Airas J M, Betz H, El Far O
Department of Neurochemistry, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, 60528, Frankfurt, Germany.
FEBS Lett. 2001 Apr 6;494(1-2):60-3. doi: 10.1016/s0014-5793(01)02311-0.
Group III metabotropic glutamate receptors (mGluRs) serve as presynaptic receptors that mediate feedback inhibition of glutamate release via a Ca(2+)/calmodulin (CaM)-dependent mechanism. In vitro phosphorylation of mGluR7A by protein kinase C (PKC) prevents its interaction with Ca(2+)/CaM. In addition, activation of PKC leads to an inhibition of mGluR signaling. Here, we demonstrate that disrupting CaM binding to mGluR7A by PKC in vitro is due to phosphorylation of a highly conserved serine residue, S862. We propose charge neutralization of the CaM binding consensus sequence resulting from phosphorylation to constitute a general mechanism for the regulation of presynaptic mGluR signaling.
Ⅲ型代谢型谷氨酸受体（mGluRs）作为突触前受体，通过Ca(2+)/钙调蛋白（CaM）依赖性机制介导谷氨酸释放的反馈抑制。蛋白激酶C（PKC）对mGluR7A的体外磷酸化可阻止其与Ca(2+)/CaM相互作用。此外，PKC的激活会导致mGluR信号传导受到抑制。在此，我们证明PKC在体外破坏CaM与mGluR7A的结合是由于一个高度保守的丝氨酸残基S862的磷酸化所致。我们提出，磷酸化导致的CaM结合共有序列的电荷中和构成了调节突触前mGluR信号传导的一般机制。
