Regulation of the Na(+)-coupled glutamate transporter EAAT3 by PIKfyve

Klaus, Fabian and Gehring, Eva-Maria and Zürn, Agathe and Laufer, Joerg and Lindner, Ricco and Strutz-Seebohm, Nathalie and Tavaré, Jeremy M. and Rothstein, Jeffrey D. and Boehmer, Christoph and Palmada, Monica and Gruner, Ivonne and Lang, Undine E. and Seebohm, Guiscard and Lang, Florian. (2009) Regulation of the Na(+)-coupled glutamate transporter EAAT3 by PIKfyve. Neurochemistry International, 54 (5-6). pp. 372-377.

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The Na(+), glutamate cotransporter EAAT3 is expressed in a wide variety of tissues. It accomplishes transepithelial transport and the cellular uptake of acidic amino acids. Regulation of EAAT3 activity involves a signaling cascade including the phosphatidylinositol-3 (PI3)-kinase, the phosphoinositide dependent kinase PDK1, and the serum and glucocorticoid inducible kinase SGK1. Targets of SGK1include the mammalian phosphatidylinositol-3-phosphate-5-kinase PIKfyve (PIP5K3). The present experiments explored whether PIKfyve participates in the regulation of EAAT3 activity. To this end,EAAT3 was expressed in Xenopus oocytes with or without SGK1 and/or PIKfyve and glutamate-induced current (I(glu)) determined by dual electrode voltage clamp. In Xenopus oocytes expressing EAAT3 but not in water injected oocytes glutamate induced an inwardly directed I(glu). Coexpression of either, SGK1 orPIKfyve, significantly enhanced I(glu) in EAAT3 expressing oocytes. The increased I(glu) was paralleled by increased EAAT3 protein abundance in the oocyte cell membrane. I(glu) and EAAT3 protein abundance were significantly larger in oocytes coexpressing EAAT3, SGK1 and PIKfyve than in oocytes expressingEAAT3 and either, SGK1 or PIKfyve, alone. Coexpression of the inactive SGK1 mutant (K127N)SGK1 did not significantly alter I(glu) in EAAT3 expressing oocytes and completely reversed the stimulating effect ofPIKfyve coexpression on I(glu). The stimulating effect of PIKfyve on I(glu) was abolished by replacement of the serine by alanine in the SGK consensus sequence ((S318A)PIKfyve). Moreover, additional coexpression of(S318A)PIKfyve significantly blunted I(glu) in Xenopus oocytes coexpressing SGK1 and EAAT3. The observations demonstrate that PIKfyve participates in EAAT3 regulation likely downstream of SGK1.
Faculties and Departments:03 Faculty of Medicine > Bereich Psychiatrie (Klinik) > Erwachsenenpsychiatrie UPK > Erwachsenenpsychiatrie (Lang)
03 Faculty of Medicine > Departement Klinische Forschung > Bereich Psychiatrie (Klinik) > Erwachsenenpsychiatrie UPK > Erwachsenenpsychiatrie (Lang)
UniBasel Contributors:Lang, Undine
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:30 Nov 2020 16:07
Deposited On:30 Nov 2020 16:07

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