What question did this study set out to answer?

To determine whether two different size forms of L-type calcium channel alpha 1 subunits undergo basal and cyclic AMP-dependent phosphorylation in intact skeletal muscle cells.

December 1, 1990Journal of Biological ChemistryOpen Access

Cyclic AMP-dependent phosphorylation of two size forms of alpha 1 subunits of L-type calcium channels in rat skeletal muscle cells.

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To determine whether two different size forms of L-type calcium channel alpha 1 subunits undergo basal and cyclic AMP-dependent phosphorylation in intact skeletal muscle cells.
Cultured rat skeletal muscle cells were lysed under conditions inhibiting proteolysis and dephosphorylation, followed by alpha 1 subunit isolation via monoclonal antibody immunoprecipitation.
Identified and analyzed 200 kDa and 160 kDa subunits through in vitro back phosphorylation with cAMP-dependent protein kinase, phosphopeptide mapping, and metabolic 32P labeling after treatment with forskolin, isoproterenol, CGRP, or 8-bromo-cAMP.
Two alpha 1 subunit variants (200 kDa and 160 kDa) exhibited basal phosphorylation levels of 35% to 40%, which rose to 83% to 86% following cAMP stimulation.
Treatment with forskolin, isoproterenol, CGRP, or 8-bromo-cAMP reduced in vitro 32P back phosphorylation by 60% to 80% across all phosphopeptides, confirming near-maximal endogenous phosphorylation of both subunits.
Metabolic labeling demonstrated incorporation of 3 mol of phosphate per alpha 1 subunit under basal conditions, with forskolin stimulating 32P incorporation by 1.6-fold.

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Implication

Experimental cell study demonstrates dual-sized alpha 1 subunits undergo basal and stimulated cAMP phosphorylation in rat muscle cells, indicating dynamic regulation of calcium channels.

Cite This Study

Lai et al. (1990) studied this question.

synapsesocial.com/papers/6a7005db2163a0a01bc43ea4 https://doi.org/10.1016/s0021-9258(17)45292-6

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Implication

Experimental cell study demonstrates dual-sized alpha 1 subunits undergo basal and stimulated cAMP phosphorylation in rat muscle cells, indicating dynamic regulation of calcium channels.

Cyclic AMP-dependent phosphorylation of two size forms of alpha 1 subunits of L-type calcium channels in rat skeletal muscle cells.

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Discussion

Implication

Cite This Study

Cyclic AMP-dependent phosphorylation of two size forms of alpha 1 subunits of L-type calcium channels in rat skeletal muscle cells.

Key Points

Discussion

Implication

Cite This Study

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