Downregulation of the cAMP/PKA pathway in PC12 cells overexpressing NCS-1.
It is well known that dopamine imbalances are associated with many psychiatric disorders and that the dopaminergic receptor D₂ is the main target of antipsychotics. Recently it was shown that levels of two proteins implicated in dopaminergic signaling, Neuronal calcium sensor-1 (NCS-1) and DARPP-32, are altered in the prefrontal cortex (PFC) of both schizophrenic and bipolar disorder patients. NCS-1, which inhibits D₂ internalization, is upregulated in the PFC of both patients. DARPP-32, which is a downstream effector of dopamine signaling, integrates the pathways of several neurotransmitters and is downregulated in the PFC of both patients. Here, we used PC12 cells stably overexpressing NCS-1 (PC12-NCS-1 cells) to address the function of this protein in DARPP-32 signaling pathway in vitro. PC12-NCS-1 cells displayed downregulation of the cAMP/PKA pathway, with decreased levels of cAMP and phosphorylation of CREB at Ser133. We also observed decreased levels of total and phosphorylated DARPP-32 at Thr34. However, these cells did not show alterations in the levels of D₂ and phosphorylation of DARPP-32 at Thr75. These results indicate that NCS-1 modulates PKA/cAMP signaling pathway. Identification of the cellular mechanisms linking NCS-1 and DARPP-32 may help in the understanding the signaling machinery with potential to be turned into targets for the treatment of schizophrenia and other debilitating psychiatric disorders.
Souza
Bruno R
BR
Departamento de Saúde Mental, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. brunorezendesouza@gmail.com
Torres
Karen C L
KC
Miranda
Débora M
DM
Motta
Bernardo S
BS
Caetano
Fernando S
FS
Rosa
Daniela V F
DV
Souza
Renan P
RP
Giovani
Antônio
A
Carneiro
Daniel S
DS
Guimarães
Melissa M
MM
Martins-Silva
Cristina
C
Reis
Helton J
HJ
Gomez
Marcus V
MV
Jeromin
Andreas
A
Romano-Silva
Marco A
MA
D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics / Q000502:physiology; D051580:Neuronal Calcium-Sensor Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats; D017448:Receptors, Dopamine D2 / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014162:Transfection; D015854:Up-Regulation / Q000235:genetics
D017362:Cyclic AMP Response Element-Binding Protein; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides; C497930:Ppp1r1b protein, rat; D017448:Receptors, Dopamine D2; C101464:frequenin calcium sensor proteins; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases