Back to Search
Start Over
Identification of caveolar resident proteins in ventricular myocytes using a quantitative proteomic approach: dynamic changes in caveolar composition following adrenoceptor activation.
- Source :
-
Molecular & cellular proteomics : MCP [Mol Cell Proteomics] 2015 Mar; Vol. 14 (3), pp. 596-608. Date of Electronic Publication: 2015 Jan 05. - Publication Year :
- 2015
-
Abstract
- The lipid raft concept proposes that membrane environments enriched in cholesterol and sphingolipids cluster certain proteins and form platforms to integrate cell signaling. In cardiac muscle, caveolae concentrate signaling molecules and ion transporters, and play a vital role in adrenergic regulation of excitation-contraction coupling, and consequently cardiac contractility. Proteomic analysis of cardiac caveolae is hampered by the presence of contaminants that have sometimes, erroneously, been proposed to be resident in these domains. Here we present the first unbiased analysis of the proteome of cardiac caveolae, and investigate dynamic changes in their protein constituents following adrenoreceptor (AR) stimulation. Rat ventricular myocytes were treated with methyl-β-cyclodextrin (MβCD) to deplete cholesterol and disrupt caveolae. Buoyant caveolin-enriched microdomains (BCEMs) were prepared from MβCD-treated and control cell lysates using a standard discontinuous sucrose gradient. BCEMs were harvested, pelleted, and resolubilized, then alkylated, digested, and labeled with iTRAQ reagents, and proteins identified by LC-MS/MS on a LTQ Orbitrap Velos Pro. Proteins were defined as BCEM resident if they were consistently depleted from the BCEM fraction following MβCD treatment. Selective activation of α-, β1-, and β2-AR prior to preparation of BCEMs was achieved by application of agonist/antagonist pairs for 10 min in populations of field-stimulated myocytes. We typically identified 600-850 proteins per experiment, of which, 249 were defined as high-confidence BCEM residents. Functional annotation clustering indicates cardiac BCEMs are enriched in integrin signaling, guanine nucleotide binding, ion transport, and insulin signaling clusters. Proteins possessing a caveolin binding motif were poorly enriched in BCEMs, suggesting this is not the only mechanism that targets proteins to caveolae. With the notable exception of the cavin family, very few proteins show altered abundance in BCEMs following AR activation, suggesting signaling complexes are preformed in BCEMs to ensure a rapid and high fidelity response to adrenergic stimulation in cardiac muscle.<br /> (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Subjects :
- Adrenergic Antagonists pharmacology
Animals
Gene Expression Regulation drug effects
Mice
Myocytes, Cardiac cytology
Myocytes, Cardiac metabolism
Rats
Signal Transduction
beta-Cyclodextrins pharmacology
Adrenergic Agonists pharmacology
Caveolae metabolism
Myocytes, Cardiac drug effects
Proteome isolation & purification
Proteomics methods
Subjects
Details
- Language :
- English
- ISSN :
- 1535-9484
- Volume :
- 14
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Molecular & cellular proteomics : MCP
- Publication Type :
- Academic Journal
- Accession number :
- 25561500
- Full Text :
- https://doi.org/10.1074/mcp.M114.038570