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Regulation of the mouse retinal taurine transporter (TAUT) by protein kinases in Xenopus oocytes
Author(s) -
Loo Donald D.F.,
Hirsch Jochen R.,
Sarkar Hemanta K.,
Wright Ernest M.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00823-x
Subject(s) - protein kinase c , xenopus , activator (genetics) , voltage clamp , transporter , protein kinase a , chemistry , taurine , biology , kinase , microbiology and biotechnology , biochemistry , membrane potential , receptor , amino acid , gene
The goal was to investigate the role of protein kinases in modulating taurine transporter activity in Xenopus laevis oocytes expressing the mouse retinal Na + /C − /taurine transporter. The currents generated by the taurine transporter were studied with a two‐electrode voltage clamp and we recorded the maximal current ( I max ), presteady‐state charge transfer Q , and membrane capacitance C m . 8‐BR‐cAMP, a membrane‐permeable activator of the cAMP‐dependent protein kinase (PKA), decreased I max (41%), Q (41%) and C m (10%). Similarly, 1 μM sn ‐1,2‐dioctanoylglycerol (DOG), an activator of the Ca 2+ I diacylglycerol‐dependent protein kinase (PKC), decreased I max (56%), Q (37%), and C m (9%). Calyculin A, a specific inhibitor of protein phosphatases 1 and 2A, also produced effects similar to those of 8‐Br‐cAMP and DOG, and decreased I max (64%), Q (38%), and C m (10%). We conclude that the taurine transporter is regulated by activators of PKA and PKC, and regulation occurs largely by changes in the number of transporters in the plasma membrane.