Hyperphosphorylation of CREB in human dopaminergic neurons: a kinetic study of cellular distribution of total CREB and phospho-CREB following oxidative stress.
The neurotoxin, 6-hydroxy dopamine (6-OHDA)-induced oxidative stress causes alterations in intracellular signalling events and activates cellular and molecular mechanisms leading to the degeneration of the dopamine-containing neurons (DCNs). The cyclic-AMP response element-binding protein (CREB) modulates the transcription of mitochondrial and nuclear genes upon phosphorylation. However, oxidative stress disrupts CREB functions and inhibits CREB signalling pathways. We have measured the activities and levels of both total CREB and its phosphorylated form (phospho-CREB) in cytosolic, mitochondrial and nuclear compartments in control (untreated) and stressed (6-OHDA-treated) DCN, differentiated from the ReNVM cell line (dDCN) at 0, 24 and 72 h time points following oxidative stress. Our results indicate that CREB phosphorylation occurs in all three subcellular locations. It further shows significant disruption of the phosphorylation process by 6-OHDA treatment and shows tridirectional trafficking of total CREB and phospho-CREB between cytosol, mitochondria and nucleus following oxidative stress induced by 6-OHDA treatment. In conclusion, our results indicate the presence of specific signalling molecules in all the compartments studied and their involvement in the signal transduction processes, where total CREB and phospho-CREB levels and activities are either upregulated or downregulated to balance each other for their roles.
Department of Life Sciences, Institute of Biomedical & Environmental Science and Technology, Faculty of Creative Arts, Technologies & Science, University of Bedfordshire, Bedfordshire, UK. bushra.ahmed@beds.ac.uk
Bushra Y
BY
Ahmed
Omair
O
Husnain
Richard
R
Stafford
Martyn
M
Howard
Abhay S
AS
Gujar
Vimal
V
Moradiya
Kunjan K
KK
Patel
Sikander
S
Sihotra
D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D003627:Data Interpretation, Statistical; D059290:Dopaminergic Neurons / Q000378:metabolism*; D006801:Humans; D006892:Hydroxydopamines; D007700:Kinetics; D024101:Mitochondrial Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D058953:Neural Stem Cells / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010300:Parkinson Disease / Q000378:metabolism; D010766:Phosphorylation
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D006892:Hydroxydopamines; D024101:Mitochondrial Proteins; D009419:Nerve Tissue Proteins