SLCO4A1
Developmental stage
Expressed in fetal brain, heart, kidney, liver, lung, skeletal muscle, spleen and pancreas (PubMed:10873595).
Domain
A conserved histidine residue in the third TMD (His-191) may play an essential role in the pH sensitivity of SLCO4A1/OATP4A1-mediated substrate transport.
Function
Organic anion antiporter with apparent broad substrate specificity. Recognizes various substrates including thyroid hormones 3,3',5-triiodo-L-thyronine (T3), L-thyroxine (T4) and 3,3',5'-triiodo-L-thyronine (rT3), conjugated steroids such as estrone 3-sulfate and estradiol 17-beta glucuronide, bile acids such as taurocholate and prostanoids such as prostaglandin E2, likely operating in a tissue-specific manner (PubMed:10873595, PubMed:19129463, PubMed:30343886). May be involved in uptake of metabolites from the circulation into organs such as kidney, liver or placenta. Possibly drives the selective transport of thyroid hormones and estrogens coupled to an outward glutamate gradient across the microvillous membrane of the placenta (PubMed:30343886). The transport mechanism, its electrogenicity and potential tissue-specific counterions remain to be elucidated (Probable).
Sequence Similarities
Belongs to the organo anion transporter (TC 2.A.60) family.
Tissue Specificity
Widely expressed (PubMed:10873595, PubMed:11316767). Expressed in placental trophoblasts (PubMed:10873595, PubMed:12409283). Expressed in pancreas, kidney, skeletal muscle, liver, lung, brain, heart, colon, small intestine, ovary, testis, prostate, thymus and spleen. In testis, primarily localized to Leydig cells (PubMed:35307651).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
Alternative names
OATP1, OATP4A1, OATPE, SLC21A12, SLCO4A1, Solute carrier organic anion transporter family member 4A1, Colon organic anion transporter, Organic anion transporter polypeptide-related protein 1, Organic anion-transporting polypeptide E, Sodium-independent organic anion transporter E, Solute carrier family 21 member 12, OATP-RP1, OATPRP1, POAT, OATP-E