Structure and function of Cross-class complexes of G Protein-Coupled secretin and angiotensin 1a receptors

Kaleeckal G. Harikumar, Mary Lou Augustine, Leo T O Lee, Billy K C Chow, Laurence J Miller

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Complexes of secretin (SecR) and angiotensin 1a (Atr1a) receptors have been proposed to be functionally important in osmoregulation, providing an explanation for overlapping and interdependent functions of hormones that bind and activate different classes of GPCRs. However, the nature of these crossclass complexes has not been well characterized and their signaling properties have not been systematically explored. We now use competitive inhibition of receptor bioluminescence resonance energy transfer and bimolecular fluorescence complementation to establish the dominant functionally important state as a symmetrical homodimeric form of SecR decorated by monomeric Atr1a, interacting through lipid-exposed faces of Atr1a TM1 and TM4. Conditions increasing prevalence of this complex exhibited negative allosteric modulatory impact on secretin-stimulated cAMP responses at SecR. In contrast, activating Atr1a with full agonist in such a complex exhibited a positive allosteric modulatory impact on the same signaling event. This modulation was functionally biased, with secretin-stimulated calcium responses unaffected, whereas angiotensin-stimulated calcium responses through the complex were reduced or absent. Further supporting this interpretation, Atr1a with mutations of lipid-exposed faces of TM1 and TM4 that did not affect its ability to bind or signal, could be expressed in the same cell as SecR, yet not exhibit either the negative or positive allosteric impact on cAMP observed with the inactive or activated states of wild type Atr1a on function, and not interfere with angiotensin-stimulated calcium responses like complexes with Atr1a. This may provide a more selective means of exploring the physiologic functional impact of this cross-class receptor complex without interfering with the function of either component receptor.

Original languageEnglish (US)
Pages (from-to)17332-17344
Number of pages13
JournalJournal of Biological Chemistry
Volume291
Issue number33
DOIs
StatePublished - Aug 12 2016

Fingerprint

Angiotensin Receptors
Secretin
Angiotensins
GTP-Binding Proteins
Calcium
Bioluminescence
Lipids
Osmoregulation
Fluorescence Resonance Energy Transfer
Energy transfer
Fluorescence
Modulation
Hormones
Mutation

ASJC Scopus subject areas

  • Biochemistry
  • Medicine(all)
  • Molecular Biology
  • Cell Biology

Cite this

Structure and function of Cross-class complexes of G Protein-Coupled secretin and angiotensin 1a receptors. / Harikumar, Kaleeckal G.; Augustine, Mary Lou; Lee, Leo T O; Chow, Billy K C; Miller, Laurence J.

In: Journal of Biological Chemistry, Vol. 291, No. 33, 12.08.2016, p. 17332-17344.

Research output: Contribution to journalArticle

Harikumar, Kaleeckal G. ; Augustine, Mary Lou ; Lee, Leo T O ; Chow, Billy K C ; Miller, Laurence J. / Structure and function of Cross-class complexes of G Protein-Coupled secretin and angiotensin 1a receptors. In: Journal of Biological Chemistry. 2016 ; Vol. 291, No. 33. pp. 17332-17344.
@article{be9622f029e84ed38a8c6e45fc55c792,
title = "Structure and function of Cross-class complexes of G Protein-Coupled secretin and angiotensin 1a receptors",
abstract = "Complexes of secretin (SecR) and angiotensin 1a (Atr1a) receptors have been proposed to be functionally important in osmoregulation, providing an explanation for overlapping and interdependent functions of hormones that bind and activate different classes of GPCRs. However, the nature of these crossclass complexes has not been well characterized and their signaling properties have not been systematically explored. We now use competitive inhibition of receptor bioluminescence resonance energy transfer and bimolecular fluorescence complementation to establish the dominant functionally important state as a symmetrical homodimeric form of SecR decorated by monomeric Atr1a, interacting through lipid-exposed faces of Atr1a TM1 and TM4. Conditions increasing prevalence of this complex exhibited negative allosteric modulatory impact on secretin-stimulated cAMP responses at SecR. In contrast, activating Atr1a with full agonist in such a complex exhibited a positive allosteric modulatory impact on the same signaling event. This modulation was functionally biased, with secretin-stimulated calcium responses unaffected, whereas angiotensin-stimulated calcium responses through the complex were reduced or absent. Further supporting this interpretation, Atr1a with mutations of lipid-exposed faces of TM1 and TM4 that did not affect its ability to bind or signal, could be expressed in the same cell as SecR, yet not exhibit either the negative or positive allosteric impact on cAMP observed with the inactive or activated states of wild type Atr1a on function, and not interfere with angiotensin-stimulated calcium responses like complexes with Atr1a. This may provide a more selective means of exploring the physiologic functional impact of this cross-class receptor complex without interfering with the function of either component receptor.",
author = "Harikumar, {Kaleeckal G.} and Augustine, {Mary Lou} and Lee, {Leo T O} and Chow, {Billy K C} and Miller, {Laurence J}",
year = "2016",
month = "8",
day = "12",
doi = "10.1074/jbc.M116.730754",
language = "English (US)",
volume = "291",
pages = "17332--17344",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "33",

}

TY - JOUR

T1 - Structure and function of Cross-class complexes of G Protein-Coupled secretin and angiotensin 1a receptors

AU - Harikumar, Kaleeckal G.

AU - Augustine, Mary Lou

AU - Lee, Leo T O

AU - Chow, Billy K C

AU - Miller, Laurence J

PY - 2016/8/12

Y1 - 2016/8/12

N2 - Complexes of secretin (SecR) and angiotensin 1a (Atr1a) receptors have been proposed to be functionally important in osmoregulation, providing an explanation for overlapping and interdependent functions of hormones that bind and activate different classes of GPCRs. However, the nature of these crossclass complexes has not been well characterized and their signaling properties have not been systematically explored. We now use competitive inhibition of receptor bioluminescence resonance energy transfer and bimolecular fluorescence complementation to establish the dominant functionally important state as a symmetrical homodimeric form of SecR decorated by monomeric Atr1a, interacting through lipid-exposed faces of Atr1a TM1 and TM4. Conditions increasing prevalence of this complex exhibited negative allosteric modulatory impact on secretin-stimulated cAMP responses at SecR. In contrast, activating Atr1a with full agonist in such a complex exhibited a positive allosteric modulatory impact on the same signaling event. This modulation was functionally biased, with secretin-stimulated calcium responses unaffected, whereas angiotensin-stimulated calcium responses through the complex were reduced or absent. Further supporting this interpretation, Atr1a with mutations of lipid-exposed faces of TM1 and TM4 that did not affect its ability to bind or signal, could be expressed in the same cell as SecR, yet not exhibit either the negative or positive allosteric impact on cAMP observed with the inactive or activated states of wild type Atr1a on function, and not interfere with angiotensin-stimulated calcium responses like complexes with Atr1a. This may provide a more selective means of exploring the physiologic functional impact of this cross-class receptor complex without interfering with the function of either component receptor.

AB - Complexes of secretin (SecR) and angiotensin 1a (Atr1a) receptors have been proposed to be functionally important in osmoregulation, providing an explanation for overlapping and interdependent functions of hormones that bind and activate different classes of GPCRs. However, the nature of these crossclass complexes has not been well characterized and their signaling properties have not been systematically explored. We now use competitive inhibition of receptor bioluminescence resonance energy transfer and bimolecular fluorescence complementation to establish the dominant functionally important state as a symmetrical homodimeric form of SecR decorated by monomeric Atr1a, interacting through lipid-exposed faces of Atr1a TM1 and TM4. Conditions increasing prevalence of this complex exhibited negative allosteric modulatory impact on secretin-stimulated cAMP responses at SecR. In contrast, activating Atr1a with full agonist in such a complex exhibited a positive allosteric modulatory impact on the same signaling event. This modulation was functionally biased, with secretin-stimulated calcium responses unaffected, whereas angiotensin-stimulated calcium responses through the complex were reduced or absent. Further supporting this interpretation, Atr1a with mutations of lipid-exposed faces of TM1 and TM4 that did not affect its ability to bind or signal, could be expressed in the same cell as SecR, yet not exhibit either the negative or positive allosteric impact on cAMP observed with the inactive or activated states of wild type Atr1a on function, and not interfere with angiotensin-stimulated calcium responses like complexes with Atr1a. This may provide a more selective means of exploring the physiologic functional impact of this cross-class receptor complex without interfering with the function of either component receptor.

UR - http://www.scopus.com/inward/record.url?scp=84981356892&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84981356892&partnerID=8YFLogxK

U2 - 10.1074/jbc.M116.730754

DO - 10.1074/jbc.M116.730754

M3 - Article

C2 - 27330080

AN - SCOPUS:84981356892

VL - 291

SP - 17332

EP - 17344

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 33

ER -