Rottlerin inhibits (Na+, K+)-ATPase activity in brain tissue and alters D-aspartate dependent redistribution of glutamate transporter GLAST in cultured astrocytes.
The naturally occurring toxin rottlerin has been used by other laboratories as a specific inhibitor of protein kinase C-delta (PKC-delta) to obtain evidence that the activity-dependent distribution of glutamate transporter GLAST is regulated by PKC-delta mediated phosphorylation. Using immunofluorescence labelling for GLAST and deconvolution microscopy we have observed that D-aspartate-induced redistribution of GLAST towards the plasma membranes of cultured astrocytes was abolished by rottlerin. In brain tissue in vitro, rottlerin reduced apparent activity of (Na+, K+)-dependent ATPase (Na+, K+-ATPase) and increased oxygen consumption in accordance with its known activity as an uncoupler of oxidative phosphorylation ("metabolic poison"). Rottlerin also inhibited Na+, K+-ATPase in cultured astrocytes. As the glutamate transport critically depends on energy metabolism and on the activity of Na+, K+-ATPase in particular, we suggest that the metabolic toxicity of rottlerin and/or the decreased activity of the Na+, K+-ATPase could explain both the glutamate transport inhibition and altered GLAST distribution caused by rottlerin even without any involvement of PKC-delta-catalysed phosphorylation in the process.
Nguyen
Khoa T D
KT
School of Medical Sciences and Bosch Institute for Biomedical Research, The University of Sydney, Sydney, NSW 2006, Australia.
Shin
Jae-Won
JW
Rae
Caroline
C
Nanitsos
Ellas K
EK
Acosta
Gabriela B
GB
Pow
David V
DV
Buljan
Vlado
V
Bennett
Maxwell R
MR
Else
Paul L
PL
Balcar
Vladimir J
VJ
D000098:Acetophenones / Q000494:pharmacology*; D027322:Amino Acid Transport System X-AG / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D001578:Benzopyrans / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D026603:D-Aspartic Acid / Q000032:analysis / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D027341:Excitatory Amino Acid Transporter 1 / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D000098:Acetophenones; D027322:Amino Acid Transport System X-AG; D001578:Benzopyrans; D027341:Excitatory Amino Acid Transporter 1; C493392:Slc1a3 protein, rat; D026603:D-Aspartic Acid; C085746:rottlerin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase