BACKGROUND/AIMS: Transport regulation involves several kinases including SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1), which are under control of WNK (with-no-K[Lys]) kinases. The present study explored whether SPAK and/or OSR1 participate in the regulation of the creatine transporter CreaT (SLC6A8), which accomplishes Na+ coupled cellular uptake of creatine in several tissues including kidney, intestine, heart, skeletal muscle and brain. METHODS: cRNA encoding SLC6A8 was injected into Xenopus laevis oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 and catalytically inactive (D164A)OSR1. Transporter activity was determined from creatine (1 mM) induced current utilizing dual electrode voltage clamp. RESULTS: Coexpression of wild-type SPAK and of (T233E)SPAK, but not of (T233A)SPAK or of (D212A)SPAK was followed by a significant decrease of creatine induced current in SLC6A8 expressing oocytes. Coexpression of SPAK significantly decreased maximal transport rate. Coexpression of wild-type OSR1, (T185E)OSR1 and (T185A)OSR1 but not of (D164A)OSR1 significantly negatively regulated SLC6A8 activity. OSR1 again decreased significantly maximal transport rate. CONCLUSIONS: Both, SPAK and OSR1, are negative regulators of the creatine transporter SLC6A8.
BACKGROUND/AIMS: Transport regulation involves several kinases including SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1), which are under control of WNK (with-no-K[Lys]) kinases. The present study explored whether SPAK and/or OSR1 participate in the regulation of the creatine transporter CreaT (SLC6A8), which accomplishes Na+ coupled cellular uptake of creatine in several tissues including kidney, intestine, heart, skeletal muscle and brain. METHODS: cRNA encoding SLC6A8 was injected into Xenopus laevis oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active (T233E)SPAK, WNK insensitive (T233A)SPAK, catalytically inactive (D212A)SPAK, wild-type OSR1, constitutively active (T185E)OSR1, WNK insensitive (T185A)OSR1 and catalytically inactive (D164A)OSR1. Transporter activity was determined from creatine (1 mM) induced current utilizing dual electrode voltage clamp. RESULTS: Coexpression of wild-type SPAK and of (T233E)SPAK, but not of (T233A)SPAK or of (D212A)SPAK was followed by a significant decrease of creatine induced current in SLC6A8 expressing oocytes. Coexpression of SPAK significantly decreased maximal transport rate. Coexpression of wild-type OSR1, (T185E)OSR1 and (T185A)OSR1 but not of (D164A)OSR1 significantly negatively regulated SLC6A8 activity. OSR1 again decreased significantly maximal transport rate. CONCLUSIONS: Both, SPAK and OSR1, are negative regulators of the creatine transporter SLC6A8.
Authors: Caroline H T Hall; J Scott Lee; Emily M Murphy; Mark E Gerich; Rachael Dran; Louis E Glover; Zuhair I Abdulla; Matthew R Skelton; Sean P Colgan Journal: Gastroenterology Date: 2020-05-17 Impact factor: 22.682
Authors: Kayla Raider; Delin Ma; Janna L Harris; Isabella Fuentes; Robert S Rogers; Joshua L Wheatley; Paige C Geiger; Hung-Wen Yeh; In-Young Choi; William M Brooks; John A Stanford Journal: Neurochem Int Date: 2016-04-26 Impact factor: 3.921
Authors: Jamshed Warsi; Zohreh Hosseinzadeh; Bernat Elvira; Lisann Pelzl; Ekaterina Shumilina; Dong-Er Zhang; Karl S Lang; Philipp A Lang; Florian Lang Journal: PLoS One Date: 2015-06-05 Impact factor: 3.240
Authors: Ye Bi; Chunmei Li; Yiqian Zhang; Yunman Wang; Shan Chen; Qiang Yue; Robert S Hoover; Xiaonan H Wang; Eric Delpire; Douglas C Eaton; Jieqiu Zhuang; Hui Cai Journal: Front Physiol Date: 2020-07-02 Impact factor: 4.755
Authors: Cíntia B Santos-Rebouças; Raquel Boy; Evelyn Q Vianna; Andressa P Gonçalves; Rafael M Piergiorge; Bianca B Abdala; Jussara M Dos Santos; Veluma Calassara; Filipe B Machado; Enrique Medina-Acosta; Márcia M G Pimentel Journal: Front Genet Date: 2020-03-04 Impact factor: 4.599