Abstract
Angiotensin (ANGII) and secretin (SCT) share overlapping, interdependent osmoregulatory functions in brain, where SCT peptide/receptor function is required for ANGII action, yet the molecular basis is unknown. Since receptors for these peptides (AT1aR, SCTR) are coexpressed in osmoregulatory centers, a possible mechanism is formation of a crossclass receptor heterocomplex. Here, we demonstrate such a complex and its functional importance to modulate signaling. Association of AT1aR with SCTR reduced ability of SCT to stimulate cyclic adenosine monophosphate (cAMP), with signaling augmented in presence of ANGII or constitutively active AT1aR. Several transmembrane (TM) peptides of these receptors were able to affect their conformation within complexes, reducing receptor BRET signals. AT1aR TM1 affected only formation and activity of the heterocomplex, without effect on homomers of either receptor, and reduced SCT-stimulated cAMP responses in cells expressing both receptors. This peptide was active in vivo by injection into mouse lateral ventricle, thereby suppressing water-drinking behavior after hyperosmotic shock, similar to SCTR knockouts. This supports the interpretation that active conformation of AT1aR is a key modulator of cAMP responses induced by SCT stimulation of SCTR. The SCTR/AT1aR complex is physiologically important, providing differential signaling to SCT in settings of hyperosmolality or food intake, modulated by differences in levels of ANGII.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2632-2644 |
| Number of pages | 13 |
| Journal | FASEB Journal |
| Volume | 28 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2014 |
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Keywords
- Angiotensin II
- In vivo analysis
- Secretin
ASJC Scopus subject areas
- Biochemistry
- Biotechnology
- Genetics
- Molecular Biology
Cite this
Transmembrane peptides as unique tools to demonstrate the in vivo action of a cross-class GPCR heterocomplex. / Lee, Leo T O; Ng, Stephanie Y L; Chu, Jessica Y S; Sekar, Revathi; Harikumar, Kaleeckal G.; Miller, Laurence J; Chow, Billy K C.
In: FASEB Journal, Vol. 28, No. 6, 2014, p. 2632-2644.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Transmembrane peptides as unique tools to demonstrate the in vivo action of a cross-class GPCR heterocomplex
AU - Lee, Leo T O
AU - Ng, Stephanie Y L
AU - Chu, Jessica Y S
AU - Sekar, Revathi
AU - Harikumar, Kaleeckal G.
AU - Miller, Laurence J
AU - Chow, Billy K C
PY - 2014
Y1 - 2014
N2 - Angiotensin (ANGII) and secretin (SCT) share overlapping, interdependent osmoregulatory functions in brain, where SCT peptide/receptor function is required for ANGII action, yet the molecular basis is unknown. Since receptors for these peptides (AT1aR, SCTR) are coexpressed in osmoregulatory centers, a possible mechanism is formation of a crossclass receptor heterocomplex. Here, we demonstrate such a complex and its functional importance to modulate signaling. Association of AT1aR with SCTR reduced ability of SCT to stimulate cyclic adenosine monophosphate (cAMP), with signaling augmented in presence of ANGII or constitutively active AT1aR. Several transmembrane (TM) peptides of these receptors were able to affect their conformation within complexes, reducing receptor BRET signals. AT1aR TM1 affected only formation and activity of the heterocomplex, without effect on homomers of either receptor, and reduced SCT-stimulated cAMP responses in cells expressing both receptors. This peptide was active in vivo by injection into mouse lateral ventricle, thereby suppressing water-drinking behavior after hyperosmotic shock, similar to SCTR knockouts. This supports the interpretation that active conformation of AT1aR is a key modulator of cAMP responses induced by SCT stimulation of SCTR. The SCTR/AT1aR complex is physiologically important, providing differential signaling to SCT in settings of hyperosmolality or food intake, modulated by differences in levels of ANGII.
AB - Angiotensin (ANGII) and secretin (SCT) share overlapping, interdependent osmoregulatory functions in brain, where SCT peptide/receptor function is required for ANGII action, yet the molecular basis is unknown. Since receptors for these peptides (AT1aR, SCTR) are coexpressed in osmoregulatory centers, a possible mechanism is formation of a crossclass receptor heterocomplex. Here, we demonstrate such a complex and its functional importance to modulate signaling. Association of AT1aR with SCTR reduced ability of SCT to stimulate cyclic adenosine monophosphate (cAMP), with signaling augmented in presence of ANGII or constitutively active AT1aR. Several transmembrane (TM) peptides of these receptors were able to affect their conformation within complexes, reducing receptor BRET signals. AT1aR TM1 affected only formation and activity of the heterocomplex, without effect on homomers of either receptor, and reduced SCT-stimulated cAMP responses in cells expressing both receptors. This peptide was active in vivo by injection into mouse lateral ventricle, thereby suppressing water-drinking behavior after hyperosmotic shock, similar to SCTR knockouts. This supports the interpretation that active conformation of AT1aR is a key modulator of cAMP responses induced by SCT stimulation of SCTR. The SCTR/AT1aR complex is physiologically important, providing differential signaling to SCT in settings of hyperosmolality or food intake, modulated by differences in levels of ANGII.
KW - Angiotensin II
KW - In vivo analysis
KW - Secretin
UR - http://www.scopus.com/inward/record.url?scp=84901853305&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901853305&partnerID=8YFLogxK
U2 - 10.1096/fj.13-246868
DO - 10.1096/fj.13-246868
M3 - Article
C2 - 24599969
AN - SCOPUS:84901853305
VL - 28
SP - 2632
EP - 2644
JO - FASEB Journal
JF - FASEB Journal
SN - 0892-6638
IS - 6
ER -