title: Downregulation of Glutamate Transporter EAAT4 by Conditional Knockout of Rheb1 in Cerebellar Purkinje Cells.
abstract: Excitatory amino acid transporter 4 (EAAT4) is believed to be critical to the synaptic activity of cerebellar Purkinje cells by limiting extracellular glutamate concentrations and facilitating the induction of long-term depression. However, the modulation of EAAT4 expression has not been elucidated. It has been shown that Ras homolog enriched in brain (Rheb)/mammalian target of rapamycin (mTOR) signaling plays essential roles in the regulation of protein translation, cell size, and cell growth. In addition, we previously found that a cascade including mTOR suppression and Akt activation induces increased expression of EAAT2 in astrocytes. In the present work, we explored whether Rheb/mTOR signaling is involved in the regulation of EAAT4 expression using conditional Rheb1 knockout mice. Our results demonstrated that Rheb1 deficiency resulted in the downregulation of EAAT4 expression, as well as decreased activity of mTOR and increased activity of Akt. The downregulation of EAAT4 was also confirmed by reduced EAAT4 currents and slowed kinetics of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor-mediated currents. On the other hand, conditional knockout of Rheb1 did not alter the morphology of Purkinje cell layer and the number of Purkinje cells. Overall, our findings suggest that small GTPase Rheb1 is a modulator in the expression of EAAT4 in Purkinje cells.
authors.affiliation: Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, Department of Physiology and Pharmacology, Ningbo University School of Medicine, Ningbo, 315211, China.
authors.forename: Nan-Wei
authors.initials: NW
authors.lastname: Jiang
authors.affiliation: Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China.
authors.forename: De-Juan
authors.initials: DJ
authors.lastname: Wang
authors.affiliation: Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China.
authors.forename: Ya-Jun
authors.initials: YJ
authors.lastname: Xie
authors.affiliation: Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China.|Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Li-Da
authors.initials: LD
authors.lastname: Su
authors.affiliation: Shenzhen Key laboratory for Molecular Biology of Neural Development, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
authors.forename: Huashun
authors.initials: H
authors.lastname: Li
authors.affiliation: Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, Department of Physiology and Pharmacology, Ningbo University School of Medicine, Ningbo, 315211, China. wangqinwen@nbu.edu.cn.
authors.forename: Qin-Wen
authors.initials: QW
authors.lastname: Wang
authors.affiliation: Department of Neurobiology, Zhejiang University School of Medicine, 866 Yu Hang Tang Road, Hangzhou, 310058, China. yshen@zju.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Shen
mesh_terms: D000818:Animals; D015153:Blotting, Western; D050581:Excitatory Amino Acid Transporter 4 / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D000076222:Mechanistic Target of Rapamycin Complex 1; D008564:Membrane Potentials / Q000502:physiology; D018345:Mice, Knockout; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011689:Purkinje Cells / Q000166:cytology / Q000378:metabolism*; D000076205:Ras Homolog Enriched in Brain Protein; D018091:Receptors, AMPA; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059010:Single-Cell Analysis; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D050581:Excitatory Amino Acid Transporter 4; D046912:Multiprotein Complexes; D009479:Neuropeptides; D000076205:Ras Homolog Enriched in Brain Protein; D018091:Receptors, AMPA; C490213:Rheb protein, mouse; C493390:Slc1a6 protein, mouse; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D020559:Monomeric GTP-Binding Proteins
keywords: Cerebellum; EAAT4; Glutamate transporter; Purkinje cell; Rheb1