title: Carnitine precursor γ-butyrobetaine is a novel substrate of the Na(+)- and Cl(-)-dependent GABA transporter Gat2.
abstract: To study transport of the carnitine precursor gamma-butyrobetaine (GBB) by rat liver-specific GABA transporter 2 (rGat2), we measured the uptake of deuterated GBB (d(3)-GBB) by Xenopus oocytes expressing rGat2. rGat2-mediated d(3)-GBB uptake was Na(+) and Cl(-) dependent, and was saturable with a K(m) value of 70.6 ± 34.8 µM. In carnitine transporter Octn2-deficient Jvs mice, mRNA expression of mGat3, the mouse ortholog of GAT2, decreased in liver, but increased in brain, while mRNA expression of mBbox1, which hydroxylates GBB to carnitine, increased in kidney and brain. These results indicate that GAT2 plays a role in transmembrane transport of GBB.
authors: Department of Membrane Transport and Biopharmaceutics, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Japan.
authors: Takeo
authors: T
authors: Nakanishi
authors: Yoko
authors: Y
authors: Fukuyama
authors: Masaharu
authors: M
authors: Fujita
authors: Yoshiyuki
authors: Y
authors: Shirasaka
authors: Ikumi
authors: I
authors: Tamai
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001622:Betaine / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002331:Carnitine / Q000378:metabolism*; D050485:GABA Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009865:Oocytes / Q000378:metabolism; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D014982:Xenopus laevis
chemical_list: D050485:GABA Plasma Membrane Transport Proteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D001622:Betaine; C002889:gamma-butyrobetaine; D000217:Acyltransferases; C021802:2-acylglycerol O-acyltransferase; D002331:Carnitine