Gene3D; 3.30.530.20; -; 1.
DR   InterPro; IPR029866; StAR.
DR   InterPro; IPR000799; StAR-like.
DR   InterPro; IPR023393; START-like_dom_sf.
DR   InterPro; IPR002913; START_lipid-bd_dom.
DR   PANTHER; PTHR46489; PTHR46489; 1.
DR   Pfam; PF01852; START; 1.
DR   PRINTS; PR00978; STARPROTEIN.
DR   SMART; SM00234; START; 1.
DR   PROSITE; PS50848; START; 1.
PE   2: Evidence at transcript level;
KW   Lipid transport; Lipid-binding; Mitochondrion; Phosphoprotein;
KW   Reference proteome; Steroidogenesis; Transit peptide; Transport.
FT   TRANSIT         1..63
FT                   /note="Mitochondrion"
FT                   /evidence="ECO:0000250"
FT   CHAIN           64..285
FT                   /note="Steroidogenic acute regulatory protein,
FT                   mitochondrial"
FT                   /id="PRO_0000033315"
FT   DOMAIN          67..280
FT                   /note="START"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00197"
FT   MOD_RES         57
FT                   /note="Phosphoserine; by PKA"
FT                   /evidence="ECO:0000250|UniProtKB:P49675"
FT   MOD_RES         195
FT                   /note="Phosphoserine; by PKA"
FT                   /evidence="ECO:0000250|UniProtKB:P49675"
SQ   SEQUENCE   285 AA;  31853 MW;  B0360EF93299727D CRC64;
     MLLATFKLCA GSSYRHVRNM KGLRHQAALA IGQELNWRAP GGPTQSGWIN QVRRQSSLLG
     SQLEDTLYSD QELAYIQQGE EAMQKALGIL RNQEGWKEEN QQANGDKVLS KVVPDVGKVF
     RLEVEVDQPM ERLYEELVER MEAMGEWNPN VKEIKVLQKI GKDTVITHEL AAESAGNLVG
     PRDFVSVRCA KRRGSTCVLA GMATQFEEMP EQKGVIRAEH GPTCMVLHPL AGSPSKTKLT
     WLLSIDLKGW LPKTIINQVL SQTQVDFANH LRKRLESSPA PEARC