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Perry-Hauser NA, VanDyck MW, Lee KH, Shi L, Javitch JA. Disentangling autoproteolytic cleavage from tethered agonist-dependent activation of the adhesion receptor ADGRL3. J Biol Chem 2022; 298:102594. [PMID: 36244455 PMCID: PMC9674912 DOI: 10.1016/j.jbc.2022.102594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/07/2022] Open
Abstract
Adhesion G protein-coupled receptor latrophilin 3 (ADGRL3), a cell adhesion molecule highly expressed in the central nervous system, acts in synapse formation through trans interactions with its ligands. It is largely unknown if these interactions serve a purely adhesive function or can modulate G protein signaling. To assess how different structural elements of ADGRL3 (e.g., the adhesive domains, autoproteolytic cleavage site, or tethered agonist (TA)) impact receptor function, we require constructs that disrupt specific receptor features without impacting others. While we showed previously that mutating conserved Phe and Met residues in the TA of ADGRL3-C-terminal fragment (CTF), a CTF truncated to the G protein-coupled receptor proteolysis site, abolishes receptor-mediated G protein activation, we now find that autoproteolytic cleavage is disrupted in the full-length version of this construct. To identify a construct that disrupts TA-dependent activity without impacting proteolysis, we explored other mutations in the TA. We found that mutating the sixth and seventh residues of the TA, Leu and Met, to Ala impaired activity in a serum response element activity assay for both full-length and CTF constructs. We confirmed this activity loss results from impaired G protein coupling using an assay that acutely exposes the TA through controlled proteolysis. The ADGRL3 mutant expresses normally at the cell surface, and immunoblotting shows that it undergoes normal autoproteolysis. Thus, we found a construct that disrupts tethered agonism while retaining autoproteolytic cleavage, providing a tool to disentangle these functions in vivo. Our approach and specific findings are likely to be broadly applicable to other adhesion receptors.
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Affiliation(s)
- Nicole A Perry-Hauser
- Departments of Psychiatry and Molecular Pharmacology and Therapeutics, Columbia University Vagelos College of Physicians and Surgeons, New York, New York, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - Max W VanDyck
- Department of Biochemistry, Vassar College, Poughkeepsie, New York, USA
| | - Kuo Hao Lee
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland, USA
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland, USA
| | - Jonathan A Javitch
- Departments of Psychiatry and Molecular Pharmacology and Therapeutics, Columbia University Vagelos College of Physicians and Surgeons, New York, New York, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA.
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Pawnikar S, Magenheimer BS, Munoz EN, Maser RL, Miao Y. Mechanism of tethered agonist-mediated signaling by polycystin-1. Proc Natl Acad Sci U S A 2022; 119:e2113786119. [PMID: 35522707 DOI: 10.1073/pnas.2113786119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Mutations of polycystin-1 (PC1) are the major cause (85% of cases) of autosomal dominant polycystic kidney disease (ADPKD), which is the fourth leading cause of kidney failure. PC1 is thought to function as an atypical G protein-coupled receptor, yet the mechanism by which PC1 regulates G-protein signaling remains poorly understood. A significant portion of ADPKD mutations of PC1 encode a protein with defects in maturation or reduced function that may be amenable to functional rescue. In this work, we have combined complementary biochemical and cellular assay experiments and accelerated molecular simulations, which revealed an allosteric transduction pathway in activation of the PC1 C-terminal fragment. Our findings will facilitate future rational drug design efforts targeting the PC1 signaling function. Polycystin-1 (PC1) is an important unusual G protein-coupled receptor (GPCR) with 11 transmembrane domains, and its mutations account for 85% of cases of autosomal dominant polycystic kidney disease (ADPKD). PC1 shares multiple characteristics with Adhesion GPCRs. These include a GPCR proteolysis site that autocatalytically divides these proteins into extracellular, N-terminal, and membrane-embedded, C-terminal fragments (CTF), and a tethered agonist (TA) within the N-terminal stalk of the CTF that is suggested to activate signaling. However, the mechanism by which a TA can activate PC1 is not known. Here, we have combined functional cellular signaling experiments of PC1 CTF expression constructs encoding wild type, stalkless, and three different ADPKD stalk variants with all-atom Gaussian accelerated molecular dynamics (GaMD) simulations to investigate TA-mediated signaling activation. Correlations of residue motions and free-energy profiles calculated from the GaMD simulations correlated with the differential signaling abilities of wild type and stalk variants of PC1 CTF. They suggested an allosteric mechanism involving residue interactions connecting the stalk, Tetragonal Opening for Polycystins (TOP) domain, and putative pore loop in TA-mediated activation of PC1 CTF. Key interacting residues such as N3074–S3585 and R3848–E4078 predicted from the GaMD simulations were validated by mutagenesis experiments. Together, these complementary analyses have provided insights into a TA-mediated activation mechanism of PC1 CTF signaling, which will be important for future rational drug design targeting PC1.
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Schulze A, Kleinau G, Neumann S, Scheerer P, Schöneberg T, Brüser A. The intramolecular agonist is obligate for activation of glycoprotein hormone receptors. FASEB J 2020; 34:11243-11256. [PMID: 32648604 DOI: 10.1096/fj.202000100r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 01/15/2023]
Abstract
In contrast to most rhodopsin-like G protein-coupled receptors, the glycoprotein hormone receptors (GPHR) have a large extracellular N-terminus for hormone binding. The hormones do not directly activate the transmembrane domain but mediate their action via a, thus, far only partially known Tethered Agonistic LIgand (TALI). The existence of such an intramolecular agonist was initially indicated by site-directed mutation studies and activating peptides derived from the extracellular hinge region. It is still unknown precisely how TALI is involved in intramolecular signal transmission. We combined systematic mutagenesis studies at the luteinizing hormone receptor and the thyroid-stimulating hormone receptor (TSHR), stimulation with a drug-like agonist (E2) of the TSHR, and structural homology modeling to unravel the functional and structural properties defining the TALI region. Here, we report that TALI (a) is predisposed to constitutively activate GPHR, (b) can by itself rearrange GPHR into a fully active conformation, (c) stabilizes active GPHR conformation, and (d) is not involved in activation of the TSHR by E2. In the active state conformation, TALI forms specific interactions between the N-terminus and the transmembrane domain. We show that stabilization of an active state is dependent on TALI, including activation by hormones and constitutively activating mutations.
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Affiliation(s)
- Annelie Schulze
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Gunnar Kleinau
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Susanne Neumann
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Antje Brüser
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany
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Zhu B, Luo R, Jin P, Li T, Oak HC, Giera S, Monk KR, Lak P, Shoichet BK, Piao X. GAIN domain-mediated cleavage is required for activation of G protein-coupled receptor 56 (GPR56) by its natural ligands and a small-molecule agonist. J Biol Chem 2019; 294:19246-19254. [PMID: 31628191 DOI: 10.1074/jbc.ra119.008234] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 10/02/2019] [Indexed: 12/15/2022] Open
Abstract
Adhesion G protein-coupled receptors (aGPCRs) represent a distinct family of GPCRs that regulate several developmental and physiological processes. Most aGPCRs undergo GPCR autoproteolysis-inducing domain-mediated protein cleavage, which produces a cryptic tethered agonist (termed Stachel (stinger)), and cleavage-dependent and -independent aGPCR signaling mechanisms have been described. aGPCR G1 (ADGRG1 or G protein-coupled receptor 56 (GPR56)) has pleiotropic functions in the development of multiple organ systems, which has broad implications for human diseases. To date, two natural GPR56 ligands, collagen III and tissue transglutaminase (TG2), and one small-molecule agonist, 3-α-acetoxydihydrodeoxygedunin (3-α-DOG), have been identified, in addition to a synthetic peptide, P19, that contains seven amino acids of the native Stachel sequence. However, the mechanisms by which these natural and small-molecule agonists signal through GPR56 remain unknown. Here we engineered a noncleavable receptor variant that retains signaling competence via the P19 peptide. We demonstrate that both natural and small-molecule agonists can activate only cleaved GPR56. Interestingly, TG2 required both receptor cleavage and the presence of a matrix protein, laminin, to activate GPR56, whereas collagen III and 3-α-DOG signaled without any cofactors. On the other hand, both TG2/laminin and collagen III activate the receptor by dissociating the N-terminal fragment from its C-terminal fragment, enabling activation by the Stachel sequence, whereas P19 and 3-α-DOG initiate downstream signaling without disengaging the N-terminal fragment from its C-terminal fragment. These findings deepen our understanding of how GPR56 signals via natural ligands, and a small-molecule agonist may be broadly applicable to other aGPCR family members.
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Affiliation(s)
- Beika Zhu
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Weill Institute of Neuroscience, University of California, San Francisco, California 94143
| | - Rong Luo
- Department of Medicine, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Peng Jin
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Weill Institute of Neuroscience, University of California, San Francisco, California 94143
| | - Tao Li
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Weill Institute of Neuroscience, University of California, San Francisco, California 94143
| | - Hayeon C Oak
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Weill Institute of Neuroscience, University of California, San Francisco, California 94143
| | - Stefanie Giera
- Department of Medicine, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Kelly R Monk
- Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239
| | - Parnian Lak
- Department of Pharmaceutical Chemistry and Quantitative Biology Institute, University of California, San Francisco, California 94143
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry and Quantitative Biology Institute, University of California, San Francisco, California 94143
| | - Xianhua Piao
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Weill Institute of Neuroscience, University of California, San Francisco, California 94143 .,Department of Medicine, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115.,Division of Neonatology, Department of Pediatrics, University of California, San Francisco, California 94158.,Newborn Brain Research Institute, University of California, San Francisco, California 94158
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Schöneberg T, Liebscher I, Luo R, Monk KR, Piao X. Tethered agonists: a new mechanism underlying adhesion G protein-coupled receptor activation. J Recept Signal Transduct Res 2015; 35:220-3. [PMID: 26366621 DOI: 10.3109/10799893.2015.1072978] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The family of adhesion G protein-coupled receptors (aGPCRs) comprises 33 members in the human genome, which are subdivided into nine subclasses. Many aGPCRs undergo an autoproteolytic process via their GPCR Autoproteolysis-INducing (GAIN) domain during protein maturation to generate an N- and a C-terminal fragments, NTF and CTF, respectively. The NTF and CTF are non-covalently reassociated on the plasma membrane to form a single receptor unit. How aGPCRs are activated upon ligand binding remains one of the leading questions in the field of aGPCR research. Recent work from our labs and others shows that ligand binding can remove the NTF from the plasma membrane-bound CTF, exposing a tethered agonist which potently activates downstream signaling.
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Affiliation(s)
- Torsten Schöneberg
- a Institute of Biochemistry, Medical Faculty, University of Leipzig , Leipzig , Germany
| | - Ines Liebscher
- a Institute of Biochemistry, Medical Faculty, University of Leipzig , Leipzig , Germany
| | - Rong Luo
- b Division of Newborn Medicine, Department of Medicine , Children's Hospital and Harvard Medical School , Boston , MA , USA
| | - Kelly R Monk
- c Department of Developmental Biology , Washington University School of Medicine , St. Louis , MO , USA , and.,d Hope Center for Neurological Disorders, Washington University School of Medicine , St. Louis , MO , USA
| | - Xianhua Piao
- b Division of Newborn Medicine, Department of Medicine , Children's Hospital and Harvard Medical School , Boston , MA , USA
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Stoveken HM, Hajduczok AG, Xu L, Tall GG. Adhesion G protein-coupled receptors are activated by exposure of a cryptic tethered agonist. Proc Natl Acad Sci U S A 2015; 112:6194-9. [PMID: 25918380 DOI: 10.1073/pnas.1421785112] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The large class of adhesion G protein-coupled receptors (aGPCRs) bind extracellular matrix or neighboring cell-surface ligands to regulate organ and tissue development through an unknown activation mechanism. We examined aGPCR activation using two prototypical aGPCRs, GPR56 and GPR110. Active dissociation of the noncovalently bound GPR56 or GPR110 extracellular domains (ECDs) from the respective seven-transmembrane (7TM) domains relieved an inhibitory influence and permitted both receptors to activate defined G protein subtypes. After ECD displacement, the newly revealed short N-terminal stalk regions of the 7TM domains were found to be essential for G protein activation. Synthetic peptides comprising these stalks potently activated GPR56 or GPR110 in vitro or in cells, demonstrating that the stalks comprise a tethered agonist that was encrypted within the ECD. Establishment of an aGPCR activation mechanism provides a rational platform for the development of aGPCR synthetic modulators that could find clinical utility toward aGPCR-directed disease.
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