D2 dopamine receptors interact directly with N-type calcium channels and regulate channel surface expression levels

Abstract

N-type channels are located on dendrites and at pre-synaptic nerve terminals where they play a fundamental role in neurotransmitter release. They are potently regulated by the activation of a number of different types of pertussis toxin (PTX)-sensitive G alpha(i/o) coupled receptors, which results in voltage-dependent inhibition of channel activity via G betagamma subunits. Using heterologous expression in HEK 293T cells, we show via whole cell patch clamp recordings that D2 receptors mediate both G betagamma (i.e., voltage-dependent) and voltage-independent inhibition of channel activity. Furthermore, using co-immunoprecipitation and pull down assays involving the intracellular regions of each protein, we show that D2 receptors and N-type channels form physical signaling complexes. Finally, we use confocal microscopy to demonstrate that D2 receptors regulate N-type channel trafficking to affect the number of calcium channels available at the plasma membrane. Taken together, these data provide evidence for multiple voltage-dependent and voltage-independent mechanisms by which D2 receptor subtypes influence N-type channel activity.

G Protein Regulation of Neuronal Calcium Channels: Back to the Future

“…Similar observations have been reported for m-and d-opioid receptors transiently expressed with Ca v 2.2 channel in tsA201 cells, although the existence of these protein complexes remains to be explored in native conditions (Chee et al, 2008;Evans et al, 2010). Also, a physical interaction exists between Ca v 2.2 channels and dopamine D1 and D2 receptors and requires other channel structural determinants, including the II-III intracellular linker Kisilevsky and Zamponi, 2008;Weiss, 2009). Although the existence of Ca v 2-GPCR signaling complexes is unambiguous, the physiologic relevance of these interactions is not fully understood.…”

The Physiology, Signaling, and Pharmacology of Dopamine Receptors

“…Furthermore, these full-length molecules also interact in native tissue, and the activation of D1 dopamine receptors results in a protein interaction-dependent inhibition/internalization of N-type calcium channels in the prefrontal cortex . A similar interaction of N-type calcium channels with potentially similar effects on the regulation of Ntype calcium channels has also been reported for transfected cells (Kisilevsky and Zamponi, 2008).…”

Regulation of N-type calcium channels by G-proteins: Multiple pathways to control calcium entry into neurons

“…6 In a recent issue of Channels, Kisilevsky and Zamponi extended this study to the D2 dopamine receptor (D2R). 7 They demonstrate that D2R physically associates with N-type Ca 2+ channel allowing Ca 2+ current inhibition in voltage-dependent and voltage-independent manners, but also by controlling channel surface expression level.…”

“…1A from ref. 7). According to the extent of current recovery assessed by strong membrane depolarizing prepulse, the authors propose that activation of D2Rs produces both voltage-dependent (i.e.…”