In-vivophosphorylation of the cardiac L-type calcium channel beta-subunit in response to catecholamines

✍ Scribed by Hannelore Haase; Sabine Bartel; Peter Karczewski; Ingo Morano; Ernst-Georg Krause

• Book ID: 104761709
• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 654 KB
• Volume: 163-164
• Category: Article
• ISSN: 0300-8177
• DOI: 10.1007/bf00408645

✦ Synopsis

In canine myocardium, the [3-subunit of the L-type Ca 2+ channel is phosphorylated by cAMP dependent protein kinase in vitro as well as in vivo (Haase et al. FEBS Lett 335: 217-222, 1993). We have assessed the identity of the J3-subunit as well as its in vivo phosphorylation in representative experimental groups of catecholamine-challenged canine hearts. Adrenergic stimulation by high doses of both noradrenaline and isoprenaline induced rapid (within 20 sec) and nearly complete phosphorylation of the Ca 2÷ channel [3-subunit. Phosphorylation in vivo was about 4-fold higher as compared to untreated controls. When related to catecholamine-depleted (reserpine-treated) hearts noradrenaline and isoprenaline increased the in vivo phosphorylation of the j3-subunit even 8-fold. This phosphorylation correlated positively with tissue levels of cAMP, endogenous particulated cAMP-dependent protein kinase (PKA) and the rate of contractile force development dP/dtma x. The results imply the involvement of a PKA-mediated phosphorylation of the Ca 2+ channel [3-subunit in the adrenergic stimulation of intact canine myocardium. (Mol Cell Biochem 163/164: 99-106, 1996)