Mechanism of adrenergic CaV1.2 stimulation revealed by proximity proteomics (original) (raw)

Increased cardiac contractility during fight-or-flight response is caused by β-adrenergic augmentation of Ca V 1.2 channels 1-4. In transgenic murine hearts expressing fully PKA phosphorylation-site-deficient mutant Ca V 1.2 α 1C and β subunits, this regulation persists, implying involvement of extra-channel factors. Here, we identify the mechanism by which β-adrenergic agonists stimulate voltage-gated Ca 2+ channels. We expressed α 1C or β 2B subunits conjugated to ascorbate-peroxidase 5 in mouse hearts and used multiplexed, quantitative proteomics 6,7 to track hundreds of proteins in proximity of Ca V 1.2. We observed that the Ca 2+ channel inhibitor Rad 8,9 , a monomeric G-protein, is enriched in the Ca V 1.2 micro-environment but is depleted during β-adrenergic stimulation. PKA-catalyzed phosphorylation of specific Ser residues on Rad decreases its affinity for auxiliary β-Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

Sign up for access to the world's latest research.

checkGet notified about relevant papers

checkSave papers to use in your research

checkJoin the discussion with peers

checkTrack your impact