Mechanisms and functions of AT1 angiotensin receptor internalization

Hunyady, László; Catt, Kevin J.; Clark, Adrian J. L.; Gáborik, Zsuzsanna

doi:10.1016/s0167-0115(00)00137-3

Cited by 127 publications

(126 citation statements)

References 177 publications

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“…Our results show that CHO-K1 cells stably transfected with the Flag-tagged angiotensin II receptor bind angiotensin II with an affinity similar to that of cells expressing the wild-type AT 1 , confirming that the modified receptor is properly expressed in the cell membrane (3).…”

Section: Discussionsupporting

confidence: 65%

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Ligand-induced endocytosis and nuclear localization of angiotensin II receptors expressed in CHO cells

Merjan

Kanashiro

Krieger

et al. 2001

Braz J Med Biol Res

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A construct (AT1R-NF) containing a "Flag" sequence added to the Nterminus of the rat AT 1 receptor was stably expressed in Chinese hamster ovary cells and quantified in the cell membrane by confocal microscopy after reaction with a fluorescein-labeled anti-Flag monoclonal antibody. Angiotensin II bound to AT1R-NF and induced endocytosis with a half-time of 2 min. After 60-90 min, fluorescence accumulated around the cell nucleus, suggesting migration of the ligand-receptor complex to the nuclear membrane. Angiotensin antagonists also induced endocytosis, suggesting that a common step in the transduction signal mechanism occurring after ligand binding may be responsible for the ligand-receptor complex internalization. Correspondence

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Section: Discussionsupporting

confidence: 65%

“…3) and processing of the ligand-receptor complex which occurs in endosomes, part of the receptors being returned to the plasma membrane (4). Internalization and recycling are important factors in determining the number of free receptors on the cell surface available for interaction with the ligand (5).…”

Section: Introductionmentioning

confidence: 99%

Ligand-induced endocytosis and nuclear localization of angiotensin II receptors expressed in CHO cells

Merjan

Kanashiro

Krieger

et al. 2001

Braz J Med Biol Res

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“…Although it was proven for numerous neuropeptides both in cell cultures in vitro and in whole organs in vivo that they are incorporated into their target cells after binding to their cell membrane receptors [23,28], the meaning of this process often remains unclear. As for NPY, further studies must examine how NPY is internalized, what happens to the ligand-receptor complex after internalization, whether both are degraded, or whether the receptor is retransported to the plasma membrane, and finally the meaning of the partial internalization that was proven at this cell.…”

Section: Discussionmentioning

confidence: 99%

Monitoring of the internalization of neuropeptide Y on neuroblastoma cell line SK‐N‐MC

Fabry

Langer

Rothen‐Rutishauser

et al. 2000

European Journal of Biochemistry

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Neuropeptide Y (NPY) is an important neuromodulator in the central and peripheral nervous system. The peptide acts through different NPY receptor subtypes (Y1±Y5, y6) that belong to the family of G protein-coupled receptors. In general, cellular responses to prolonged exposure to agonists of G protein-coupled receptors are attenuated, often through internalization of the receptors and their bound ligands. In this study, a fluorescent labeled NPY derivative was synthesized and characterized to investigate the internalization of NPY in the human neuroblastoma cell line SK-N-MC. Internalization was proven by binding experiments and subsequent acidic washing as well as by direct visualization by means of confocal laser scanning microscopy. Approximately 20±30% of the fluorescent labeled NPY and a tritium-marked NPY were resistant to acid removal of cell surfacebound ligands indicating internalization. Extracellular fluorescent labeled NPY was found to be distributed heterogeneously in a clustered pattern, which suggests that the ligand-receptor complex is collected in pits and caveolae followed by endocytosis. Keywords: neuropeptide Y (NPY); internalization; neuroblastoma cells; fluorescent labeling.Neuropeptide Y (NPY) is a neurotransmitter consisting of 36 amino acids that belongs to the family of pancreatic polypeptides. These polypeptides are important modulators of the central and peripheral nervous system and NPY is one of the most abundant neuropeptides in the brain. NPY acts peripherally as a vasoconstrictor and modulates the activity of further neurotransmitters. Centrally, NPY is involved in the stimulating of food intake, memory retention and anxiolysis. So far, five receptor subtypes (Y1, Y2, Y4, Y5, y6) were identified that bind NPY with nanomolar affinity [1]. They all belong to the large family of G protein-coupled receptors (GPCR) with their typical seven-transmembrane helix structure [2].Approximately 80% of all bioactive molecules, especially hormones and neurotransmitters, act through the interaction of GPCR that transduce extracellular signals to the interior of cells. Signaling through these receptors, however, is rapidly desensitized primarily as a consequence of receptor phosphorylation, but internalization and receptor downregulation have also been shown to occur [3]. Many GPCR are known to internalize after agonist binding, however, the conditions for this mechanism and its importance for the desensitization and resensitization as well as for the fate of receptor and ligand within the cells are different and often unclear.Regulatory mechanisms of signal attenuation, including the removal of the ligands from the extracellular space by enzymatic degradation, are important to ensure the ability of the cells to react to the agonists. Degradation of the peptide and desensitization of the NPY signal have been reported [4,5]. Recently, investigations showed that CHO cells expressing the Y4 receptor were resistant to agonist-promoted desensitization and internalization [6].In the present study, we e...

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“…The AT1R at the plasma membrane undergoes internalization in the continuous presence of the agonist Ang II. The internalized AT1R may then be transported to the lysosome for degradation or recycled back to the plasma membrane (15)(16)(17)(18)(19). Therefore, the number of AT1Rs at the plasma membrane is determined by the overall balance of AT1R export to the cell surface, internalization, recycling, and degradation.…”

Section: Rab1mentioning

confidence: 99%

“…Therefore, the number of AT1Rs at the plasma membrane is determined by the overall balance of AT1R export to the cell surface, internalization, recycling, and degradation. Although most studies on AT1R trafficking have focused on the events involved in the internalization, recycling, and degradation (15)(16)(17)(18)(19), the export of AT1R from the ER through the Golgi to the cell surface and regulation of receptor function by these processes remain poorly understood.…”

Section: Rab1mentioning

confidence: 99%

Regulation of the Cell Surface Expression and Function of Angiotensin II Type 1 Receptor by Rab1-mediated Endoplasmic Reticulum-to-Golgi Transport in Cardiac Myocytes

Filipeanu¹,

Zhou²,

Claycomb

et al. 2004

Journal of Biological Chemistry

106

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Rab1GTPase coordinates vesicle-mediated protein transport specifically from the endoplasmic reticulum (ER) to the Golgi apparatus. We recently demonstrated that Rab1 is involved in the export of angiotensin II (Ang II) type 1 receptor (AT1R) to the cell surface in HEK293 cells and that transgenic mice overexpressing Rab1 in the myocardium develop cardiac hypertrophy. To expand these studies, we determined in this report whether the modification of Rab1-mediated ER-to-Golgi transport can alter the cell surface expression and function of endogenous AT1R and AT1R-mediated hypertrophic growth in primary cultures of neonatal rat ventricular myocytes. Adenovirus-mediated gene transfer of wild-type Rab1 (Rab1WT) significantly increased cell surface expression of endogenous AT1R in neonatal cardiomyocytes, whereas the dominant-negative mutant Rab1N124I had the opposite effect. Brefeldin A treatment blocked the Rab1WT-induced increase in AT1R cell surface expression. Fluorescence analysis of the subcellular localization of AT1R revealed that Rab1 regulated AT1R transport specifically from the ER to the Golgi in HL-1 cardiomyocytes. Consistent with their effects on AT1R export, Rab1WT and Rab1N124I differentially modified the AT1R-mediated activation of ERK1/2 and its upstream kinase MEK1. More importantly, adenovirus-mediated expression of Rab1N124I markedly attenuated the Ang II-stimulated hypertrophic growth as measured by protein synthesis, cell size, and sarcomeric organization in neonatal cardiomyocytes. In contrast, Rab1WT expression augmented the Ang II-mediated hypertrophic response. These data strongly indicate that AT1R function in cardiomyocytes can be modulated through manipulating AT1R traffic from the ER to the Golgi and provide the first evidence implicating the ERto-Golgi transport as a regulatory site for control of cardiomyocyte growth.

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Mechanisms and functions of AT1 angiotensin receptor internalization

Cited by 127 publications

References 177 publications

Ligand-induced endocytosis and nuclear localization of angiotensin II receptors expressed in CHO cells

Ligand-induced endocytosis and nuclear localization of angiotensin II receptors expressed in CHO cells

Monitoring of the internalization of neuropeptide Y on neuroblastoma cell line SK‐N‐MC

Regulation of the Cell Surface Expression and Function of Angiotensin II Type 1 Receptor by Rab1-mediated Endoplasmic Reticulum-to-Golgi Transport in Cardiac Myocytes

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