title: Stimulation of the creatine transporter SLC6A8 by the protein kinase mTOR.
abstract: Cellular accumulation of creatine is accomplished by the Na(+), Cl(-), and creatine transporter CreaT (SLC6A8). The mammalian target of rapamycin (mTOR) is a kinase stimulating cellular nutrient uptake. The present experiments explored whether SLC6A8 is regulated by mTOR. In Xenopus oocytes expressing SLC6A8 but not in water injected oocytes, creatine-induced a current which was significantly enhanced by coexpression of mTOR. Kinetic analysis revealed that mTOR enhanced maximal current without significantly altering affinity. Preincubation of the oocytes for 32 h with rapamycin (50 nM) decreased the creatine-induced current and abrogated its stimulation by mTOR. The effect of mTOR on CreaT was blunted by additional coexpression of the inactive mutant of the serum and glucocorticoid-inducible kinase (K119N)SGK1 and mimicked by coexpression of wild type SGK1. In conclusion, mTOR stimulates the creatine transporter SLC6A8 through mechanisms at least partially shared by the serum and glucocorticoid-inducible kinase SGK1.
authors.affiliation: Department of Physiology I, University of Tübingen, Germany.
authors.forename: Manzar
authors.initials: M
authors.lastname: Shojaiefard
authors.forename: David L
authors.initials: DL
authors.lastname: Christie
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000818:Animals; D002417:Cattle; D003401:Creatine / Q000378:metabolism; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases; D014981:Xenopus; D000099184:Serum-Glucocorticoid Regulated Kinases
chemical_list: D003401:Creatine; D017874:Immediate-Early Proteins; D026901:Membrane Transport Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; D000099184:Serum-Glucocorticoid Regulated Kinases; C080679:creatine transporter