J Biol Chem 1999,
PMID: 10187789
Matsushita, M; Nairn, A C
Several recent studies have shown that Ca2+/calmodulin-dependent protein kinase I (CaMKI) is phosphorylated and activated by a protein kinase (CaMKK) that is itself subject to regulation by Ca2+/calmodulin. In the present study, we demonstrate that this enzyme cascade is regulated by cAMP-mediated activation of cAMP-dependent protein kinase (PKA). In vitro, CaMKK is phosphorylated by PKA and this is associated with inhibition of enzyme activity. The major site of phosphorylation is threonine 108, although additional sites are phosphorylated with lower efficiency. In vitro, CaMKK is also phosphorylated by CaMKI at the same sites as PKA, suggesting that this regulatory phosphorylation might play a role as a negative-feedback mechanism. In intact PC12 cells, activation of PKA with forskolin resulted in a rapid inhibition of both CaMKK and CaMKI activity. In hippocampal slices CaMKK was phosphorylated under basal conditions, and activation of PKA led to an increase in phosphorylation. Two-dimensional phosphopeptide mapping indicated that activation of PKA led to increased phosphorylation of multiple sites including threonine 108. These results indicate that in vitro and in intact cells the CaMKK/CaMKI cascade is subject to inhibition by PKA-mediated phosphorylation of CaMKK. The phosphorylation and inhibition of CaMKK by PKA is likely to be involved in modulating the balance between cAMP- and Ca2+-dependent signal transduction pathways.
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Text Mining Data
CaMKI ⊣ PKA: "
In intact PC12 cells, activation of
PKA with forskolin resulted in a rapid
inhibition of both CaMKK and
CaMKI activity
"
CaMKK ⊣ PKA: "
In intact PC12 cells, activation of PKA with forskolin resulted in a rapid inhibition of both CaMKK and CaMKI activity
"
CaMKK → PKA: "
These results indicate that in vitro and in intact cells the CaMKK/CaMKI cascade is subject to inhibition by PKA mediated phosphorylation of CaMKK
"
Manually curated Databases
-
IRef Biogrid Interaction:
PRKACA
—
CAMKK2
(direct interaction, enzymatic study)
-
IRef Biogrid Interaction:
CAMK1
—
CAMKK2
(direct interaction, enzymatic study)
-
IRef Hprd Interaction:
CAMKK1
—
CAMK1
(in vivo)
In total, 3 gene pairs are associated to this article in curated databases