Abstract
Prostaglandin D 2 activation of the seven-transmembrane receptor CRTH2 regulates numerous cell functions that are important in inflammatory diseases, such as asthma. Despite its disease implication, no studies to date aimed at identifying receptor domains governing signaling and surface expression of human CRTH2. We tested the hypothesis that CRTH2 may take advantage of its C-tail to silence its own signaling and that this mechanism may explain the poor functional responses observed with CRTH2 in heterologous expression systems. Although the C terminus is a critical determinant for retention of CRTH2 at the plasma membrane, the presence of this domain confers a signaling-compromised conformation onto the receptor. Indeed, a mutant receptor lacking the major portion ofits C-terminal tail displays paradoxically enhanced Gα i and ERK1/2 activation despite enhanced constitutive and agonist-mediated internalization. Enhanced activation of Gα i proteins and downstream signaling cascades is probably due to the inability of the tail-truncated receptor to recruit β-arrestin2 and undergo homologous desensitization. Unexpectedly, CRTH2 is not phosphorylated upon agonist-stimulation, a primary mechanism by which GPCR activity is regulated. Dynamic mass redistribution assays, which allow label-free monitoring of all major G protein pathways in real time, confirm that the C terminus inhibits Gα i signaling of CRTH2 but does not encode G protein specificity determinants. We propose that intrinsic CRTH2 inhibition by its C terminus may represent a rather unappreciated strategy employed by a GPCR to specify the extent of G protein activation and that this mechanism may compensate for the absence of the classical phosphorylation-dependent signal attenuation.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1324-1336 |
| Number of pages | 13 |
| Journal | Journal of Biological Chemistry |
| Volume | 284 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 9 2009 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology
Cite this
The C-terminal tail of CRTH2 is a key molecular determinant that constrains Gα i and downstream signaling cascade activation. / Schröder, Ralf; Merten, Nicole; Mathiesen, Jesper Mosolff; Martini, Lene; Kruljac-Letunic, Anamarija; Krop, Friederike; Blaukat, Andree; Fang, Ye; Tran, Elizabeth; Ulven, Trond; Drewke, Christel; Whistler, Jennifer; Pardo, Leonardo; Gomeza, Jesús; Kostenis, Evi.
In: Journal of Biological Chemistry, Vol. 284, No. 2, 09.01.2009, p. 1324-1336.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The C-terminal tail of CRTH2 is a key molecular determinant that constrains Gα i and downstream signaling cascade activation
AU - Schröder, Ralf
AU - Merten, Nicole
AU - Mathiesen, Jesper Mosolff
AU - Martini, Lene
AU - Kruljac-Letunic, Anamarija
AU - Krop, Friederike
AU - Blaukat, Andree
AU - Fang, Ye
AU - Tran, Elizabeth
AU - Ulven, Trond
AU - Drewke, Christel
AU - Whistler, Jennifer
AU - Pardo, Leonardo
AU - Gomeza, Jesús
AU - Kostenis, Evi
PY - 2009/1/9
Y1 - 2009/1/9
N2 - Prostaglandin D 2 activation of the seven-transmembrane receptor CRTH2 regulates numerous cell functions that are important in inflammatory diseases, such as asthma. Despite its disease implication, no studies to date aimed at identifying receptor domains governing signaling and surface expression of human CRTH2. We tested the hypothesis that CRTH2 may take advantage of its C-tail to silence its own signaling and that this mechanism may explain the poor functional responses observed with CRTH2 in heterologous expression systems. Although the C terminus is a critical determinant for retention of CRTH2 at the plasma membrane, the presence of this domain confers a signaling-compromised conformation onto the receptor. Indeed, a mutant receptor lacking the major portion ofits C-terminal tail displays paradoxically enhanced Gα i and ERK1/2 activation despite enhanced constitutive and agonist-mediated internalization. Enhanced activation of Gα i proteins and downstream signaling cascades is probably due to the inability of the tail-truncated receptor to recruit β-arrestin2 and undergo homologous desensitization. Unexpectedly, CRTH2 is not phosphorylated upon agonist-stimulation, a primary mechanism by which GPCR activity is regulated. Dynamic mass redistribution assays, which allow label-free monitoring of all major G protein pathways in real time, confirm that the C terminus inhibits Gα i signaling of CRTH2 but does not encode G protein specificity determinants. We propose that intrinsic CRTH2 inhibition by its C terminus may represent a rather unappreciated strategy employed by a GPCR to specify the extent of G protein activation and that this mechanism may compensate for the absence of the classical phosphorylation-dependent signal attenuation.
AB - Prostaglandin D 2 activation of the seven-transmembrane receptor CRTH2 regulates numerous cell functions that are important in inflammatory diseases, such as asthma. Despite its disease implication, no studies to date aimed at identifying receptor domains governing signaling and surface expression of human CRTH2. We tested the hypothesis that CRTH2 may take advantage of its C-tail to silence its own signaling and that this mechanism may explain the poor functional responses observed with CRTH2 in heterologous expression systems. Although the C terminus is a critical determinant for retention of CRTH2 at the plasma membrane, the presence of this domain confers a signaling-compromised conformation onto the receptor. Indeed, a mutant receptor lacking the major portion ofits C-terminal tail displays paradoxically enhanced Gα i and ERK1/2 activation despite enhanced constitutive and agonist-mediated internalization. Enhanced activation of Gα i proteins and downstream signaling cascades is probably due to the inability of the tail-truncated receptor to recruit β-arrestin2 and undergo homologous desensitization. Unexpectedly, CRTH2 is not phosphorylated upon agonist-stimulation, a primary mechanism by which GPCR activity is regulated. Dynamic mass redistribution assays, which allow label-free monitoring of all major G protein pathways in real time, confirm that the C terminus inhibits Gα i signaling of CRTH2 but does not encode G protein specificity determinants. We propose that intrinsic CRTH2 inhibition by its C terminus may represent a rather unappreciated strategy employed by a GPCR to specify the extent of G protein activation and that this mechanism may compensate for the absence of the classical phosphorylation-dependent signal attenuation.
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U2 - 10.1074/jbc.M806867200
DO - 10.1074/jbc.M806867200
M3 - Article
C2 - 19010788
AN - SCOPUS:59449089513
VL - 284
SP - 1324
EP - 1336
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 2
ER -