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The secretogranin II gene is a signal integrator of glutamate and dopamine inputs
Author(s) -
Iwase Katsuro,
Ishihara Akinori,
Yoshimura Shuntaro,
Andoh Yoshio,
Kato Masaki,
Seki Naohiko,
Matsumoto Eriko,
Hiwasa Takaki,
Muller Dominique,
Fukunaga Kohji,
Takiguchi Masaki
Publication year - 2014
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.12467
Subject(s) - protein kinase a , dopaminergic , glutamate receptor , dopamine , microbiology and biotechnology , biology , chemistry , phosphorylation , biochemistry , neuroscience , receptor
Cooperative gene regulation by different neurotransmitters likely underlies the long‐term forms of associative learning and memory, but this mechanism largely remains to be elucidated. Following cDNA microarray analysis for genes regulated by Ca 2+ or cAMP , we found that the secretogranin II gene ( Scg2 ) was cooperatively activated by glutamate and dopamine in primary cultured mouse hippocampal neurons. The Ca 2+ chelator 1,2‐bis(2‐aminophenoxy)ethane‐ N , N , N ’, N ’‐tetraacetic acid acetoxymethyl ester (BAPTA‐AM) and the mitogen‐activated protein kinase (MAPK) kinase (MEK) inhibitor PD98059 prevented Scg2 activation by glutamate or dopamine; thus, the Ca 2+ /MEK pathway is predicted to include a convergence point(s) of glutamatergic and dopaminergic signaling. Unexpectedly, the protein kinase A inhibitor KT5720 enhanced Scg2 activation by dopamine. The protein‐synthesis inhibitor cycloheximide also enhanced Scg2 activation, and the proteasome inhibitor ZLLLH diminished the KT5720‐mediated augmentation of Scg2 activation. These results are concordant with the notion that dopaminergic input leads to accumulation of a KT5720‐sensitive transcriptional repressor, which is short‐lived because of rapid degradation by proteasomes. This repression pathway may effectively limit the time window permissive to Scg2 activation by in‐phase glutamate and dopamine inputs via the Ca 2+ /MEK pathway. We propose that the regulatory system of Scg2 expression is equipped with machinery that is refined for the signal integration of in‐phase synaptic inputs.We proposed hypothetical mechanism for the regulation of the secretogranin II gene as a signal integrator of glutamate and dopamine inputs. Glutamate or dopamine activates the Ca 2+ /MEK/ERK pathway, which thus contributes to the signal integration. Concurrently, activation of the PKA inhibitor KT5720‐sensitive pathway by dopamine leads to accumulation of the repressor protein X that is otherwise susceptible to proteasome degradation. This repression system may determine the time window permissive to the cooperative activation by in‐phase glutamate and dopamine inputs.