PKC phosphorylation regulates mGluR5 trafficking by enhancing binding of Siah-1A.
PKC phosphorylation regulates mGluR5 trafficking by enhancing binding of Siah-1A.
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DOI：
10.1523/jneurosci.1964-12.2012
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发表时间：
2012-11-14
期刊：
影响因子：
--
通讯作者：
Roche KW
中科院分区：
文献类型：
--
作者：
Ko SJ;Isozaki K;Kim I;Lee JH;Cho HJ;Sohn SY;Oh SR;Park S;Kim DG;Kim CH;Roche KW
Glutamate is the major excitatory neurotransmitter in the mammalian CNS and acts on both ionotropic and metabotropic glutamate receptors (mGluRs). The mGluRs are widely distributed in the CNS and modulate a variety of neuronal processes including neurotransmitter release and ion channel function. In hippocampus and cortex, mGluR5 is highly expressed and plays an important role in the regulation of synaptic plasticity. CaM binding dynamically regulates mGluR5 surface expression; however, the mechanisms linking CaM to mGluR5 trafficking are not clear. Recent studies showed that CaM binding to mGluR7 regulates its trafficking in a phosphorylation-dependent manner by disrupting the binding of PICK1. The E3 ligase seven in absentia homolog (Siah)-1A binds to mGluR5 and competes with CaM binding making it an intriguing molecule to regulate phosphorylation-dependent trafficking of mGluR5. In the present study, we find that CaM competes with Siah-1A for mGluR5 binding in a phosphorylation-dependent manner in rat hippocampal neurons. Specifically, phosphorylation of mGluR5 S901 favors Siah-1A binding by displacing CaM. We identified critical residues regulating Siah-1A binding to mGluR5 and showed that binding is essential for the Siah-1A effects on mGluR5 trafficking. Siah-1A binding decreases mGluR5 surface expression and increases endosomal trafficking and lysosomal degradation of mGluR5. Thus CaM-regulated Siah-1A binding to mGluR5 dynamically regulates mGluR5 trafficking. These findings support a conserved role for CaM in regulating mGluR trafficking by PKC-dependent regulation of receptor binding proteins.
