G Protein-induced Trafficking of Voltage-dependent Calcium Channels

Eugene Tombler,Nory Jun Cabanilla,Paul Carman,Natasha Permaul,John J Hall,Ryan W Richman,Jessica Lee,Jennifer Rodriguez,Dan P Felsenfeld,Robert F Hennigan,María A Diversé-Pierluissi

doi:10.1074/jbc.m508829200

Eugene Tombler, Nory Jun Cabanilla + Show 9 more

Open Access

https://doi.org/10.1074/jbc.m508829200

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Abstract

Calcium channels are well known targets for inhibition by G protein-coupled receptors, and multiple forms of inhibition have been described. Here we report a novel mechanism for G protein-mediated modulation of neuronal voltage-dependent calcium channels that involves the destabilization and subsequent removal of calcium channels from the plasma membrane. Imaging experiments in living sensory neurons show that, within seconds of receptor activation, calcium channels are cleared from the membrane and sequestered in clathrin-coated vesicles. Disruption of the L1-CAM-ankyrin B complex with the calcium channel mimics transmitter-induced trafficking of the channels, reduces calcium influx, and decreases exocytosis. Our results suggest that G protein-induced removal of plasma membrane calcium channels is a consequence of disrupting channel-cytoskeleton interactions and might represent a novel mechanism of presynaptic inhibition.

Highlights

From the Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029
Calcium channels are well known targets for inhibition by G pro- this study we have found that activation of G protein-coupled receptors tein-coupled receptors, and multiple forms of inhibition have been induces destabilization and subsequent removal of calcium channels described
Our results suggest that G protein-induced removal of plasma membrane calcium channels is a consequence of disrupting channel-cytoskeleton interactions and might represent a

Summary

Introduction

In membrane parallels the time course of transmitter-mediated inhibition experiments in which the transmitter was applied for a 20-s interval of calcium current and desensitization of the response, respectively, followed by a washout with saline, the fluorescence signal reappeared to suggesting that channel trafficking might provide a mechanism to modthe cell surface within 10 s (see Fig. 5d, control). Gi/o Mediates Removal of Cav2.2 Channels—Transmitter-induced slices, and the channels appear not to be membrane-associated (Fig. 2, a inhibition of voltage-dependent calcium channels is mediated through and b).

Results

Conclusion