N-cadherin modulates voltage activated calcium influx via RhoA, p120-catenin, and myosin-actin interaction

Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, 66160, USA.
Molecular and Cellular Neuroscience (Impact Factor: 3.84). 03/2009; 40(3):390-400. DOI: 10.1016/j.mcn.2008.12.007
Source: PubMed

ABSTRACT N-cadherin is a transmembrane adhesion receptor that contributes to neuronal development and synapse formation through homophilic interactions that provide structural-adhesive support to contacts between cell membranes. In addition, N-cadherin homotypic binding may initiate cell signaling that regulates neuronal physiology. In this study, we investigated signaling capabilities of N-cadherin that control voltage activated calcium influx. Using whole-cell voltage clamp recording of isolated inward calcium currents in freshly isolated chick ciliary ganglion neurons we show that the juxtamembrane region of N-cadherin cytoplasmic domain regulates high-threshold voltage activated calcium currents by interacting with p120-catenin and activating RhoA. This regulatory mechanism requires myosin interaction with actin. Furthermore, N-cadherin homophilic binding enhanced voltage activated calcium current amplitude in dissociated neurons that have already developed mature synaptic contacts in vivo. The increase in calcium current amplitude was not affected by brefeldin A suggesting that the effect is caused via direct channel modulation and not by increasing channel expression. In contrast, homotypic N-cadherin interaction failed to regulate calcium influx in freshly isolated immature neurons. However, RhoA inhibitors enhanced calcium current amplitude in these immature neurons, suggesting that the inhibitory effect of RhoA on calcium entry is regulated during neuronal development and synapse maturation. These results indicate that N-cadherin modulates voltage activated calcium entry by a mechanism that involves RhoA activity and its downstream effects on the cytoskeleton, and suggest that N-cadherin provides support for synaptic maturation and sustained synaptic activity by facilitating voltage activated calcium influx.

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Available from: Christopher S Theisen, Dec 22, 2014
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    • "Interestingly, when the Fura-2AM reporter was used, steady state levels of intracellular Ca2+ were found to be not affected by substrate coated recombinant N-cadherin suggesting that N-cadherin influences predominantly submembrane Ca2+ levels [40]. Whole cell voltage clamp recordings also showed that homophilic binding of N-cadherin on neuronal membranes to soluble N-cadherin or N-cadherin overexpressed in Chinese hamster ovary (CHO) cells increases amplitudes of Ca2+ currents in ciliary ganglion neurons indicating that homophilic interactions of N-cadherin are sufficient to activate a cellular mechanism that regulates Ca2+ influx [41]. "
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    ABSTRACT: Cell adhesion molecules (CAMs) play indispensable roles in the developing and mature brain by regulating neuronal migration and differentiation, neurite outgrowth, axonal fasciculation, synapse formation and synaptic plasticity. CAM-mediated changes in neuronal behavior depend on a number of intracellular signaling cascades including changes in various second messengers, among which CAM-dependent changes in intracellular Ca2+ levels play a prominent role. Ca2+ is an essential secondary intracellular signaling molecule that regulates fundamental cellular functions in various cell types, including neurons. We present a systematic review of the studies reporting changes in intracellular Ca2+ levels in response to activation of the immunoglobulin superfamily CAMs, cadherins and integrins in neurons. We also analyze current experimental evidence on the Ca2+ sources and channels involved in intracellular Ca2+ increases mediated by CAMs of these families, and systematically review the role of the voltage-dependent Ca2+ channels (VDCCs) in neurite outgrowth induced by activation of these CAMs. Molecular mechanisms linking CAMs to VDCCs and intracellular Ca2+ stores in neurons are discussed.
    Cell Communication and Signaling 12/2013; 11(1):94. DOI:10.1186/1478-811X-11-94 · 3.38 Impact Factor
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    • "Binding of p120-catenin to cadherins in glutamatergic presynaptic terminals contribute to presynaptic differentiation and clustering of synaptic vesicles (Lee et al., 2008), suggesting that coupling of p120-catenin to N-cadherin in postsynaptic cells may increase the activity of N-cadherin in presynaptic differentiation. As p120-catenin regulates RhoA and voltage-activated calcium influx in cholinergic neurons (Anastasiadis et al., 2000; Piccoli et al., 2004; Marrs et al., 2009), this results suggests that coupling and uncoupling of p120-catenin from N-cadherin may serve as a switch that regulates the activity of N-cadherin and downstream signaling pathways during formation and maturation of cholinergic synapses (Brusés, 2006). "
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    ABSTRACT: N-cadherin is a calcium-sensitive cell adhesion molecule commonly expressed at synaptic junctions and contributes to formation and maturation of synaptic contacts. This study used heterologous cell cultures of brainstem cholinergic neurons and transfected Chinese Hamster Ovary (CHO) cells to examine whether N-cadherin is sufficient to induce differentiation of cholinergic presynaptic terminals. Brainstem nuclei isolated from transgenic mice expressing enhanced green fluorescent protein (EGFP) under the control of choline acetyltransferase (ChAT) transcriptional regulatory elements (ChAT(BAC)EGFP) were cultured as tissue explants for 5 days and cocultured with transfected CHO cells for an additional 2 days. Immunostaining for synaptic vesicle proteins SV2 and synapsin I revealed a ~3-fold increase in the area of SV2 immunolabeling over N-cadherin expressing CHO cells, and this effect was enhanced by coexpression of p120-catenin. Synapsin I immunolabeling per axon length was also increased on N-cadherin expressing CHO cells but required coexpression of p120-catenin. To determine whether N-cadherin induces formation of neurotransmitter release sites, whole-cell voltage-clamp recordings of CHO cells expressing α3 and β4 nicotinic acetylcholine receptor (nAChR) subunits in contact with cholinergic axons were used to monitor excitatory postsynaptic potentials (EPSPs) and miniature EPSPs (mEPSPs). EPSPs and mEPSPs were not detected in both, control and in N-cadherin expressing CHO cells in the absence or presence of tetrodotoxin (TTX). These results indicate that expression of N-cadherin in non-neuronal cells is sufficient to initiate differentiation of presynaptic cholinergic terminals by inducing accumulation of synaptic vesicles; however, development of readily detectable mature cholinergic release sites and/or clustering of postsynaptic nAChR may require expression of additional synaptogenic proteins.
    Frontiers in Synaptic Neuroscience 12/2012; 4:6. DOI:10.3389/fnsyn.2012.00006
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    • "egulating the trafficking and localization of AMPA - type or other glutamate receptor subunits ( Coussen et al . , 2002 ; Nuriya and Huganir , 2006 ; Saglietti et al . , 2007 ; Silverman et al . , 2007 ) ; by affecting presynaptic vesicle release ( Bozdagi et al . , 2004 ; Jungling et al . , 2006 ) or by increasing voltage - gated calcium influx ( Marrs et al . , 2009 ) . Consistent with this idea , it has been shown recently that conditional deletion of N - cadherin at mature synapses impairs persistence of theta - induced LTP and LTP - associated spine enlargement at CA1 synapses ( Bozdagi et al . , 2010 ) , as well as reduces spine stability ( Mendez et al . , 2010 ) ."
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    ABSTRACT: Cadherins are synaptic cell adhesion molecules that contribute to persistently enhanced synaptic strength characteristic of long-term potentiation (LTP). What is relatively unexplored is how synaptic activity of the kind that induces LTP-associated remodeling of synapse structure affects localization of cadherins, particularly in mature animals in vivo, details which could offer insight into how different cadherins contribute to synaptic plasticity. Here, we use a well-described in vivo LTP induction protocol that produces robust synaptic morphological remodeling in dentate gyrus of adult rats in combination with confocal and immunogold electron microscopy to localize cadherin-8 and N-cadherin at remodeled synapses. We find that the density and size of cadherin-8 puncta are significantly diminished in the potentiated middle molecular layer (MML) while concurrently, N-cadherin remains tightly clustered at remodeled synapses. These changes are specific to the potentiated MML, and occur without any change in density or size of synaptophysin puncta. Thus, the loss of cadherin-8 probably represents selective removal from synapses rather than overall loss of synaptic junctions. Together, these findings suggest that activity-regulated loss and retention of different synaptic cadherins could contribute to dual demands of both flexibility and stability in synapse structure that may be important for synaptic morphological remodeling that accompanies long-lasting plasticity.
    Hippocampus 01/2012; 22(1):17-28. DOI:10.1002/hipo.20859 · 4.16 Impact Factor
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