Dataset Information

Adenylyl cyclase subtype-specific compartmentalization: differential regulation of L-type Ca2+ current in ventricular myocytes.

ABSTRACT: Adenylyl cyclase (AC) represents one of the principal molecules in the ?-adrenergic receptor signaling pathway, responsible for the conversion of ATP to the second messenger, cAMP. AC types 5 (ACV) and 6 (ACVI) are the 2 main isoforms in the heart. Although highly homologous in sequence, these 2 proteins play different roles during the development of heart failure. Caveolin-3 is a scaffolding protein, integrating many intracellular signaling molecules in specialized areas called caveolae. In cardiomyocytes, caveolin is located predominantly along invaginations of the cell membrane known as t-tubules.We take advantage of ACV and ACVI knockout mouse models to test the hypothesis that there is distinct compartmentalization of these isoforms in ventricular myocytes.We demonstrate that ACV and ACVI isoforms exhibit distinct subcellular localization. The ACVI isoform is localized in the plasma membrane outside the t-tubular region and is responsible for ?1-adrenergic receptor signaling-mediated enhancement of the L-type Ca(2+) current (ICa,L) in ventricular myocytes. In contrast, the ACV isoform is localized mainly in the t-tubular region where its influence on ICa,L is restricted by phosphodiesterase. We further demonstrate that the interaction between caveolin-3 with ACV and phosphodiesterase is responsible for the compartmentalization of ACV signaling.Our results provide new insights into the compartmentalization of the 2 AC isoforms in the regulation of ICa,L in ventricular myocytes. Because caveolae are found in most mammalian cells, the mechanism of ?- adrenergic receptor and AC compartmentalization may also be important for ?-adrenergic receptor signaling in other cell types.

SUBMITTER: Timofeyev V

PROVIDER: S-EPMC3751398 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Adenylyl cyclase subtype-specific compartmentalization: differential regulation of L-type Ca2+ current in ventricular myocytes.

Timofeyev Valeriy V Myers Richard E RE Kim Hyo Jeong HJ Woltz Ryan L RL Sirish Padmini P Heiserman James P JP Li Ning N Singapuri Anil A Tang Tong T Yarov-Yarovoy Vladimir V Yamoah Ebenezer N EN Hammond H Kirk HK Chiamvimonvat Nipavan N

Circulation research 20130422 12

<h4>Rationale</h4>Adenylyl cyclase (AC) represents one of the principal molecules in the β-adrenergic receptor signaling pathway, responsible for the conversion of ATP to the second messenger, cAMP. AC types 5 (ACV) and 6 (ACVI) are the 2 main isoforms in the heart. Although highly homologous in sequence, these 2 proteins play different roles during the development of heart failure. Caveolin-3 is a scaffolding protein, integrating many intracellular signaling molecules in specialized areas calle ...[more]

PMID: 23609114

Similar Datasets

Project description:The effects of several phosphodiesterase (PDE) inhibitors on the L-type Ca current (I(Ca)) and intracellular cyclic AMP concentration ([cAMP]i) were examined in isolated rat ventricular myocytes. The presence of mRNA transcripts encoding for the different cardiac PDE subtypes was confirmed by RT-PCR. IBMX (100 microM), a broad-spectrum PDE inhibitor, increased basal I(Ca) by 120% and [cAMP]i by 70%, similarly to a saturating concentration of the beta-adrenoceptor agonist isoprenaline (1 microM). However, MIMX (1 microM), a PDE1 inhibitor, EHNA (10 microM), a PDE2 inhibitor, cilostamide (0.1 microM), a PDE3 inhibitor, or Ro20-1724 (0.1 microM), a PDE4 inhibitor, had no effect on basal I(Ca) and little stimulatory effects on [cAMP]i (20-30%). Each selective PDE inhibitor was then tested in the presence of another inhibitor to examine whether a concomitant inhibition of two PDE subtypes had any effect on I(Ca) or [cAMP]i. While all combinations tested significantly increased [cAMP]i (40-50%), only cilostamide (0.1 microM)+ Ro20-1724 (0.1 microM) produced a significant stimulation of I(Ca) (50%). Addition of EHNA (10 microM) to this mix increased I(Ca) to 110% and [cAMP]i to 70% above basal, i.e. to similar levels as obtained with IBMX (100 microM) or isoprenaline (1 microM). When tested on top of a sub-maximal concentration of isoprenaline (1 nM), which increased I(Ca) by (approximately 40% and had negligible effect on [cAMP]i, each selective PDE inhibitor induced a clear stimulation of [cAMP]i and an additional increase in I(Ca). Maximal effects on I(Ca) were approximately 8% for MIMX (3 microM), approximately 20% for EHNA (1-3 microM), approximately 30% for cilostamide (0.3-1 microM) and approximately 50% for Ro20-1724 (0.1 microM). Our results demonstrate that PDE1-4 subtypes regulate I(Ca) in rat ventricular myocytes. While PDE3 and PDE4 are the dominant PDE subtypes involved in the regulation of basal I(Ca), all four PDE subtypes determine the response of I(Ca) to a stimulus activating cyclic AMP production, with the rank order of potency PDE4>PDE3>PDE2>PDE1.

Dataset Information

Adenylyl cyclase subtype-specific compartmentalization: differential regulation of L-type Ca2+ current in ventricular myocytes.

Publications

Adenylyl cyclase subtype-specific compartmentalization: differential regulation of L-type Ca2+ current in ventricular myocytes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets