CREB activation induced by mitochondrial dysfunction is a new signaling pathway that impairs cell proliferation.
We characterized a new signaling pathway leading to the activation of cAMP-responsive element-binding protein (CREB) in several cell lines affected by mitochondrial dysfunction. In vitro kinase assays, inhibitors of several kinase pathways and overexpression of a dominant-negative mutant for calcium/calmodulin kinase IV (CaMKIV), which blocks the activation of CREB, showed that CaMKIV is activated by a mitochondrial activity impairment. A high calcium concentration leading to the disruption of the protein interaction with protein phosphatase 2A explains CaMKIV activation in these conditions. Transcrip tionally active phosphorylated CREB was also found in a rho0 143B human osteosarcoma cell line and in a MERRF cybrid cell line mutated for tRNA(Lys) (A8344G). We also showed that phosphorylated CREB is involved in the proliferation defect induced by a mitochondrial dysfunction. Indeed, cell proliferation inhibition can be prevented by CaMKIV inhibition and CREB dominant-negative mutants. Finally, our data suggest that phosphorylated CREB recruits p53 tumor suppressor protein, modifies its transcriptional activity and increases the expression of p21(Waf1/Cip1), a p53-regulated cyclin-dependent kinase inhibitor.
Arnould
T
T
Laboratoire de Biochimie et Biologie Cellulaire, University of Namur (FUNDP), 61 rue de Bruxelles, B-5000 Namur, Belgium. thierry.arnould@fundp.ac.be
Vankoningsloo
S
S
Renard
P
P
Houbion
A
A
Ninane
N
N
Demazy
C
C
Remacle
J
J
Raes
M
M
D000818:Animals; D001483:Base Sequence; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000502:physiology*; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D015398:Signal Transduction / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004272:DNA, Mitochondrial; D016159:Tumor Suppressor Protein p53; C517683:CAMK4 protein, human; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517685:Camk4 protein, mouse; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2