Evidence for cardiac sodium–calcium exchanger association with caveolin‐3

Bossuyt, Julie; Taylor, Bonnie E.; James-Kracke, Marilyn R.; Hale, Calvin C.

doi:10.1016/s0014-5793(01)03323-3

Cited by 58 publications

(47 citation statements)

References 16 publications

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“…With the apparently more selective Triton X-100 method, NCX1 remained in the higher density fractions while the DHPR fractionated to the lighter fractions. Importantly, this demonstrates that NCX1 is not localized to lipid rafts as previously reported [6] and suggests that the DHPR is localized to lipid rafts. Similar data were obtained when the detergent-to-protein ration was either decreased or increased by two-fold (data not shown) indicating that we were not using an inappropriate concentration of detergent.…”

Section: Lipid Raft Isolationsupporting

confidence: 76%

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Localization of sarcolemmal proteins to lipid rafts in the myocardium

et al. 2007

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The localization of sarcolemmal proteins within the membrane can have a dramatic effect on excitation-contraction coupling. We examine the localization of the Na + -Ca 2+ exchanger, the dihydropyridine receptor, and other proteins involved in excitation-contraction coupling in rat heart using biochemical and immunolocalization techniques. Specifically, we assess the distribution of proteins within the lipid raft fraction of the sarcolemma. We find that the distribution of proteins in lipid raft fractions is very dependent on the solubilization technique. A common technique using sodium carbonate/pH 11 to solubilize non-lipid raft proteins was inappropriate for use with sarcolemmal membranes. Use of Triton X-100 was more efficacious as a solubilization agent. A large majority of the Na + -Ca 2+ exchanger, Na + /K + -ATPase, and plasma membrane Ca 2+ pump are not present in lipid rafts. In contrast, most adenosine A 1 receptors and dihydropyridine receptors were in lipid raft fractions. Most of the adenosine A 1 receptors could be co-immunoprecipitated with caveolin indicating a localization to caveolae (a subclass of lipid rafts). In contrast, the dihydropyridine receptors could not be co-immunoprecipitated with caveolin. Most biochemical data were confirmed by high resolution immunolocalization studies. Using correlation analysis, only a small fraction of the Na + -Ca 2+ exchangers colocalized with caveolin whereas a substantial fraction of dihydropyridine and adenosine A 1 receptors did colocalize with caveolin. The most pertinent findings are that the Na + -Ca 2+ exchanger and the dihydropyridine receptor are in separate sarcolemmal subcompartments. These spatial relationships may be relevant for understanding excitation-contraction coupling.

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Section: Lipid Raft Isolationsupporting

confidence: 76%

“…It has recently been suggested, based on biochemical methods, that NCX1 is localized to caveolae and specifically associates with caveolin-3, the main caveolin isoform of cardiomyoctes [6]. Because of the potential importance of this finding in understanding EC coupling, we re-investigated the membrane localization of NCX1.…”

Section: Introductionmentioning

confidence: 99%

Localization of sarcolemmal proteins to lipid rafts in the myocardium

et al. 2007

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“…The activities of many ion channels and transporters are modulated by binding to PI(4,5)P 2 (42) and, interestingly, many of them are concentrated in caveolae (43)(44)(45)(46)(47)(48)(49). The sequential down-and upregulation in the noncaveolar and caveolar membranes may generate specific signals at the cell surface.…”

Section: Discussionmentioning

confidence: 99%

A distinct pool of phosphatidylinositol 4,5-bisphosphate in caveolae revealed by a nanoscale labeling technique

Fujita

Cheng

Tauchi-Sato

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

178

159

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Fig. 1. Labeling of the liposome. (A)Outline of the method. Cells were rapidly frozen, freeze-fractured, and evaporated with carbon (C) and platinum/carbon (Pt/C) in vacuum. The replica of the split membrane was digested with SDS to remove noncast molecules and labeled by GST-PH. Both the cytoplasmic and exoplasmic halves of the membrane were examined. (B) Labeling of small unilamellar liposome replicas. Freeze-fracture replicas of liposomes containing 95 mol % of phosphatidylcholine (PC) and 5 mol % of phosphatidylinositol or a phosphoinositide were labeled. Only liposomes containing PI(4,5)P 2 were labeled intensely by GST-PH. A PH mutant, GST-PH (K30N, K32N), which does not bind PI(4,5)P 2, showed little labeling in the PI(4,5)P 2-containing liposome. (C) Quantification of the GST-PH labeling in the liposomes. The number of gold particles per 1 m 2 of the liposome surface is shown (blue). The labeling on the convex (green) and concave (yellow) surfaces showed equivalent results.

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“…2, have not been determined, but the ion exchangers' vesicular localizations and their transport to the cell membrane are associated with the lipid raft microdomain (Fig. 5, a and b) (43,45,46). It is generally accepted, despite a lack of mechanistic description, that integrity of the lipid raft is essential for many functions downstream of integrin signaling (33), including calcium mobilization (47) and thrombosis (35).…”

Section: And 5)mentioning

confidence: 99%

Membrane Targeting and Coupling of NHE1-IntegrinαIIbβ3-NCX1 by Lipid Rafts following Integrin-Ligand Interactions Trigger Ca2+ Oscillations

Yi¹,

Ho²,

Chen³

et al. 2009

Journal of Biological Chemistry

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The cyclic calcium release and uptake during calcium oscillation are thought to result from calcium-induced calcium release (CICR); however, it is unclear, especially in nonexcitable cells, how the initial calcium mobilization that triggers CICR occurs. We report here a novel mechanism, other than conventional calcium channels or the phopholipase C-inositol trisphosphate system, for initiating calcium oscillation downstream of integrin signaling. Upon integrin ␣ IIb ␤ 3 binding to fibrinogen ligand or the disintegrin rhodostomin, sodium-proton exchanger NHE1 and sodiumcalcium exchanger NCX1 are actively transported to the plasma membrane, and they become physically coupled to integrin ␣ IIb ␤ 3 . Lipid raft-dependent mechanisms modulate the membrane targeting and formation of the NHE1-integrin ␣ IIb ␤ 3 -NCX1 protein complex. NHE1 and NCX1 within such protein complex are functionally coupled, such that a local increase of sodium concentration caused by NHE1 can drive NCX1 to generate sodium efflux in exchange for calcium influx. The resulting calcium increase inside the cell can then trigger CICR as a prelude to calcium oscillation downstream of integrin ␣ IIb ␤ 3 signaling. Fluorescence resonance energy transfer based on fluorescence lifetime measurements is employed here to monitor the intermolecular interactions among NHE1-integrin ␣ IIb ␤ 3 -NCX1, which could not be properly detected using conventional biochemical assays.In many excitable or nonexcitable cells, the concentration of free intracellular calcium oscillates with a period ranging from a few seconds to a few minutes. Such calcium oscillations are involved in a wide variety of cellular functions (1, 2). It is generally believed that, except for minor variations, the cyclic increase and decrease of calcium results from an autocatalytic release of calcium in a process called calcium-induced calcium release (CICR), 2 followed by a slow negative feedback that terminates calcium release. The cytoplasmic free calcium is then taken up into the organelles to reset the cycle. Despite a general agreement on how calcium oscillation proceeds once the system has been turned on, various different mechanisms have been proposed to explain how the initial calcium mobilization is generated that triggers CICR.As a general rule, calcium entry through voltage-gated channels in electrically excitable cells (3) or through agonist-receptor interactions in nonexcitable cells, such as epithelial cells, hepatocytes, or oocytes (4), is thought to initiate the CICR process (1, 2). Typically, in nonexcitable cells, the binding of an agonist, such as a hormone, a growth factor, or an extracellular matrix, to the corresponding cell surface receptor initiates a series of reactions that end in the activation of phopholipase C (PLC) and the production of the secondary messenger inositol trisphosphate (IP 3 ) (1, 2, 4). IP 3 is thought to induce calcium release from the internal endoplasmic reticulum or mitochondria store, and governs the CICR mechanisms that modulate calcium oscillat...

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Evidence for cardiac sodium–calcium exchanger association with caveolin‐3

Cited by 58 publications

References 16 publications

Localization of sarcolemmal proteins to lipid rafts in the myocardium

Localization of sarcolemmal proteins to lipid rafts in the myocardium

A distinct pool of phosphatidylinositol 4,5-bisphosphate in caveolae revealed by a nanoscale labeling technique

Membrane Targeting and Coupling of NHE1-IntegrinαIIbβ3-NCX1 by Lipid Rafts following Integrin-Ligand Interactions Trigger Ca2+ Oscillations

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