Mechanism of dimerization of the human melanocortin 1 receptor

Zanna, Paola; Sánchez-Laorden, Berta; Pérez-Oliva, Ana B.; Turpin, María C.; Herráiz, Cecilia; Jiménez‐Cervantes, Celia; García‐Borrón, José C.

doi:10.1016/j.bbrc.2008.01.060

Cited by 32 publications

(33 citation statements)

References 25 publications

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“…Only a few mechanisms by which heptahelical transmembrane receptors are able to form dimers are known. One possibility is the formation of covalent disulfide bonds between receptor monomers (Berthouze et al, 2007;Zanna et al, 2008). However, the contribution of disulfide bonds to AdipoR1 dimerization is rather unlikely, because we also observed the dimers under reducing conditions in the presence of -mercaptoethanol (Fig.…”

Section: Discussionmentioning

confidence: 81%

Dimerization of adiponectin receptor 1 is inhibited by adiponectin

Kosel

Heiker

Juhl

et al. 2010

Journal of Cell Science

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SummaryAdipoR1 and AdipoR2 are newly discovered members of the huge family of seven-transmembrane receptors, but both receptors are structurally and functionally different from G-protein-coupled receptors. Little is known about the oligomerization of the AdipoRs. Here, we show the presence of endogenous AdipoR1 dimers in various cell lines and human muscle tissue. To directly follow and localize the dimerization, we applied bimolecular fluorescence complementation (BiFC) in combination with flow cytometry. We visualized and quantified AdipoR1 homodimers in HEK293 cells. Moreover, we identified a GxxxG dimerization motif in the fifth transmembrane domain of the AdipoR1. By mutating both glycine residues to phenylalanine or glutamic acid, we were able to modulate the dimerization of AdipoR1, implicating a role for the GxxxG motif in AdipoR1 dimerization. Furthermore, we tested whether the AdipoR1 ligand adiponectin had any influence on receptor dimerization. Interestingly, we found that adiponectin decreases the receptor dimerization in a concentration-dependent manner. This effect is mainly mediated by segments of the collagen-like domain of fulllength adiponectin. Accordingly, this is the first direct read-out signal of adiponectin at the AdipoR1 receptor, which revealed the involvement of specific amino acids of both the receptor and the ligand to modulate the quaternary structure of the AdipoR1.

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Section: Discussionmentioning

confidence: 81%

Dimerization of adiponectin receptor 1 is inhibited by adiponectin

Kosel

Heiker

Juhl

et al. 2010

Journal of Cell Science

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“…The MC2 receptor appears to dimerize equally well with or without MRAP. There is no direct evidence that melanocortin receptors must dimerize to traffic to the cell surface, but homo-and heterodimerization of class A GPCRs is well documented and MC1 and MC3 receptors have been shown to form homo-and heterodimers (17)(18)(19). In general, dimerization of GPCRs occurs in the ER at early stages in receptor biosynthesis, and dimerization explains dominant negative effects of some naturally occurring receptor mutations (22,23), including several in the melanocortin receptor family (24).…”

Section: Discussionmentioning

confidence: 99%

“…Effect of MRAP on Receptor Dimerization-Several of the melanocortin receptors have been reported to form homodimers and heterodimers (17)(18)(19). To determine if MC2 or MC5 receptors form homodimers or oligomers and if such complexes are affected by MRAP, we co-expressed MC2 receptor carboxyl-terminally fused to YFP-F1 with MC2 receptor fused to YFP-F2 in the presence or absence of MRAP.…”

Section: Effect Of Mrap On Mc5mentioning

confidence: 99%

Opposite Effects of the Melanocortin-2 (MC2) Receptor Accessory Protein MRAP on MC2 and MC5 Receptor Dimerization and Trafficking

Sebag

Hinkle

2009

Journal of Biological Chemistry

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MC2 (ACTH) receptors require MC2 receptor accessory protein (MRAP) to reach the cell surface. In this study, we show that MRAP has the opposite effect on the closely related MC5 receptor. In enzyme-linked immunosorbent assay and microscopy experiments, MC2 receptor was retained in the endoplasmic reticulum in the absence of MRAP and targeted to the plasma membrane with MRAP. MC5 receptor was at the plasma membrane in the absence of MRAP, but trapped intracellularly when expressed with MRAP. Using bimolecular fluorescence complementation, where one fragment of yellow fluorescent protein (YFP) was fused to receptors and another to MRAP, we showed that MC2 receptor-MRAP dimers were present at the plasma membrane, whereas MC5 receptor-MRAP dimers were intracellular. Both MC2 and MC5 receptors co-precipitated with MRAP. MRAP did not alter expression of ␤2-adrenergic receptors or co-precipitate with them. To determine if MRAP affects formation of receptor oligomers, we co-expressed MC2 receptors fused to YFP fragments in the presence or absence of MRAP. YFP fluorescence, reporting MC2 receptor homodimers, was readily detectable with or without MRAP. In contrast, MC5 receptor homodimers were visible in the absence of MRAP, but little fluorescence was observed by microscopic analysis when MRAP was co-expressed. Co-precipitation of differentially tagged receptors confirmed that MRAP blocks MC5 receptor dimerization. The regions of MRAP required for its effects on MC2 and MC5 receptors differed. These results establish that MRAP forms stable complexes with two different melanocortin receptors, facilitating surface expression of MC2 receptor but disrupting dimerization and surface localization of MC5 receptor.In mammals, the five members of the melanocortin (MC 2 ) receptor family play diverse physiological roles. MC1 receptors (melanocyte-stimulating hormone receptors) control pigmentation in many animals, MC2 receptors (ACTH receptors) regulate adrenal corticosteroid synthesis, MC3 and MC4 receptors in brain influence food intake and energy expenditure, and MC5 receptors control exocrine gland secretion (1). Melanocortin receptors (MC1 through MC5) are structurally related G protein-coupled receptors that respond to agonists with an increase in cAMP. The receptors differ in their affinity for physiological agonists (␣-, ␤-, and ␥-melanocyte-stimulating hormone and ACTH) and antagonists (agouti and agouti-related protein).Unlike other melanocortin receptors, MC2 receptors are selectively regulated by ACTH. The MC2 receptor is also unusual in its requirement for an accessory protein, the MC2 receptor accessory protein (MRAP) (2). MRAP must be expressed with the MC2 receptor in order for the receptor to undergo glycosylation, traffic to the plasma membrane, bind ACTH, and stimulate adenylyl cyclase (2-4). Individuals with inactivating mutations of either the MC2 receptor or MRAP suffer from ACTH resistance and severe glucocorticoid deficiency (2).MRAP is a small protein with a conserved amino terminus, single membrane-spann...

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“…A significant number of these receptors are shown to form homo-or heterocomplexes, suggesting that oligomerization of GPCRs may be a quite general phenomenon. For instance, MC1R (Zanna et al, 2008;Mandrika et al, 2005;Sánchez-Laorden et al, 2006) and MC4R (Nickolls and Maki, 2006) have the ability to homodimerize and MC1R and MC3R form heterodimers when expressed in Cos-7 cells (Mandrika et al, 2005). Our results demonstrate that, in HEK293 cells, MC5R-GFP is correctly addressed to the cellsurface and is functionally active in the absence of other melanocortin receptors.…”

Section: Discussionmentioning

confidence: 99%

Melanocortin 5 receptor activates ERK1/2 through a PI3K-regulated signaling mechanism

Rodrigues

Pignatelli

Almeida

et al. 2009

Molecular and Cellular Endocrinology

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receptor activates ERK1/2 through a PI3K-regulated signaling mechanism. Molecular and Cellular Endocrinology, Elsevier, 2009, 303 (1-2) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t SummaryMelanocortin 5 receptor (MC5R) is a G-protein coupled receptor (GPCR) with high affinity for α-MSH. To unravel some of the downstream cell-signaling pathways activated by this receptor, HEK293 cells were transiently and stably transfected with a vector encoding green fluorescent protein (GFP)-tagged MC5R. In these cells the receptor was correctly addressed to the cell surface and was functional, as shown by the MC5R-induced formation of intracellular cAMP. In fact, the MC5R agonist α-MSH induced a 10 or 16 fold increase (transient or stable cells, respectively) above the cAMP levels found in unstimulated cells. Moreover, in cells stably expressing MC5R-GFP, α-MSH promoted ERK1/2 phosphorylation in a dose-dependent manner (EC50=7.3nM) with the maximal effect occurring after 5min of agonist incubation. The signaling pathway conveyed through ERK1/2 is not linked to cAMP, since the phosphorylation of these kinases is unchanged by the inhibition of adenylyl cyclase. Also, ERK1/2 activation is not significantly affected by PKA, PKC and Akt/PKB specific inhibitors. However, α-MSH-induced ERK1/2 activation is abolished by the PI3K inhibitors wortmannin and LY294002. Altogether, these findings demonstrate that MC5R signals through a PI3K-regulated Akt-independent pathway leading to downstream activation of ERK1/2. The involvement of these MAPK suggests that MC5R could be implicated in cellular proliferation or differentiation mechanisms.

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Mechanism of dimerization of the human melanocortin 1 receptor

Cited by 32 publications

References 25 publications

Dimerization of adiponectin receptor 1 is inhibited by adiponectin

Dimerization of adiponectin receptor 1 is inhibited by adiponectin

Opposite Effects of the Melanocortin-2 (MC2) Receptor Accessory Protein MRAP on MC2 and MC5 Receptor Dimerization and Trafficking

Melanocortin 5 receptor activates ERK1/2 through a PI3K-regulated signaling mechanism

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