The direction of the longitudinal axis is fixed by defining nose residues on the arrestin (res. Molecular basis of beta-arrestin coupling to formoterol-bound beta1-adrenoceptor. Identify the highlighted tissue. C) renal column A . Regions missing in the templates both of PTH1R (e.g. Complete the sentence by adding a personal pronoun that agrees with the antecedent. Blood is recognized as a form of connective tissue sine it contains a non Closely attached to each other forming a protective barrier. $$ The highlighted cell type adipose connective tissue. In all cases, the phosphorylated receptor tail binds to the arrestin N-domain, whereas the 7-transmembrane (7TM) domain holds the arrestin central crest. The crude was treated with 150mL diethyl ether and filtered off to obtain 18.2g (4.00mmol) of BrEtY TFA salt (4) as a white solid in 90% yield. Distinct G protein-coupled receptor phosphorylation motifs modulate arrestin affinity and activation and global conformation. Anterior interventricular artery. D) left braciocephalic artery. Reported to North America / Corporate Audit Director. Sci. Select a word from the word web to complete this sentence -- Their home had a pleasant and gracious ______. Protein Sci. Zafin. Here, we characterize the PTH(1-34)-PTH1R-arr2 complex in the natural environment of living cells. Question: PAL: Models > Nervous System - Special Senses > Lab Practical > Question 24 Part A Identify the highlighted structure. Mol. The next day, cells were trypsinized and transferred to poly-d-lysine (PDL) coated 96-well plates with a density of 70,000 cells per well. Nat. Image 01 : Highlighted structure indicates Adrenal Zona glomerulosa . B) epiglottis A: Plant anatomy is used to study the internal structure of the plants. After 48h, the media was aspirated and the cells were stimulated for 90min with 1mL activation buffer supplemented with 200nM PTH(1-34). Which epithelium is responsible for protection, secretion, and absorption? pT503-K11, pT503-R25, pT503-K294, and pS504-K10). What is secreted by the highlighted cell? MD trajectories were analyzed using MdTraj package68. Identify the highlighted epithelial type. Identify the formed element labeled "c." The orientation of arr2 relative to PTH1R was measured in terms of pitch, roll, and yaw angles of rotation around their principal axes. As these features are conserved in several GPCRs, our work provides unique complementary information to existing structural data. J. Biol. Identify the highlighted structures. Zhang, Q. et al. C) lymphocyte M.T. What blood type can receive blood from anyone? The membranes were blocked with 5% non-fat dry milk (NFDM) in TBS-T (20mM Tris-HCl pH 7.4, 150mM NaCl and 0.1% (v/v) Tween-20) for at least 1h at RT. Identify the highlighted structure. volume14, Articlenumber:1151 (2023) C150 of arr2 was mutated to Ser to prevent intramolecular crosslinking with BrEtY placed in the N-domain39. mineralocorticoids. Identified Q&As 32. 8a, Supplementary Data1). B) platelet A) pancreas , \Delta H H, and \Delta S S for this process, and justify your choices. & Vilardaga, J.-P. International Union of Basic and Clinical Pharmacology. Downstream of helix VIII (N463F483), PTH1R features an ~100-residue long flexible C-terminal tail (C-term, K484M593), which was not resolved in these structures. C) ureter Only a few structures of GPCR-arrestin complexes have been solved so far: rhodopsin-arr1 fusion18,19,20, and arr2 in complex with neurotensin receptor type 1 (NTS1R)21,22, chimeric muscarinic acetylcholine receptor M2 (M2R)23, and beta-1adrenergic receptor (1-AR)24 fused to the highly phosphorylated tail of the vasopressin V2 receptor (V2R-phosphopeptide, V2Rpp). Biochemistry 33, 56615673 (1994). and to identify which . What term describes the various protein markers located in the plasma membrane of a red blood cell? D) pharynx, What part of the kidney is continuous with the ureter? rogers outage brampton today; levelland, tx obituaries. What structure receives blood from the venae cavae? Cells were transfected using PEI (Polysciences, Warrington, PA) at a PEI:DNA ratio of 3:1 (w/w) in lactate buffered saline (20mM sodium lactate pH 4 and 150mM NaCl)62. Abstract Skip Background: Section Background: The field of software testing is growing and rapidly-evolving. C) B+ Nat. (ed.) Proc. Arrestin mobilizes signaling proteins to the cytoskeleton and redirects their activity. Vishnivetskiy, S. A. et al. B. et al. 4a). Identify the highlighted structures. Identify the highlighted cell. Zhao, L.-H. et al. Identify the epithelium indicated by the arrows. 26, 11231131 (2019). What is the patient's blood type? To analyze the dynamic accessibility of the residue pairs for crosslinking, as well as the overall conformational stability of the complex, we performed unbiased Molecular Dynamics (MD) simulations without crosslinking restraints. Structural details of a Class B GPCR-arrestin complex revealed by genetically encoded crosslinkers in living cells. Substitutions of native Cys residues in arr2 were shown not to affect its receptor binding42. Two additional hits were detected in the central region of the C-domain (A344) and at the C-edge (N225). studying_101_just . Sci. No structural data are available for arrestin complexes with receptors belonging to GPCR subfamilies outside of class A (rhodopsin-like). __nucleus of fat cells or Nuclei of adipocytes in adipose tissue. The highlighted fibers are produced by what cell type? We validated this position of the proximal phosphorylation cluster at the external edge of the N-domain by assessing whether an alternative pose involving interactions with the finger loop, as it was observed in the structure of the arr2-V2Rpp complex (Supplementary Fig. 67, 310337 (2015). Exploring pairwise chemical crosslinking to study peptidereceptor interactions. HEK293T cells were seeded at 500,000 cells per well in 6-well plates in full DMEM. Is the highlighted epithelium considered to be stratified or simple? All sequences were verified by Sanger sequencing (Microsynth Seqlab Gttingen, DE). 5). The highlighted epithelium, when found lining a blood vessel, is called a(n). What is a text file and what is a binary file? (a) $V_1=0$. D) larynx, Which structure is highlighted? This large set of spatial constraints is used in extensive conformational sampling to generate optimized all-atom structural models of the PTH1R-arr2 complex, which are stable in unbiased MD simulations. C) celiac trunk Miedlich, S. U. Identify the highlighted structures, which anchor the atrioventricular valves. For each frame in a trajectory, we can then solve \({{{{{{\bf{X}}}}}}}_{{{{{{\rm{PTH}}}}}}1{{{{{\rm{R}}}}}}}={{{{{\bf{R}}}}}}{{{{{{\bf{X}}}}}}}_{{{{{{\rm{Arr}}}}}}}\)for the rotation matrix \({{{{{\bf{R}}}}}}\). Communication is a process in which a sender transmits signals to one or more receivers to control and coordinate . Distinct conformations of GPCRbeta-arrestin complexes mediate desensitization, signaling, and endocytosis. Seyedabadi, M., Gharghabi, M., Gurevich, E. V. & Gurevich, V. V. Receptor-arrestin interactions: the GPCR perspective. The highlighted epithelium, when lining a serous membrane, is called a(n) _____. Exploring GPCR-arrestin interfaces with genetically encoded crosslinkers. 33. Science 271, 363366 (1996). Y.A. J. Biol. First, when crosslinking arr2 with full-length V2R, we did find strong crosslinking hits in the 160-loop, but not in the finger loop (Supplementary Fig. Figure5df shows a modest fluctuation of 1325 degrees in the orientation during MD simulations (Supplementary Data7), with the pitch variations being themost limited by the membrane anchoring of arr2 C-edge (Supplementary Fig. However, upon closer inspe -Compact tissue is the outer layer of bones and is harder than the other layers. While the EC50 of the PTH1R-arr2 interaction remained stable, the netBRET value (fluorescence/luminescence) constantly increased with the shortening of the receptor C-tail (Supplementary Fig. While highlighting the dynamics of the PTH1R-arr2 complex, MD simulations revealed its overall stability and robust key interactions within the interface, including both at the 7TM domain and phosphorylation clusters of the C-terminal tail of PTH1R. The --- said on the subject, the better. Findings. 84, 88798882 (1987). Hits in the N-domain were clustered in the 160-loop and -strand I (Fig. Byron Almen, Dorothy Payne, Stefan Kostka, Kulik & Roberson article - Week 7 - Diversity. B) large intestine The 160-loop yielded strong crosslinks also with the phosphorylation clusters in the C-tail on the other side. 3a, Supplementary Data3, and Supplementary Figs. D) cortex. Bpa was purchased from Bachem. 2a, 3). A) pyloric sphincter ADS Identification of phosphorylation codes for arrestin recruitment by G protein-coupled receptors. Lohse, M. J. et al. Cell Sci. & MacKerell, A. D. CHARMM36 all-atom additive protein force field: Validation based on comparison to NMR data. Nucleic Acids Res. 11a, b). After 1min, signals were detected for 5min in the dark (Gbox, Syngene, Bangalore, IN). Yin, W. et al. In an 1L one-neck flask, 18.6g (48.0mmol, 1.0 eq.) 16. Start your trial now! -Recommend IT solutions as part of new projects . Each proximal tubule cell bears a brush border of . 4ae), including E391PTH1R -K77arr2 (ICL3-strand VI, Fig. The highlighted structure in the given question is adrenal gland. For illustrative purposes, a sphere is placed on C of labeled arr2 residues instead of the C where the distances are measured. B) long, spindle shaped cells with intercalated discs Chemical crosslinking pairs are grouped by PTH1R regions, namely (a) 7TM+helix VIII (res. The highlighted structure is Epididymis. This represents the first computational model of Cyc2 that accounts for the membrane microenvironment and the acidity in the extracellular matrix. performed statistical analysis of the data, all modeling and MD experiments, and interpreted results. Merkley, E. D. et al. Finger loop-depleted Bpa-arr2 were not able to capture the PTH1R, whereas the corresponding full-length Bpa-arr2 variants yielded strong crosslinking signals in the western blot. We identify 136 intermolecular proximity points that guide the construction of energy-optimized molecular models for the PTH1R-arr2 complex. -Arrestin acts as a clathrin adaptor in endocytosis of the 2 -adrenergic receptor. Seidel, L., Zarzycka, B., Katritch, V. & Coin, I. Cell 185, 16611675.e16 (2022). Biol. However, our crosslinking dataset cannot exclude an alternative situation, where residues of helix VIII lack secondary structure and are flexible. Because each crosslinking pair is identified in an independent experiment, the proximity requirements for the formation of Cys-BrEtY adduct are not expected to be all satisfied simultaneously by a single conformational snapshot of the flexible complex. The zona glomerulosa is the outermost region of the adrenal cortex and is the on . Our crosslinking data show that this segment of PTH1R comes close to the positively charged region at the distal edge of the arrestin N-domain (N-edge), comprised of the 160-loop and the loop between -strands IV and V. This arrangement is compatible with the available GPCR-arrestin structures, since the proximal GPCR C-tail is pushed away from the central crest of arrestin by the presence of the 7TM domain, so that this negatively charged region is optimally positioned to interact with the N-edge. To obtain 34, 04103, Leipzig, Germany, Division of Medicinal Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands, Department of Phar-macology, Vanderbilt University, Nashville, TN, 37232-0146, USA, Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA, You can also search for this author in Hall, M. P. et al. Nerve tissue play a major role in our body, they help in overall body . Distance restraints from crosslinking mass spectrometry: Mining a molecular dynamics simulation database to evaluate lysinelysine distances. Biol. Proc. Cells were transfected using PEI as described above. Identify the organ that contains the highlighted epithelium. Gray squares indicate crosslinking signals not significantly different from control background noise, white indicate combinations that were not tested. In the arr2, the N-terminus M1R7, C-terminus P354K358 and crest region (R51L108, P121V171, N280S320) were considered flexible. (1), where the walls of the flat bottom are set at 4.0 and at 10.2. Which organ, shown in this image, contains the highlighted epithelium? Q: Describe how we get information from the outside world into our brains. The highlighted lobe is broken down into five smaller units called ________ segments. Membranes were incubated overnight with the primary antibody at 4C under constant gentle agitation, followed by 310min washes in TBS-T. Orlando, Florida, United States. The lower bound of thecovalent diameter at 10.2 of BrEtY is drawn as a thick vertical dash line accompanied by a thin dash line at 15. Science Biology 1. Experts are tested by Chegg as specialists in their subject area. Structure of active -arrestin-1 bound to a G-protein-coupled receptor phosphopeptide. Chem. Cells were co-transfected with three plasmids: (1) 900ng of a plasmid encoding arr2-stop codon mutant, (2) 900ng of XYPylRS/4xM15-tRNA (available from ADDGENE #155343)39, and (3) 300ng of a vector encoding indicated PTH1R construct. Recently, the structures of the complexes of the full-length V2R25 and the serotonin receptor 2B26 with arr2 have been published. B) B- Expert Answer. The solution was treated with 100mL methanol and the acidic solvent was removed under reduced pressure. An initial PTHLA-PTH1R model was extracted from a cryo-EM model of thePTHLA-PTH1R-Gs complex (PDBID: 6NBF)33; missing loops and side-chains were added using loop modeling and optimization tools in ICM-Pro v.3.9.2c. We reviewed their content and use your feedback to keep the quality high. D) labia minora, Which zone of the adrenal cortex is most superficial? Chem. After 15min at 37C, the cells were irradiated with UV light in a BLX-365 crosslinker (BioBudget Technologies, Krefeld, DE; 365nm; 4 8W bulbs) for 15min on ice. Transcribed image text: Identify the highlighted structure. The highlighted structure is lined with hairs for filtering out larger particles. Afterward, 50l of 5M colenterazine dissolved in HDB were added to each well (1.67M final concentration of coelenterazine in the well). Han, M., Gurevich, V. V., Vishnivetskiy, S. A., Sigler, P. B. Recent flashcard sets. Experts are tested by Chegg as specialists in their subject area. These BrEtY-arr2 mutants were co-expressed with wt PTH1R, which carries four native Cys residues in the juxtamembrane intracellular elements (Supplementary Fig. HEK293T cells were maintained in Dulbeccos modified Eagle medium (DMEM; high glucose 4.5g/l, 4mM glutamine, pyruvate; Thermo Fisher Scientific) supplemented with 10% (v/v) fetal calf serum (FCS) (Thermo Fisher Scientific) and 100U/mL penicillin and 100g/mL streptomycin (Thermo Fisher Scientific) (full DMEM) at 37C under 5% CO2 and 95% humidity. Pharmacol. Role of beta-arrestin in mediating agonist-promoted G protein-coupled receptor internalization. The position of helix VIII was supported by several intramolecular ionic interaction with the proximal cluster at K471PTH1R-pS489PTH1R and R485PTH1R -pS489PTH1R/pS493PTH1R (Supplementary Figs. The samples were centrifuged at 16,000 g for 10min at 4C to pellet non-soluble debris, supernatants were transferred to pre-chilled tubes. Our crosslinking data follow the PTH1R C-terminus for at least 1015 residues further and reveal the existence of an interaction network of positively charged residues in the N-terminus and -helix I of arr2 (K4, K24, R99) that engage the phosphorylated S519. The 2-adrenergic receptor/arrestin complex recruits the clathrin adaptor AP-2 during endocytosis. A) moistens and warms incoming air The path of the receptor C-terminus is largely defined by the formation of an extended -sheet between -strand I of the arrestin (residues V8 to A12) and the -strand in the PTH1R C-terminus (V500S504) that overlaps with the distal phosphorylation cluster (S501T506). BMC Evol. \text { antiemetics } & \text { endoscopy } & \text { liver function tests } & \text { stool culture } \\ C) adrenal gland PubMed B) islet C) liver Ward, A. Superior articular facet or Articular surface for anterior arch of the atlas 10) Identify the foramens surrounded by the highlighted structures. C) common carotid Top (b), front (c), and back (d) views of arr2 are shown. The assembled initial models underwent an extensive energy-based Metropolis Monte Carlo (MMC) sampling in internal coordinates for 10 independent trials each of more than 2 million steps, as described in Methods47,48,52. 17a), K408PTH1R -L71arr2 and K405PTH1R -G72arr2 (TM6-finger loop, Fig. A typical plant body mainly. Abraham, M. J. et al. Pairwise C-C distances were measured; when glycine was present, C was used instead. D) uterus, A) cervix Pick 3 of the following and argue that the following are e Kim 2 This cell contains dark staining granules which obscure the nucleus. D) colloid, Patient JT's blood typing chart showed coagulation only to the anti-B serum. Proc. duodenum. Images. The highlighted structure (scrotum) contains a layer of smooth muscle that wrinkles the skin under cold conditions to help maintain the temperature of the testes. a Plot of pairwise C-C distances against chemical crosslinking yields in the PTH1R-arr2 model after flexible refinement from the M2R-arr2 template. B) rugae 19a, b), the level of strain in this region of the complex dramatically increased compared to our model (Supplementary Fig. eLife 6, e27711 (2017). -Working on Banking Domains - Loyalty, Retail, Corporate, across Geographies - Middle East, APAC, Europe. Pages 11. Solution for Identify the highlighted structure. \text { bariatric } & \text { gastroscopy } & \text { MRCP } & \text { upper Gl series } B) stomach ISSN 2041-1723 (online). https://doi.org/10.1038/s41467-023-36797-2, DOI: https://doi.org/10.1038/s41467-023-36797-2. 17, 163 (2017). Cytotechnology 62, 7382 (2010). arrow_forward Which component of the connective tissue in this field of view is highlighted? 4b). Expert Answer. The authors declare no competing interests. Identify the highlighted structures. Which of the following best describes the highlighted structure? 14, eabc5944 (2021). 2). Vilardaga, J.-P., Jean-Alphonse, F. G. & Gardella, T. J. Endosomal generation of cAMP in GPCR signaling. B) common hepatic duct After 24h, cells were trypsinized and re-seeded to PDL coated 96-wells with a density of 70,000 cells per well in FluoroBrite DMEM (Thermo Fisher Scientific, Waltham, MA). XCIII. A) external iliac Indeed, while only about half of the pairwise crosslinks strictly satisfy the 10.2 Cys-BrEtY C-C distance in the static model, most of them (96%) come within this distance at some point during unbiased MD simulations, with the six outliers coming within 15. A: Our vision of the outer world is anticipated by the human brain. The highlighted organ in the image is the Esophagus. Cells were lysed in 80L Triton lysis buffer (50mM HEPES pH 7.5, 150mM NaCl, 10% glycerol, 1% Triton X-100, 1.5mM MgCl2, 1mM EGTA, 1mM DTT and 1 protease inhibitor) for 30min on ice and vortexed every 10min. Eliminating phosphorylation sites of the parathyroid hormone receptor type 1 differentially affects stimulation of phospholipase C and receptor internalization. C) zona glomerulosa Identify the subject and verb in each sentence in the following paragraph. Curr. (g) Compass and aircraft axes to define pitch, roll, yaw angles. Start your trial now! Doc Preview. Homework help starts here! 2003-2023 Chegg Inc. All rights reserved. The highlighted structure separates the abdominal cavity from the _______ cavity. . C) hard palate Prepared material take offs for tank steel construction. 293, 55565571 (2018). D) O+, Which leukocyte is the second to least common? You'll get a detailed solution from a subject matter expert that helps you learn core concepts. -arrestin1 and 2 exhibit distinct phosphorylation-dependent conformations when coupling to the same GPCR in living cells, Allosteric interactions in the parathyroid hormone GPCRarrestin complex formation, Conformational signatures in -arrestin2 reveal natural biased agonism at a G-protein-coupled receptor, Structural studies of phosphorylation-dependent interactions between the V2R receptor and arrestin-2, Dynamics of GLP-1R peptide agonist engagement are correlated with kinetics of G protein activation, Heterotrimeric Gq proteinsact as a switch for GRK5/6 selectivity underlying -arrestin transducer bias, DeSiphering receptor core-induced and ligand-dependent conformational changes in arrestin via genetic encoded trimethylsilyl 1H-NMR probe, Molecular insights into the distinct signaling duration for the peptide-induced PTH1R activation, Molecular mechanism of GPCR-mediated arrestin activation, https://www.uniprot.org/uniprotkb/Q03431/entry#sequences, Description of Additional Supplementary Files, http://creativecommons.org/licenses/by/4.0/. Receptor-specific desensitization with purified proteins. To each well, 50l of luciferin substrate buffer (luciferase buffer supplemented with 0.3mM luciferin, 1mM ATP, 1mM DTT pH 7.8) were subsequently added by the first injector and the total luminescence was measured. A) epididymis Can you view a text file or a binary A group of cells having a similar. The highlighted structures are folds (cellular extensions) of the cell _____ membrane. To identify the captured PTH1R residue, native Cys residues in the receptor were substituted one by one with Ser, which does not react with BrEtY (Supplementary Fig. Crystal structure of rhodopsin bound to arrestin by femtosecond X-ray laser. -Su Use LEFT and RIGHT arrow keys to navigate between flashcards; Use UP and DOWN arrow keys to flip the card; What term is used to refer to the highlighted epithelium in a blood vessel? A) eosinophil Proc. Am. To assess whether the distal C-tail interacts with arr2, we generated a set of progressively shortened PTH1R variants and fused them at the C-terminus to NanoLuc (Nluc)44. performed the functional assays at PTH1R-mutants. A) deoxygenated cecum. (2), (3), (4), respectively. Structure 9, 869880 (2001). The vast majority (130 out of 136) of the crosslinked pairs came within the C-C cutoff <10.2 at some point during the MD simulations, including most of the pairs that were >15 apart in the static model (Fig. Samples were resolved on 8% Tris/glycine polyacrylamide gels and transferred to a PVDF membrane (Millipore Immobilon, Merck, pore size 0.45m). (e) $\overrightarrow{\mathbf{v}}_1$ and $\overrightarrow{\mathbf{v}}_2$ are in the same plane. The covalently linked complex was detected as a ~200kDa band on western blots, as shown previously39. Internet Explorer). Identify the highlighted structure of the lung. D) presence of microvilli, What is the function of the hilum? (b) $V_2=0$. Arrestins are cytosolic proteins that regulate signaling of nearly all G protein-coupled receptors (GPCRs)1,2. Natl Acad. 288, 25292549 (2021). United Arab Emirates. Identify the highlighted epithelial cell types. Accordingly, the C-terminally truncated PTH1R variant missing the distal cluster, but not the one missing the proximal cluster, showed impaired arrestin recruitment in our BRET assay (Supplementary Fig. The parathyroid hormone receptorsFamily B G proteincoupled receptors. The results show that mean annual precipitation and soil pH are the major environmental factors that shape soil bacterial communities in maize soils and members of the core microbiome were more frequently found in the center of the ecosystem network compared with other taxa. Fibroblast. Bous, J. et al. V.K. Arr2 with BrEtY at six positions located in the finger loop (T58, E66, F75, D78), the middle loop (T136) and the 160-loop (E155) yielded the strongest signals. The proposed model offers several improvements over the existing joint independent component analysis (jICA) model. 18c) and with our PTH1R-arr2 model. Indrischek, H., Prohaska, S. J., Gurevich, V. V., Gurevich, E. V. & Stadler, P. F. Uncovering missing pieces: duplication and deletion history of arrestins in deuterostomes. Nat. and Y.A. Aydin, Y., Bttke, T., Lam, J.H. CAS and JavaScript. C) insertion of chief cells The last PTH1R residue involved in a crosslinking pair was P524. Led team of 5 professionals. Which letter corresponds to the organ that makes bile? Although the interactions can switch between several positively charged side-chains of arr2 in the model, this position well satisfies other crosslinking proximity restraints and might contribute to the overall complex stability (Fig. Identify the highlighted structure. J.H.L. This suggests that the 160-loop of arr2 is dynamically sandwiched between ICL3 and the C-tail of the receptor, which probably contributes to the stabilization of the overall organization of the complex. By combining systematic crosslinking in a cellular environment with extensive molecular modeling and MD simulations, we obtained unique insights into the complex of arr2 with the PTH1R, a prototypical class B GPCR and a major clinical target. ADS Revise the following paragraph to 5 Identify the highlighted structure 6 Identify the. A) cystic duct To suppress interference by crosslinking with endogenous Cys in PTH1R, C217 or C397 were substituted by Ser in some blocks. Sci. View the full answer. C) bladder Ed. Zhou, X. E. et al. In the highlighted structure, which cell types produce testosterone? Fredriksson, R., Lagerstrm, M. C., Lundin, L.-G. & Schith, H. B. 5ac, Supplementary Data46). The accurate assignment of water molecules, magnesium and potassium ions in our model highlights the fundamental biological role of ribosomal RNA . Google Scholar. For glycine, C was used instead of C. The flexible ICL3 is usually missing in GPCR-arr2 and in most structures of G protein-bound GPCRs, including the PTH1R-Gscomplex.