AT1 Receptor Induced Alterations in Histone H2A Reveal Novel Insights into GPCR Control of Chromatin Remodeling

Chronic activation of angiotensin II (AngII) type 1 receptor (AT1R), a prototypical G protein-coupled receptor (GPCR) induces gene regulatory stress which is responsible for phenotypic modulation of target cells. The AT1R-selective drugs reverse the gene regulatory stress in various cardiovascular diseases. However, the molecular mechanisms are not clear. We speculate that activation states of AT1R modify the composition of histone isoforms and post-translational modifications (PTM), thereby alter the structure-function dynamics of chromatin. We combined total histone isolation, FPLC separation, and mass spectrometry techniques to analyze histone H2A in HEK293 cells with and without AT1R activation. We have identified eight isoforms: H2AA, H2AG, H2AM, H2AO, H2AQ, Q96QV6, H2AC and H2AL. The isoforms, H2AA, H2AC and H2AQ were methylated and H2AC was phosphorylated. The relative abundance of specific H2A isoforms and PTMs were further analyzed in relationship to the activation states of AT1R by immunochemical studies. Within 2 hr, the isoforms, H2AA/O exchanged with H2AM. The monomethylated H2AC increased rapidly and the phosphorylated H2AC decreased, thus suggesting that enhanced H2AC methylation is coupled to Ser1p dephosphorylation. We show that H2A125Kme1 promotes interaction with the heterochromatin associated protein, HP1α. These specific changes in H2A are reversed by treatment with the AT1R specific inhibitor losartan. Our analysis provides a first step towards an awareness of histone code regulation by GPCRs

Manifold active-state conformations in GPCRs: Agonist-activated constitutively active mutant AT1 receptor preferentially couples to Gq compared to the wild-type AT1 receptor

AbstractThe angiotensin II type I (AT1) receptor mediates regulation of blood pressure and water-electrolyte balance by Ang II. Substitution of Gly for Asn111 of the AT1 receptor constitutively activates the receptor leading to Gq-coupled IP3 production independent of Ang II binding. The Ang II-activated conformation of the AT1N111G receptor was proposed to be similar to that of the wild-type AT1 receptor, although, various aspects of the Ang II-induced conformation of this constitutively active mutant receptor have not been systematically studied. Here, we provide evidence that the conformation of the active state of the wild-type and the constitutively active AT1 receptors are different. Upon Ang II binding an activated conformation of the wild-type AT1 receptor activates G protein and recruits β-arrestin. In contrast, the agonist-bound AT1N111G mutant receptor preferentially couples to Gq and is inadequate in β-arrestin recruitment

Penerapan Metode Eksperimen untuk Meningkatkan Konsep Dasar Sains pada Anak Didik Kelompok A Tk Pkk Suruhwadang Kecamatan Kademangan Kabupaten Blitar

Tujuan penelitian ini adalah untuk memperoleh tentang kemampuan kognitif anak dalamhal konsep dasar sains dengan menggunakan metode eksperimen pada anak didik kelompokA TK PKK Suruhwadang sebelum dan sesudah dilakukan tindakan. Melakukan tindakanberupa penerapan metode eksperimen untuk meningkatkan kemampuan kognitif dalamkonsep dasar sains pada anak didik kelompok A TK PKK Suruhwadang. Mengetahui adatidaknya perbedaan kemampuan konsep dasar sains dengan menggunakan metodeeksperimen pada anak didik kelompok A TK PKK Suruhwadang antara sebelum dan setelahdilakukan tindakan. Rumusan masalah pada penitilian ini adalah apakah metode eksperimendapat meningkatkan kemampuan pemahaman konsep dasar sains pada anak didik kelompokA TK PKK Suruhwadang Kecamatan Kademangan Kabupaten Blitar. Untuk menjawabrumusan masalah digunakan jenis penelitian tindakan kelas (PTK) dengan model Kemmisdan Taggart melalui empat tahapan yaitu tahap perencanaan , pelaksanaan, observasi danrefleksiyang dilalui dengan dua siklus. Teknik pengumpulan data menggunakan teknikobservasi dan dokumentasi. Adapun instrumen yang digunakan adalah lembar observasikegiatan anak dan lembar observasi pembelajaran oleh guru.Hasil penelitian menunjukanbahwa kemampuan kognitif anak kelompok A pada konsep dasar sain pada pra penelitianmenunjukkan prosentase 56.25%. Setelah pelaksanaan siklus I tentang bidang kemampuankognitif pada konsep dasar sains menunjukkan 59% mengalami peningkatan .Setelahpelaksanaan siklus ke II naik menjadi 83%. Hal ini menunjukkan pelaksanaan siklus ke IItelah mencapai kriteria ketuntasan dan membuktikan bahwa dengan metode eksperimendapat meningkatkan kemampuan kognitif dalam konsep dasar sains

Angiotensin receptors in GtoPdb v.2023.1

The actions of angiotensin II (Ang II) are mediated by AT1 and AT2 receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Angiotensin receptors [63, 155]), which have around 30% sequence similarity. The decapeptide angiotensin I, the octapeptide angiotensin II and the heptapeptide angiotensin III are endogenous ligands. losartan, candesartan, olmesartan, telmisartan, etc. are clinically used AT1 receptor blockers

Angiotensin receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

The actions of angiotensin II (Ang II) are mediated by AT1 and AT2 receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Angiotensin receptors [61, 152]), which have around 30% sequence similarity. The decapeptide angiotensin I, the octapeptide angiotensin II and the heptapeptide angiotensin III are endogenous ligands. losartan, candesartan, telmisartan, etc. are clinically used AT1 receptor blockers

High throughput mutagenesis for identification of residues regulating human prostacyclin (hIP) receptor

The human prostacyclin receptor (hIP receptor) is a seven-transmembrane G protein-coupled receptor (GPCR) that plays a critical role in vascular smooth muscle relaxation and platelet aggregation. hIP receptor dysfunction has been implicated in numerous cardiovascular abnormalities, including myocardial infarction, hypertension, thrombosis and atherosclerosis. Genomic sequencing has discovered several genetic variations in the PTGIR gene coding for hIP receptor, however, its structure-function relationship has not been sufficiently explored. Here we set out to investigate the applicability of high throughput random mutagenesis to study the structure-function relationship of hIP receptor. While chemical mutagenesis was not suitable to generate a mutagenesis library with sufficient coverage, our data demonstrate error-prone PCR (epPCR) mediated mutagenesis as a valuable method for the unbiased screening of residues regulating hIP receptor function and expression. Here we describe the generation and functional characterization of an epPCR derived mutagenesis library compromising >4000 mutants of the hIP receptor. We introduce next generation sequencing as a useful tool to validate the quality of mutagenesis libraries by providing information about the coverage, mutation rate and mutational bias. We identified 18 mutants of the hIP receptor that were expressed at the cell surface, but demonstrated impaired receptor function. A total of 38 non-synonymous mutations were identified within the coding region of the hIP receptor, mapping to 36 distinct residues, including several mutations previously reported to affect the signaling of the hIP receptor. Thus, our data demonstrates epPCR mediated random mutagenesis as a valuable and practical method to study the structurefunction relationship of GPCRs. © 2014 Bill et al

Class A Orphans (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Table 1 lists a number of putative GPCRs identified by NC-IUPHAR [191], for which preliminary evidence for an endogenous ligand has been published, or for which there exists a potential link to a disease, or disorder. These GPCRs have recently been reviewed in detail [148]. The GPCRs in Table 1 are all Class A, rhodopsin-like GPCRs. Class A orphan GPCRs not listed in Table 1 are putative GPCRs with as-yet unidentified endogenous ligands.Table 1: Class A orphan GPCRs with putative endogenous ligands GPR3GPR4GPR6GPR12GPR15GPR17GPR20 GPR22GPR26GPR31GPR34GPR35GPR37GPR39 GPR50GPR63GRP65GPR68GPR75GPR84GPR87 GPR88GPR132GPR149GPR161GPR183LGR4LGR5 LGR6MAS1MRGPRDMRGPRX1MRGPRX2P2RY10TAAR2 In addition the orphan receptors GPR18, GPR55 and GPR119 which are reported to respond to endogenous agents analogous to the endogenous cannabinoid ligands have been grouped together (GPR18, GPR55 and GPR119)

Class A Orphans (version 2020.5) in the IUPHAR/BPS Guide to Pharmacology Database

Table 1 lists a number of putative GPCRs identified by NC-IUPHAR [194], for which preliminary evidence for an endogenous ligand has been published, or for which there exists a potential link to a disease, or disorder. These GPCRs have recently been reviewed in detail [150]. The GPCRs in Table 1 are all Class A, rhodopsin-like GPCRs. Class A orphan GPCRs not listed in Table 1 are putative GPCRs with as-yet unidentified endogenous ligands.Table 1: Class A orphan GPCRs with putative endogenous ligands GPR3 GPR4 GPR6 GPR12 GPR15 GPR17 GPR20 GPR22 GPR26 GPR31 GPR34 GPR35 GPR37 GPR39 GPR50 GPR63 GRP65 GPR68 GPR75 GPR84 GPR87 GPR88 GPR132 GPR149 GPR161 GPR183 LGR4 LGR5 LGR6 MAS1 MRGPRD MRGPRX1 MRGPRX2 P2RY10 TAAR2 In addition the orphan receptors GPR18, GPR55 and GPR119 which are reported to respond to endogenous agents analogous to the endogenous cannabinoid ligands have been grouped together (GPR18, GPR55 and GPR119)