Negative Regulation of the Creatine Transporter SLC6A8 by SPAK and OSR1

• Main Authors: Myriam Fezai (Author), Bernat Elvira (Author), Jose Borras (Author), Mossadok Ben-Attia (Author), Zohreh Hoseinzadeh (Author), Florian Lang (Author)
• Format: Book
• Published: Karger Publishers, 2014-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

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 T233ESPAK, WNK insensitive T233ASPAK, catalytically inactive D212ASPAK, wild-type OSR1, constitutively active T185EOSR1, WNK insensitive T185AOSR1 and catalytically inactive D164AOSR1. Transporter activity was determined from creatine (1 mM) induced current utilizing dual electrode voltage clamp. Results: Coexpression of wild-type SPAK and of T233ESPAK, but not of T233ASPAK or of D212ASPAK 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, T185EOSR1 and T185AOSR1 but not of D164AOSR1 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.

Item Description

1420-4096
1423-0143
10.1159/000368465