Histamine H2 Receptor Desensitization: Involvement of a Select Array of G Protein-Coupled Receptor Kinases

Shayo, Carina; Fernández, Natalia Cristina; Legnazzi, Bibiana Lemos; Monczor, Federico; Mladovan, Alejandro; Baldi, Alberto; Davio, Carlos

doi:10.1124/mol.60.5.1049

Cited by 45 publications

(49 citation statements)

References 35 publications

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“…We have reported previously that H2r exposure to amthamine induces a rapid and homologous desensitization (Lemos Legnazzi et al, 2000;Shayo et al, 2001). In the present study, we found that H2r internalized after agonist exposure and that the loss of cAMP response was observed earlier than that of H2r membrane sites (Fig.…”

Section: Discussionsupporting

confidence: 71%

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Histamine H2 Receptor Trafficking: Role of Arrestin, Dynamin, and Clathrin in Histamine H2 Receptor Internalization

Fernández¹,

Monczor²,

Baldi³

et al. 2008

Mol Pharmacol

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Agonist-induced internalization of G protein-coupled receptors (GPCRs) has been implicated in receptor desensitization, resensitization, and down-regulation. In the present study, we sought to establish whether the histamine H2 receptor (H2r) agonist amthamine, besides promoting receptor desensitization, induced H2r internalization. We further studied the mechanisms involved and its potential role in receptor resensitization. In COS7 transfected cells, amthamine induced H2r time-dependent internalization, showing 70% of receptor endocytosis after 60-min exposure to amthamine. Agonist removal led to the rapid recovery of resensitized receptors to the cell surface. Similar results were obtained in the presence of cycloheximide, an inhibitor of protein synthesis. Treatment with okadaic acid, an inhibitor of the protein phosphatase 2A (PP2A) family of phosphatases, reduced the recovery of both H2r membrane sites and cAMP response. Arrestin 3 but not arrestin 2 overexpression reduced both H2r membrane sites and H2r-evoked cAMP response. Receptor cotransfection with dominant-negative mutants for arrestin, dynamin, Eps15 (a component of the clathrin-mediated endocytosis machinery), or RNA interference against arrestin 3 abolished both H2r internalization and resensitization. Similar results were obtained in U937 cells endogenously expressing H2r. Our findings suggest that amthamine-induced H2r internalization is crucial for H2r resensitization, processes independent of H2r de novo synthesis but dependent on PP2A-mediated dephosphorylation. Although we do not provide direct evidence for H2r interaction with ␤-arrestin, dynamin, and/or clathrin, our results support their involvement in H2r endocytosis. The rapid receptor recycling to the cell surface and the specific involvement of arrestin 3 in receptor internalization further suggest that the H2r belongs to class A GPCRs.

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Section: Discussionsupporting

confidence: 71%

“…We reported previously that a rapid homologous desensitization of the H2r is observed in transfected COS7 cells and U937 cells (Lemos Legnazzi et al, 2000;Shayo et al, 2001). In addition, Smit and coworkers (1995) showed the loss of H2r membrane immunofluorescence after 1-h exposure to histamine.…”

Section: Resultsmentioning

confidence: 99%

Histamine H2 Receptor Trafficking: Role of Arrestin, Dynamin, and Clathrin in Histamine H2 Receptor Internalization

Fernández¹,

Monczor²,

Baldi³

et al. 2008

Mol Pharmacol

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“…This phenomenon could have serious physiological implications because it was observed not only in genetically manipulated systems, but also with endogenously expressed receptors. (16).…”

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confidence: 99%

Expression of a G Protein-coupled Receptor (GPCR) Leads to Attenuation of Signaling by Other GPCRs

Tubio

Fernández

Fitzsimons

et al. 2010

Journal of Biological Chemistry

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The idea of G protein-coupled receptors (GPCRs) coupling to G protein solely in their active form was abolished when it was found that certain ligands induce a G protein-coupled but inactive receptor form. This receptor form interferes with signaling of other receptors by sequestering G protein. However, the spontaneous existence of this receptor species has never been established. The aim of the present work was to evaluate the existence of the spontaneous conformation of the receptor inactively coupled to G protein able to interfere with the response of other GPCRs. According to the law of mass action, receptor overexpression should lead to increased amounts of all spontaneously occurring species. Based on this, we generated Chinese hamster ovary (CHO-K1)-derived cell lines expressing various amounts of the human histamine H2 receptor. In these systems, the signaling of other endogenously and transiently expressed GPCRs was attenuated proportionally to human H2 receptor expression levels. G protein transfection specifically reverted this attenuation, strongly suggesting hijacking of the G protein from a common pool. Similar attenuation effects were observed when the ␤ 2 -adrenergic receptor was overexpressed, suggesting that this is a more general phenomenon. Moreover, in human mammary MDA-MB-231 cells, a consistent increase in the response of other GPCRs was observed when endogenous expression of ␤ 2 -adrenergic receptor was knocked down using specific small interfering RNAs. Our findings show that GPCRs may interact with the signaling of other receptors by modulating the availability of the G protein and suggest the existence of GPCR spontaneous coupling to G proteins in an inactive form. G protein-coupled receptors (GPCRs)2 form a large and functionally diverse superfamily of proteins that transduce signals across cell membranes. Although much is known about structural features of GPCRs involved in ligand recognition and G protein binding, the actual mechanism underlying GPCR signaling remains unclear.Traditionally, agonist occupancy of GPCRs is believed to result in a conformational change in the receptor, leading to activation of G proteins (1). However, in genetically engineered systems where receptors can be expressed at high densities, Costa and Herz (2) noted that high levels of receptor expression uncovered the existence of a population of spontaneously (unliganded) active receptors, resulting in an elevated basal response in the system.The histamine H2 receptor (H2R) is an extensively characterized member of the GPCR family, which in most systems couples to G s proteins to activate adenylyl cyclase (3-6). Compared with other GPCRs, the H2R is unique in that the wildtype receptor possesses a remarkably high degree of constitutive activity. With a receptor density of 300 fmol/mg protein, constitutive H2 receptor activity could be detected in Chinese hamster ovary (CHO-K1) cells (7).The notion that GPCRs also signal without an external chemical trigger, i.e. in a constitutive or spontaneous manner, res...

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“…There are potential phosphorylation sites in the third intracellular loop and in the carboxy-terminal tail of the H 2 receptor. The H 2 receptor mutant that lacks most of serine / threonine residues in the C-terminus can still be affected by GRK2 and GRK3, suggesting that the C-terminus is not involved in the GRK mediated desensitization of the histamine H 2 receptor (21,22). Further study is needed to clarify the receptor region responsible for the GRKmediated desensitization.…”

Section: Roles Of C-terminal Tails Of Histamine Receptorsmentioning

confidence: 99%

“…When co-expressed with H 2 receptor in COS-7 cells, G-protein-coupled receptor kinases (GRKs) 2 and 3 (also called βARK 1 and 2, respectively) augment the desensitization of the signaling characterized by decreased production of cAMP, whereas GRK5 and GRK6 do not affect the signaling (21). The desensitization process seems to involve the phosphorylation of the receptor (22). The region of the H 2 receptor interacting with these GRKs is not known so far.…”

Section: Roles Of C-terminal Tails Of Histamine Receptorsmentioning

confidence: 99%

Recent Advances in Molecular Pharmacology of the Histamine Systems: Roles of C-terminal Tails of Histamine Receptors

et al. 2006

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Abstract. G-protein-coupled receptors (GPCR) represent a large and diverse superfamily of integral membrane proteins to which histamine receptors belong. Increasing numbers of proteins have been identified to interact with the C-termini of GPCRs. These interactions are implicated in targeting, trafficking, and fine-tuning of signaling of GPCRs. Although the C-terminus of the histamine H 2 receptor has been suggested to play in agonist-induced internalization of the receptor, roles of the C-termini of the other three histamine receptors are not known. To date, there is no protein identified to interact with the C-termini of histamine receptors.

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Histamine H2 Receptor Desensitization: Involvement of a Select Array of G Protein-Coupled Receptor Kinases

Cited by 45 publications

References 35 publications

Histamine H2 Receptor Trafficking: Role of Arrestin, Dynamin, and Clathrin in Histamine H2 Receptor Internalization

Histamine H2 Receptor Trafficking: Role of Arrestin, Dynamin, and Clathrin in Histamine H2 Receptor Internalization

Expression of a G Protein-coupled Receptor (GPCR) Leads to Attenuation of Signaling by Other GPCRs

Recent Advances in Molecular Pharmacology of the Histamine Systems: Roles of C-terminal Tails of Histamine Receptors

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