Activated CaMKIIαBinds to the mGlu₅Metabotropic Glutamate Receptor and Modulates Calcium Mobilization

Abstract

Ca 21 /calmodulin-dependent protein kinase II (CaMKII) and metabotropic glutamate receptor 5 (mGlu 5 ) are critical signaling molecules in synaptic plasticity and learning/memory. Here, we demonstrate that mGlu 5 is present in CaMKIIa complexes isolated from mouse forebrain. Further in vitro characterization showed that the membrane-proximal region of the C-terminal domain (CTD) of mGlu 5a directly interacts with purified Thr286-autophosphorylated (activated) CaMKIIa. However, the binding of CaMKIIa to this CTD fragment is reduced by the addition of excess Ca 21 /calmodulin or by additional CaMKIIa autophosphorylation at non-Thr286 sites. Furthermore, in vitro binding of CaMKIIa is dependent on a tribasic residue motif Lys-Arg-Arg (KRR) at residues 866-868 of the mGlu 5a -CTD, and mutation of this motif decreases the coimmunoprecipitation of CaMKIIa with full-length mGlu 5a expressed in heterologous cells by about 50%. The KRR motif is required for two novel functional effects of coexpressing constitutively active CaMKIIa with mGlu 5a in heterologous cells. First, cell-surface biotinylation studies showed that CaMKIIa increases the surface expression of mGlu 5a . Second, using Ca 21 fluorimetry and single-cell Ca 21 imaging, we found that CaMKIIa reduces the initial peak of mGlu 5a -mediated Ca 21 mobilization by about 25% while doubling the relative duration of the Ca 21 signal. These findings provide new insights into the physical and functional coupling of these key regulators of postsynaptic signaling. [DK020593], and the Center for Stem Cell Biology. https://doi.org/10. 1124/mol.118.113142. s This article has supplemental material available at molpharm. aspetjournals.org.

Neuronal L-Type Calcium Channel Signaling to the Nucleus Requires a Novel CaMKIIα-Shank3 Interaction

“…3B). Examination of the amino acid sequence of Shank3 residues 931-1014 revealed a region sharing some similarity with recently characterized CaMKII binding domains in the N-terminal domain of the LTCC Ca V 1.3 ␣ subunit (Wang et al, 2017) and the C-terminal domain (CTD) of mGlu5 (Marks et al, 2018) (Fig. 3A).…”

“…All mice were housed on a 12 h light-dark cycle with food and water ad libitum. Camk2aϪ/Ϫ (referred to as CaMKII␣-KO) and Camk2a tm2Sva (RRID:MGI:3764491, referred to as CaMKII␣ T286A ) mice on a C57B/6J background were described previously (Giese et al, 1998;Marks et al, 2018). WT and homozygous littermates were generated using a HetxHet breeding strategy.…”

“…In addition, densin-180 can bind to both Ca V 1.3 LTCCs and CaMKII, thereby suppressing Ca 2ϩ -dependent inactivation of Ca V 1.3 and facilitating overall Ca 2ϩ entry via LTCCs (Jenkins et al, 2010;Jiao et al, 2011). A recent study also showed that CaMKII binding to mGlu5 metabotropic glutamate receptors modulates the mobilization of intracellular Ca 2ϩ stores (Marks et al, 2018). This emerging evidence supports the hypothesis that direct interactions of CaMKII with CaMKII-associated proteins (CaMKAPs) are important for synaptic signaling.…”

Acetylation of calmodulin regulates synaptic plasticity and fear learning

“…Regardless, our results indicate that CaM acetylation is important for the full activation of CaMKIIα and phosphorylation of GluR1 during LTP. In addition to the GluR1 subunit of AMPA receptor, CaMKIIα can interact with and phosphorylate a variety of synaptic proteins, which contribute to synaptic plasticity and learning ( 62 , 63 , 64 , 65 ). It will be interesting to study whether CaM acetylation regulates phosphorylation of other downstream target proteins of CaMKIIα.…”

International Union of Basic and Clinical Pharmacology. CXI. Pharmacology, Signaling, and Physiology of Metabotropic Glutamate Receptors

“…Eng et al, 2016;Gulia et al, 2017). Second messengeractivated kinases also provide negative feedback regulating cellular responses (iCa 2+ oscillations or receptor desensitization) through phosphorylation of intracellular loops and/or the C terminus (Kawabata et al, 1996;Gereau and Heinemann, 1998;Bhattacharya et al, 2004;Mundell et al, 2004;Kim et al, 2005;Ko et al, 2012;Jin et al, 2013aJin et al, ,b, 2018Raka et al, 2015;Uematsu et al, 2015;Vergouts et al, 2017;Yang et al, 2017;Marks et al, 2018). However, not all functional responses are equally influenced.…”