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Prüschenk S, Majer M, Schlossmann J. Novel Functional Features of cGMP Substrate Proteins IRAG1 and IRAG2. Int J Mol Sci 2023; 24:9837. [PMID: 37372987 DOI: 10.3390/ijms24129837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
The inositol triphosphate-associated proteins IRAG1 and IRAG2 are cGMP kinase substrate proteins that regulate intracellular Ca2+. Previously, IRAG1 was discovered as a 125 kDa membrane protein at the endoplasmic reticulum, which is associated with the intracellular Ca2+ channel IP3R-I and the PKGIβ and inhibits IP3R-I upon PKGIβ-mediated phosphorylation. IRAG2 is a 75 kDa membrane protein homolog of IRAG1 and was recently also determined as a PKGI substrate. Several (patho-)physiological functions of IRAG1 and IRAG2 were meanwhile elucidated in a variety of human and murine tissues, e.g., of IRAG1 in various smooth muscles, heart, platelets, and other blood cells, of IRAG2 in the pancreas, heart, platelets, and taste cells. Hence, lack of IRAG1 or IRAG2 leads to diverse phenotypes in these organs, e.g., smooth muscle and platelet disorders or secretory deficiency, respectively. This review aims to highlight the recent research regarding these two regulatory proteins to envision their molecular and (patho-)physiological tasks and to unravel their functional interplay as possible (patho-)physiological counterparts.
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Affiliation(s)
- Sally Prüschenk
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Regensburg, 93040 Regensburg, Germany
| | - Michael Majer
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Regensburg, 93040 Regensburg, Germany
| | - Jens Schlossmann
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Regensburg, 93040 Regensburg, Germany
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Sharma R, Kim JJ, Qin L, Henning P, Akimoto M, VanSchouwen B, Kaur G, Sankaran B, MacKenzie KR, Melacini G, Casteel DE, Herberg FW, Kim CW. An auto-inhibited state of protein kinase G and implications for selective activation. eLife 2022; 11:79530. [PMID: 35929723 PMCID: PMC9417419 DOI: 10.7554/elife.79530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 08/04/2022] [Indexed: 11/29/2022] Open
Abstract
Cyclic GMP-dependent protein kinases (PKGs) are key mediators of the nitric oxide/cyclic guanosine monophosphate (cGMP) signaling pathway that regulates biological functions as diverse as smooth muscle contraction, cardiac function, and axon guidance. Understanding how cGMP differentially triggers mammalian PKG isoforms could lead to new therapeutics that inhibit or activate PKGs, complementing drugs that target nitric oxide synthases and cyclic nucleotide phosphodiesterases in this signaling axis. Alternate splicing of PRKG1 transcripts confers distinct leucine zippers, linkers, and auto-inhibitory (AI) pseudo-substrate sequences to PKG Iα and Iβ that result in isoform-specific activation properties, but the mechanism of enzyme auto-inhibition and its alleviation by cGMP is not well understood. Here, we present a crystal structure of PKG Iβ in which the AI sequence and the cyclic nucleotide-binding (CNB) domains are bound to the catalytic domain, providing a snapshot of the auto-inhibited state. Specific contacts between the PKG Iβ AI sequence and the enzyme active site help explain isoform-specific activation constants and the effects of phosphorylation in the linker. We also present a crystal structure of a PKG I CNB domain with an activating mutation linked to Thoracic Aortic Aneurysms and Dissections. Similarity of this structure to wildtype cGMP-bound domains and differences with the auto-inhibited enzyme provide a mechanistic basis for constitutive activation. We show that PKG Iβ auto-inhibition is mediated by contacts within each monomer of the native full-length dimeric protein, and using the available structural and biochemical data we develop a model for the regulation and cooperative activation of PKGs.
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Affiliation(s)
- Rajesh Sharma
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, United States
| | - Jeong Joo Kim
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, United States
| | - Liying Qin
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, United States
| | - Philipp Henning
- Department of Biochemistry, University of Kassel, kassel, Germany
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Ontario, Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Ontario, Canada
| | - Gundeep Kaur
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, United States
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Kevin R MacKenzie
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, United States
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Fritz W Herberg
- Department of Biochemistry, University of Kassel, kassel, Germany
| | - Choel W Kim
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, United States
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Prüschenk S, Schlossmann J. Function of IRAG2 Is Modulated by NO/cGMP in Murine Platelets. Int J Mol Sci 2022; 23:ijms23126695. [PMID: 35743138 PMCID: PMC9223716 DOI: 10.3390/ijms23126695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/08/2022] [Accepted: 06/14/2022] [Indexed: 01/27/2023] Open
Abstract
Inositol 1,4,5-triphosphate receptor-associated 2 (IRAG2) is a type II membrane protein located at the endoplasmic reticulum. It is a homologue of inositol 1,4,5-triphosphate receptor-associated cGMP kinase substrate 1 (IRAG1), a substrate protein of cGMP-dependent protein kinase I (PKGI), and is among others expressed in platelets. Here, we studied if IRAG2 is also located in platelets and might be a substrate protein of PKGI. IRAG2 was detected in platelets of IRAG2-WT animals but not in those of IRAG2-KO animals. Next, we validated by co-immunoprecipitation studies that IRAG2 is associated with IP3R1-3. No direct stable interaction with PKGIβ or with IRAG1 was observed. Phosphorylation of IRAG2 in murine platelets using a Ser/Thr-specific phospho-antibody was found in vitro and ex vivo upon cGMP stimulation. To gain insight into the function of IRAG2, platelet aggregation studies were performed using thrombin and collagen as agonists for treatment of isolated IRAG2-WT or IRAG2-KO platelets. Interestingly, platelet aggregation was reduced in the absence of IRAG2. Pretreatment of wild type or IRAG2-KO platelets with sodium nitroprusside (SNP) or 8-pCPT-cGMP revealed a further reduction in platelet aggregation in the absence of IRAG2. These results show that IRAG2 is a substrate of PKGI in murine platelets. Furthermore, our results indicate that IRAG2 is involved in the induction of thrombin- or collagen-induced platelet aggregation and that this effect is enhanced by cGMP-dependent phosphorylation of IRAG2. As IRAG1 was previously shown to inhibit platelet aggregation in a cGMP-dependent manner, it can be speculated that IRAG2 exerts an opposing function and might be an IRAG1 counterpart in murine platelets.
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Koehler K, Hmida D, Schlossmann J, Landgraf D, Reisch N, Schuelke M, Huebner A. Homozygous mutation in murine retrovirus integration site 1 gene associated with a non-syndromic form of isolated familial achalasia. Neurogastroenterol Motil 2020; 32:e13923. [PMID: 32573102 DOI: 10.1111/nmo.13923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/18/2020] [Accepted: 05/25/2020] [Indexed: 01/23/2023]
Abstract
BACKGROUND Achalasia is a condition characterized by impaired function of esophageal motility and incomplete relaxation of the lower esophagus sphincter, causing dysphagia and regurgitation. Rare cases of early-onset achalasia appear often in combination with further symptoms in a syndromic form as an inherited disease. METHODS Whole genome sequencing was used to investigate the genetic basis of isolated achalasia in a family of Tunisian origin. We analyzed the function of the affected protein with immunofluorescence and affinity chromatography study. KEY RESULTS A homozygous nonsense mutation was detected in murine retrovirus integration site 1 (MRVI1) gene (Human Genome Organisation Gene Nomenclature Committee (HGNC) approved gene symbol: IRAG1) encoding the inositol 1,4,5-trisphosphate receptor 1 (IP3 R1)-associated cyclic guanosine monophosphate (cGMP) kinase substrate (IRAG). Sanger sequencing confirmed co-segregation of the mutation with the disease. Sequencing of the entire MRVI1 gene in 35 additional patients with a syndromic form of achalasia did not uncover further cases with MRVI1 mutations. Immunofluorescence analysis of transfected COS7 cells revealed GFP-IRAG with the truncating mutation p.Arg112* (transcript variant 1) or p.Arg121* (transcript variant 2) to be mislocalized in the cytoplasm and the nucleus. Co-transfection with cGMP-dependent protein kinase 1 isoform β (cGK1β) depicted a partial mislocalization of cGK1β due to mislocalized truncated IRAG. Isolation of protein complexes revealed that the truncation of this protein causes the loss of the interaction domain of IRAG with cGK1β. CONCLUSIONS & INFERENCES In individuals with an early onset of achalasia without further accompanying symptoms, MRVI1 mutations should be considered as the disease-causing defect.
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Affiliation(s)
- Katrin Koehler
- Medizinische Fakultät Carl Gustav Carus, Children's Hospital, Technische Universität Dresden, Dresden, Germany
| | - Dorra Hmida
- Department of Medical Genetics, Anatomy and Cytology, Farhat Hached Hospital, Sousse, Tunisia
| | - Jens Schlossmann
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Regensburg, Regensburg, Germany
| | - Dana Landgraf
- Medizinische Fakultät Carl Gustav Carus, Children's Hospital, Technische Universität Dresden, Dresden, Germany
| | - Nicole Reisch
- Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Markus Schuelke
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Angela Huebner
- Medizinische Fakultät Carl Gustav Carus, Children's Hospital, Technische Universität Dresden, Dresden, Germany
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Beyer T, Klose F, Kuret A, Hoffmann F, Lukowski R, Ueffing M, Boldt K. Tissue- and isoform-specific protein complex analysis with natively processed bait proteins. J Proteomics 2020; 231:103947. [PMID: 32853754 DOI: 10.1016/j.jprot.2020.103947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/20/2020] [Accepted: 08/09/2020] [Indexed: 12/11/2022]
Abstract
Protein-protein interaction analysis is an important tool to elucidate the function of proteins and protein complexes as well as their dynamic behavior. To date, the analysis of tissue- or even cell- or compartment-specific protein interactions is still relying on the availability of specific antibodies suited for immunoprecipitation. Here, we aimed at establishing a method that allows identification of protein interactions and complexes from intact tissues independent of specific, high affinity antibodies used for protein pull-down and isolation. Tagged bait proteins were expressed in human HEK293T cells and residual interactors removed by SDS. The resulting tag-fusion protein was then used as bait to pull proteins from tissue samples. Tissue-specific interactions were reproducibly identified from porcine retina as well as from retinal pigment epithelium using the ciliary protein lebercilin as bait. Further, murine heart-specific interactors of two gene products of the 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase type 1 (cGK1) were investigated. Here, specific interactions were associated with the cGK1α and β gene products, that differ only in their unique amino-terminal region comprising about 100 aa. As such, the new protocol provides a fast and reliable method for tissue-specific protein complex analysis which is independent of the availability or suitability of antibodies for immunoprecipitation. SIGNIFICANCE: Protein-protein interaction in the functional relevant tissue is still difficult due to the dependence on specific antibodies or bait production in bacteria or insect cells. Here, the tagged protein of interest is produced in a human cell line and bound proteins are gently removed using SDS. Because applying the suitable SDS concentration is a critical step, different SDS solutions were tested to demonstrate their influence on interactions and the clean-up process. The established protocol enabled a tissue-specific analysis of the ciliary proteins lebercilin and TMEM107 using pig eyes. In addition, two gene products of the 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase type 1 showed distinct protein interactions in mouse heart tissue. With the easy, fast and cheap protocol presented here, deep insights in tissue-specific and functional relevant protein complex formation is possible.
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Affiliation(s)
- Tina Beyer
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Strasse 7, D-72076 Tuebingen, Germany
| | - Franziska Klose
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Strasse 7, D-72076 Tuebingen, Germany
| | - Anna Kuret
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Auf der Morgenstelle 8, D-72076 Tuebingen, Germany
| | - Felix Hoffmann
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Strasse 7, D-72076 Tuebingen, Germany
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tuebingen, Auf der Morgenstelle 8, D-72076 Tuebingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Strasse 7, D-72076 Tuebingen, Germany.
| | - Karsten Boldt
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Strasse 7, D-72076 Tuebingen, Germany.
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6
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cGMP signalling in cardiomyocyte microdomains. Biochem Soc Trans 2020; 47:1327-1339. [PMID: 31652306 DOI: 10.1042/bst20190225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/20/2019] [Accepted: 09/24/2019] [Indexed: 02/07/2023]
Abstract
3',5'-Cyclic guanosine monophosphate (cGMP) is one of the major second messengers critically involved in the regulation of cardiac electrophysiology, hypertrophy, and contractility. Recent molecular and cellular studies have significantly advanced our understanding of the cGMP signalling cascade, its local microdomain-specific regulation and its role in protecting the heart from pathological stress. Here, we summarise recent findings on cardiac cGMP microdomain regulation and discuss their potential clinical significance.
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7
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Sheehe JL, Bonev AD, Schmoker AM, Ballif BA, Nelson MT, Moon TM, Dostmann WR. Oxidation of cysteine 117 stimulates constitutive activation of the type Iα cGMP-dependent protein kinase. J Biol Chem 2018; 293:16791-16802. [PMID: 30206122 DOI: 10.1074/jbc.ra118.004363] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/04/2018] [Indexed: 12/22/2022] Open
Abstract
The type I cGMP-dependent protein kinase (PKG I) is an essential regulator of vascular tone. It has been demonstrated that the type Iα isoform can be constitutively activated by oxidizing conditions. However, the amino acid residues implicated in this phenomenon are not fully elucidated. To investigate the molecular basis for this mechanism, we studied the effects of oxidation using recombinant WT, truncated, and mutant constructs of PKG I. Using an in vitro assay, we observed that oxidation with hydrogen peroxide (H2O2) resulted in constitutive, cGMP-independent activation of PKG Iα. PKG Iα C42S and a truncation construct that does not contain Cys-42 (Δ53) were both constitutively activated by H2O2 In contrast, oxidation of PKG Iα C117S maintained its cGMP-dependent activation characteristics, although oxidized PKG Iα C195S did not. To corroborate these results, we also tested the effects of our constructs on the PKG Iα-specific substrate, the large conductance potassium channel (KCa 1.1). Application of WT PKG Iα activated by either cGMP or H2O2 increased the open probabilities of the channel. Neither cGMP nor H2O2 activation of PKG Iα C42S significantly increased channel open probabilities. Moreover, cGMP-stimulated PKG Iα C117S increased KCa 1.1 activity, but this effect was not observed under oxidizing conditions. Finally, we observed that PKG Iα C42S caused channel flickers, indicating dramatically altered KCa 1.1 channel characteristics compared with channels exposed to WT PKG Iα. Cumulatively, these results indicate that constitutive activation of PKG Iα proceeds through oxidation of Cys-117 and further suggest that the formation of a sulfur acid is necessary for this phenotype.
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Affiliation(s)
- Jessica L Sheehe
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Adrian D Bonev
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Anna M Schmoker
- the Department of Biology, University of Vermont, Burlington, Vermont 05405 and
| | - Bryan A Ballif
- the Department of Biology, University of Vermont, Burlington, Vermont 05405 and
| | - Mark T Nelson
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Thomas M Moon
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
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8
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Moon TM, Sheehe JL, Nukareddy P, Nausch LW, Wohlfahrt J, Matthews DE, Blumenthal DK, Dostmann WR. An N-terminally truncated form of cyclic GMP-dependent protein kinase Iα (PKG Iα) is monomeric and autoinhibited and provides a model for activation. J Biol Chem 2018; 293:7916-7929. [PMID: 29602907 DOI: 10.1074/jbc.ra117.000647] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/26/2018] [Indexed: 01/08/2023] Open
Abstract
The type I cGMP-dependent protein kinases (PKG I) serve essential physiological functions, including smooth muscle relaxation, cardiac remodeling, and platelet aggregation. These enzymes form homodimers through their N-terminal dimerization domains, a feature implicated in regulating their cooperative activation. Previous investigations into the activation mechanisms of PKG I isoforms have been largely influenced by structures of the cAMP-dependent protein kinase (PKA). Here, we examined PKG Iα activation by cGMP and cAMP by engineering a monomeric form that lacks N-terminal residues 1-53 (Δ53). We found that the construct exists as a monomer as assessed by whole-protein MS, size-exclusion chromatography, and small-angle X-ray scattering (SAXS). Reconstruction of the SAXS 3D envelope indicates that Δ53 has a similar shape to the heterodimeric RIα-C complex of PKA. Moreover, we found that the Δ53 construct is autoinhibited in its cGMP-free state and can bind to and be activated by cGMP in a manner similar to full-length PKG Iα as assessed by surface plasmon resonance (SPR) spectroscopy. However, we found that the Δ53 variant does not exhibit cooperative activation, and its cyclic nucleotide selectivity is diminished. These findings support a model in which, despite structural similarities, PKG Iα activation is distinct from that of PKA, and its cooperativity is driven by in trans interactions between protomers.
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Affiliation(s)
- Thomas M Moon
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405.
| | - Jessica L Sheehe
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Praveena Nukareddy
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405
| | - Lydia W Nausch
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Jessica Wohlfahrt
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Dwight E Matthews
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112
| | - Wolfgang R Dostmann
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405.
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9
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Roy AL. Pathophysiology of TFII-I: Old Guard Wearing New Hats. Trends Mol Med 2017; 23:501-511. [PMID: 28461154 DOI: 10.1016/j.molmed.2017.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/30/2017] [Accepted: 04/05/2017] [Indexed: 12/23/2022]
Abstract
The biochemical properties of the signal-induced multifunctional transcription factor II-I (TFII-I) indicate that it is involved in a variety of gene regulatory processes. Although gene ablation in murine models and cell-based assays show that it is encoded by an essential gene, GTF2I/Gtf2i, its physiologic role in human disorders was relatively unknown until recently. Novel studies show that it is involved in an array of human diseases including neurocognitive disorders, systemic lupus erythematosus (SLE), and cancer. Here I bring together these diverse observations to illustrate its multiple pathophysiologic functions and further conjecture on how these could be related to its known biochemical properties. I expect that a better understanding of these 'structure-function' relationships would lead to future diagnostic and/or therapeutic potential.
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Affiliation(s)
- Ananda L Roy
- Laboratory of Molecular Biology and Immunology, Biomedical Research Center, National Institutes of Health/National Institute on Aging, 251 Bayview Blvd, Baltimore, MD 21224, USA.
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10
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Qin L, Reger AS, Guo E, Yang MP, Zwart P, Casteel DE, Kim C. Structures of cGMP-Dependent Protein Kinase (PKG) Iα Leucine Zippers Reveal an Interchain Disulfide Bond Important for Dimer Stability. Biochemistry 2015; 54:4419-22. [PMID: 26132214 DOI: 10.1021/acs.biochem.5b00572] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
cGMP-dependent protein kinase (PKG) Iα is a central regulator of smooth muscle tone and vasorelaxation. The N-terminal leucine zipper (LZ) domain dimerizes and targets PKG Iα by interacting with G-kinase-anchoring proteins. The PKG Iα LZ contains C42 that is known to form a disulfide bond upon oxidation and to activate PKG Iα. To understand the molecular details of the PKG Iα LZ and C42-C42' disulfide bond, we determined crystal structures of the PKG Iα wild-type (WT) LZ and C42L LZ. Our data demonstrate that the C42-C42' disulfide bond dramatically stabilizes PKG Iα and that the C42L mutant mimics the oxidized WT LZ structurally.
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Affiliation(s)
| | | | | | | | - Peter Zwart
- ⊥Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Darren E Casteel
- @Department of Medicine, University of California at San Diego, La Jolla, California 92093, United States
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11
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Kato S, Chen J, Cornog KH, Zhang H, Roberts JD. The Golgi apparatus regulates cGMP-dependent protein kinase I compartmentation and proteolysis. Am J Physiol Cell Physiol 2015; 308:C944-58. [PMID: 25855081 DOI: 10.1152/ajpcell.00199.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 03/31/2015] [Indexed: 01/12/2023]
Abstract
cGMP-dependent protein kinase I (PKGI) is an important effector of cGMP signaling that regulates vascular smooth muscle cell (SMC) phenotype and proliferation. PKGI has been detected in the perinuclear region of cells, and recent data indicate that proprotein convertases (PCs) typically resident in the Golgi apparatus (GA) can stimulate PKGI proteolysis and generate a kinase fragment that localizes to the nucleus and regulates gene expression. However, the role of the endomembrane system in PKGI compartmentation and processing is unknown. Here, we demonstrate that PKGI colocalizes with endoplasmic reticulum (ER), ER-Golgi intermediate compartment, GA cisterna, and trans-Golgi network proteins in pulmonary artery SMC and cell lines. Moreover, PKGI localizes with furin, a trans-Golgi network-resident PC known to cleave PKGI. ER protein transport influences PKGI localization because overexpression of a constitutively inactive Sar1 transgene caused PKGI retention in the ER. Additionally, PKGI appears to reside within the GA because PKGI immunoreactivity was determined to be resistant to cytosolic proteinase K treatment in live cells. The GA appears to play a role in PKGI proteolysis because overexpression of inositol 1,4,5-trisphosphate receptor-associated cGMP kinase substrate, not only tethered heterologous PKGI-β to the ER and decreased its localization to the GA, but also diminished PKGI proteolysis and nuclear translocation. Also, inhibiting intra-GA protein transport with monensin was observed to decrease PKGI cleavage. These studies detail a role for the endomembrane system in regulating PKGI compartmentation and proteolysis. Moreover, they support the investigation of mechanisms regulating PKGI-dependent nuclear cGMP signaling in the pulmonary vasculature with Golgi dysfunction.
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Affiliation(s)
- Shin Kato
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Jingsi Chen
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | | | - Huili Zhang
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Jesse D Roberts
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts; Departments of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Cambridge, Massachusetts;
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12
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Corradini E, Burgers PP, Plank M, Heck AJR, Scholten A. Huntingtin-associated protein 1 (HAP1) is a cGMP-dependent kinase anchoring protein (GKAP) specific for the cGMP-dependent protein kinase Iβ isoform. J Biol Chem 2015; 290:7887-96. [PMID: 25653285 DOI: 10.1074/jbc.m114.622613] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Protein-protein interactions are important in providing compartmentalization and specificity in cellular signal transduction. Many studies have hallmarked the well designed compartmentalization of the cAMP-dependent protein kinase (PKA) through its anchoring proteins. Much less data are available on the compartmentalization of its closest homolog, cGMP-dependent protein kinase (PKG), via its own PKG anchoring proteins (GKAPs). For the enrichment, screening, and discovery of (novel) PKA anchoring proteins, a plethora of methodologies is available, including our previously described chemical proteomics approach based on immobilized cAMP or cGMP. Although this method was demonstrated to be effective, each immobilized cyclic nucleotide did not discriminate in the enrichment for either PKA or PKG and their secondary interactors. Hence, with PKG signaling components being less abundant in most tissues, it turned out to be challenging to enrich and identify GKAPs. Here we extend this cAMP-based chemical proteomics approach using competitive concentrations of free cyclic nucleotides to isolate each kinase and its secondary interactors. Using this approach, we identified Huntingtin-associated protein 1 (HAP1) as a putative novel GKAP. Through sequence alignment with known GKAPs and secondary structure prediction analysis, we defined a small sequence domain mediating the interaction with PKG Iβ but not PKG Iα. In vitro binding studies and site-directed mutagenesis further confirmed the specificity and affinity of HAP1 binding to the PKG Iβ N terminus. These data fully support that HAP1 is a GKAP, anchoring specifically to the cGMP-dependent protein kinase isoform Iβ, and provide further evidence that also PKG spatiotemporal signaling is largely controlled by anchoring proteins.
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Affiliation(s)
- Eleonora Corradini
- From the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Science Faculty, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands and Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Pepijn P Burgers
- From the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Science Faculty, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands and Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Michael Plank
- From the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Science Faculty, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands and Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Albert J R Heck
- From the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Science Faculty, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands and Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Arjen Scholten
- From the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Science Faculty, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands and Netherlands Proteomics Centre, Padualaan 8, 3584 CH Utrecht, The Netherlands
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13
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Reger AS, Yang MP, Koide-Yoshida S, Guo E, Mehta S, Yuasa K, Liu A, Casteel DE, Kim C. Crystal structure of the cGMP-dependent protein kinase II leucine zipper and Rab11b protein complex reveals molecular details of G-kinase-specific interactions. J Biol Chem 2014; 289:25393-403. [PMID: 25070890 DOI: 10.1074/jbc.m114.575894] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
cGMP-dependent protein kinase (PKG)-interacting proteins (GKIPs) mediate cellular targeting of PKG isoforms by interacting with their leucine zipper (LZ) domains. These interactions prevent aberrant signaling cross-talk between different PKG isotypes. To gain detailed insight into isotype-specific GKIP recognition by PKG, we analyzed the type II PKG leucine zipper domain and found that residues 40-83 dimerized and specifically interacted with Rab11b. Next, we determined a crystal structure of the PKG II LZ-Rab11b complex. The PKG II LZ domain presents a mostly nonpolar surface onto which Rab11b docks, through van der Waals interactions. Contact surfaces in Rab11b are found in switch I and II, interswitch, and the β1/N-terminal regions. This binding surface dramatically differs from that seen in the Rab11 family of interacting protein complex structures. Structural comparison with PKG Iα and Iβ LZs combined with mutagenic analysis reveals that GKIP recognition is mediated through surface charge interactions.
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Affiliation(s)
- Albert S Reger
- From the Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030
| | | | - Shizuyo Koide-Yoshida
- the Department of Biological Science and Technology, University of Tokushima Graduate School, Tokushima 770-8506, Japan
| | - Elaine Guo
- Chemistry, Rice University, Houston, Texas 77005
| | - Shrenik Mehta
- From the Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030
| | - Keizo Yuasa
- the Department of Biological Science and Technology, University of Tokushima Graduate School, Tokushima 770-8506, Japan
| | - Alan Liu
- the Department of Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Darren E Casteel
- the Department of Medicine, University of California at San Diego, La Jolla, California 92093, and
| | - Choel Kim
- From the Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030, the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
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14
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Casteel DE, Schwappacher R, Rangaswami H, Su-Yuo J. cGMP-dependent protein kinase Iβ phosphorylates and regulates the function of the actin/myosin-associatedprotein caldesmon. BMC Pharmacol Toxicol 2013. [PMCID: PMC3765506 DOI: 10.1186/2050-6511-14-s1-p13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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15
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Zhou L, Hosohata K, Gao S, Gu Z, Wang Z. cGMP-dependent protein kinase Iβ interacts with p44/WDR77 to regulate androgen receptor-driven gene expression. PLoS One 2013; 8:e63119. [PMID: 23755100 PMCID: PMC3670919 DOI: 10.1371/journal.pone.0063119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 03/28/2013] [Indexed: 01/22/2023] Open
Abstract
The androgen receptor (AR) pathway plays critical roles in controlling differentiation and proliferation of prostate epithelial cells. We previously identified a novel AR cofactor, p44/WDR77, which specifically enhances AR transcriptional activity in the prostate gland and prostate cancer. To further elucidate p44/WDR77's role in the AR signaling pathway, we conducted a yeast two-hybrid screening and identified cGMP-dependent protein kinase (PKG) as a p44/WDR77-interacting protein. Further investigation by lusiferase assay and kinase assay demonstrated that PKG-Iβ physically interacted with and phosphorylated both p44 and AR and enhanced AR transactivity in synergy with p44 in an androgen- and cGMP-dependent manner. Furthermore, PKG1β expression promoted p44/WDR77 nuclear translocation and inhibited prostate cancer cell growth via G1 cell cycle arrest. Our findings characterize PKG as a novel regulator of AR-mediated transcription by enhancing AR cofactor p44/WDR77's function, which provide a novel mechanism for the growth regulation of prostate cancer cells by the androgen signaling.
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Affiliation(s)
- Liran Zhou
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
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16
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Schwappacher R, Rangaswami H, Su-Yuo J, Hassad A, Spitler R, Casteel DE. cGMP-dependent protein kinase Iβ regulates breast cancer cell migration and invasion via interaction with the actin/myosin-associated protein caldesmon. J Cell Sci 2013; 126:1626-36. [PMID: 23418348 DOI: 10.1242/jcs.118190] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The two isoforms of type I cGMP-dependent protein kinase (PKGIα and PKGIβ) differ in their first ∼100 amino acids, giving each isoform unique dimerization and autoinhibitory domains. The dimerization domains form coiled-coil structures and serve as platforms for isoform-specific protein-protein interactions. Using the PKGIβ dimerization domain as an affinity probe in a proteomic screen, we identified the actin/myosin-associated protein caldesmon (CaD) as a PKGIβ-specific binding protein. PKGIβ phosphorylated human CaD on serine 12 in vitro and in intact cells. Phosphorylation on serine 12 or mutation of serine 12 to glutamic acid (S12E) reduced the interaction between CaD and myosin IIA. Because CaD inhibits myosin ATPase activity and regulates cell motility, we examined the effects of PKGIβ and CaD on cell migration and invasion. Inhibition of the NO/cGMP/PKG pathway reduced migration and invasion of human breast cancer cells, whereas PKG activation enhanced their motility and invasion. siRNA-mediated knockdown of endogenous CaD had pro-migratory and pro-invasive effects in human breast cancer cells. Reconstituting cells with wild-type CaD slowed migration and invasion; however, CaD containing a phospho-mimetic S12E mutation failed to reverse the pro-migratory and pro-invasive activity of CaD depletion. Our data suggest that PKGIβ enhances breast cancer cell motility and invasive capacity, at least in part, by phosphorylating CaD. These findings identify a pro-migratory and pro-invasive function for PKGIβ in human breast cancer cells, suggesting that PKGIβ is a potential target for breast cancer treatment.
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Affiliation(s)
- Raphaela Schwappacher
- Department of Medicine and Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
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17
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Morgado M, Cairrão E, Santos-Silva AJ, Verde I. Cyclic nucleotide-dependent relaxation pathways in vascular smooth muscle. Cell Mol Life Sci 2012; 69:247-66. [PMID: 21947498 PMCID: PMC11115151 DOI: 10.1007/s00018-011-0815-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 08/21/2011] [Accepted: 08/23/2011] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle tone is controlled by a balance between the cellular signaling pathways that mediate the generation of force (vasoconstriction) and release of force (vasodilation). The initiation of force is associated with increases in intracellular calcium concentrations, activation of myosin light-chain kinase, increases in the phosphorylation of the regulatory myosin light chains, and actin-myosin crossbridge cycling. There are, however, several signaling pathways modulating Ca(2+) mobilization and Ca(2+) sensitivity of the contractile machinery that secondarily regulate the contractile response of vascular smooth muscle to receptor agonists. Among these regulatory mechanisms involved in the physiological regulation of vascular tone are the cyclic nucleotides (cAMP and cGMP), which are considered the main messengers that mediate vasodilation under physiological conditions. At least four distinct mechanisms are currently thought to be involved in the vasodilator effect of cyclic nucleotides and their dependent protein kinases: (1) the decrease in cytosolic calcium concentration ([Ca(2+)]c), (2) the hyperpolarization of the smooth muscle cell membrane potential, (3) the reduction in the sensitivity of the contractile machinery by decreasing the [Ca(2+)]c sensitivity of myosin light-chain phosphorylation, and (4) the reduction in the sensitivity of the contractile machinery by uncoupling contraction from myosin light-chain phosphorylation. This review focuses on each of these mechanisms involved in cyclic nucleotide-dependent relaxation of vascular smooth muscle under physiological conditions.
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Affiliation(s)
- Manuel Morgado
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Elisa Cairrão
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - António José Santos-Silva
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Ignacio Verde
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
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18
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Kryshtafovych A, Moult J, Bartual SG, Bazan JF, Berman H, Casteel DE, Christodoulou E, Everett JK, Hausmann J, Heidebrecht T, Hills T, Hui R, Hunt JF, Seetharaman J, Joachimiak A, Kennedy MA, Kim C, Lingel A, Michalska K, Montelione GT, Otero JM, Perrakis A, Pizarro JC, van Raaij MJ, Ramelot TA, Rousseau F, Tong L, Wernimont AK, Young J, Schwede T. Target highlights in CASP9: Experimental target structures for the critical assessment of techniques for protein structure prediction. Proteins 2011; 79 Suppl 10:6-20. [PMID: 22020785 PMCID: PMC3692002 DOI: 10.1002/prot.23196] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
One goal of the CASP community wide experiment on the critical assessment of techniques for protein structure prediction is to identify the current state of the art in protein structure prediction and modeling. A fundamental principle of CASP is blind prediction on a set of relevant protein targets, that is, the participating computational methods are tested on a common set of experimental target proteins, for which the experimental structures are not known at the time of modeling. Therefore, the CASP experiment would not have been possible without broad support of the experimental protein structural biology community. In this article, several experimental groups discuss the structures of the proteins which they provided as prediction targets for CASP9, highlighting structural and functional peculiarities of these structures: the long tail fiber protein gp37 from bacteriophage T4, the cyclic GMP-dependent protein kinase Iβ dimerization/docking domain, the ectodomain of the JTB (jumping translocation breakpoint) transmembrane receptor, Autotaxin in complex with an inhibitor, the DNA-binding J-binding protein 1 domain essential for biosynthesis and maintenance of DNA base-J (β-D-glucosyl-hydroxymethyluracil) in Trypanosoma and Leishmania, an so far uncharacterized 73 residue domain from Ruminococcus gnavus with a fold typical for PDZ-like domains, a domain from the phycobilisome core-membrane linker phycobiliprotein ApcE from Synechocystis, the heat shock protein 90 activators PFC0360w and PFC0270w from Plasmodium falciparum, and 2-oxo-3-deoxygalactonate kinase from Klebsiella pneumoniae.
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Affiliation(s)
- Andriy Kryshtafovych
- Genome Center, University of California-Davis, 451 Health Sciences Drive, Davis, CA 95616, USA
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19
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Abstract
Signaling by nitric oxide (NO) determines several cardiovascular functions including blood pressure regulation, cardiac and smooth muscle hypertrophy, and platelet function. NO stimulates the synthesis of cGMP by soluble guanylyl cyclases and thereby activates cGMP-dependent protein kinases (PKGs), mediating most of the cGMP functions. Hence, an elucidation of the PKG signaling cascade is essential for the understanding of the (patho)physiological aspects of NO. Several PKG signaling pathways were identified, meanwhile regulating the intracellular calcium concentration, mediating calcium desensitization or cytoskeletal rearrangement. During the last decade it emerged that the inositol trisphosphate receptor-associated cGMP-kinase substrate (IRAG), an endoplasmic reticulum-anchored 125-kDa membrane protein, is a main signal transducer of PKG activity in the cardiovascular system. IRAG interacts specifically in a trimeric complex with the PKG1β isoform and the inositol 1,4,5-trisphosphate receptor I and, upon phosphorylation, reduces the intracellular calcium release from the intracellular stores. IRAG motifs for phosphorylation and for targeting to PKG1β and 1,4,5-trisphosphate receptor I were identified by several approaches. The (patho)physiological functions for the regulation of smooth muscle contractility and the inhibition of platelet activation were perceived. In this review, the IRAG recognition, targeting, and function are summarized compared with PKG and several PKG substrates in the cardiovascular system.
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Affiliation(s)
- Jens Schlossmann
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Regensburg, Regensburg, Germany.
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20
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Lee JH, Li S, Liu T, Hsu S, Kim C, Woods VL, Casteel DE. The amino terminus of cGMP-dependent protein kinase Iβ increases the dynamics of the protein's cGMP-binding pockets. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2011; 302:44-52. [PMID: 21643460 PMCID: PMC3107041 DOI: 10.1016/j.ijms.2010.07.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The type I cGMP-dependent protein kinases play critical roles in regulating vascular tone, platelet activation and synaptic plasticity. PKG I α and PKG Iβ differ in their first ~100 amino acids giving each isoform unique dimerization and autoinhibitory domains with identical cGMP-binding pockets and catalytic domains. The N-terminal leucine zipper and autoinhibitory domains have been shown to mediate isoform specific affinity for cGMP. PKG Iα has a >10 fold higher affinity for cGMP than PKG Iβ, and PKG Iβ that is missing its leucine zipper has a three-fold decreased affinity for cGMP. The exact mechanism through which the N-terminus of PKG alters cGMP-affinity is unknown. In the present study, we have used deuterium exchange mass spectrometry to study how PKG Iβ's N-terminus affects the conformation and dynamics of its cGMP-binding pockets. We found that the N-terminus increases the rate of deuterium exchange throughout the cGMP-binding domain. Our results suggest that the N-terminus shifts the conformational dynamics of the binding pockets, leading to an "open" conformation that has an increased affinity for cGMP.
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Affiliation(s)
- Jun H. Lee
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Sheng Li
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Tong Liu
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Simon Hsu
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Virgil L. Woods
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Darren E. Casteel
- Department of Medicine, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
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21
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Francis SH, Busch JL, Corbin JD, Sibley D. cGMP-dependent protein kinases and cGMP phosphodiesterases in nitric oxide and cGMP action. Pharmacol Rev 2010; 62:525-63. [PMID: 20716671 DOI: 10.1124/pr.110.002907] [Citation(s) in RCA: 695] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To date, studies suggest that biological signaling by nitric oxide (NO) is primarily mediated by cGMP, which is synthesized by NO-activated guanylyl cyclases and broken down by cyclic nucleotide phosphodiesterases (PDEs). Effects of cGMP occur through three main groups of cellular targets: cGMP-dependent protein kinases (PKGs), cGMP-gated cation channels, and PDEs. cGMP binding activates PKG, which phosphorylates serines and threonines on many cellular proteins, frequently resulting in changes in activity or function, subcellular localization, or regulatory features. The proteins that are so modified by PKG commonly regulate calcium homeostasis, calcium sensitivity of cellular proteins, platelet activation and adhesion, smooth muscle contraction, cardiac function, gene expression, feedback of the NO-signaling pathway, and other processes. Current therapies that have successfully targeted the NO-signaling pathway include nitrovasodilators (nitroglycerin), PDE5 inhibitors [sildenafil (Viagra and Revatio), vardenafil (Levitra), and tadalafil (Cialis and Adcirca)] for treatment of a number of vascular diseases including angina pectoris, erectile dysfunction, and pulmonary hypertension; the PDE3 inhibitors [cilostazol (Pletal) and milrinone (Primacor)] are used for treatment of intermittent claudication and acute heart failure, respectively. Potential for use of these medications in the treatment of other maladies continues to emerge.
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Affiliation(s)
- Sharron H Francis
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN 37232-0615, USA.
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22
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Functional osteoclast attachment requires inositol-1,4,5-trisphosphate receptor-associated cGMP-dependent kinase substrate. J Transl Med 2010; 90:1533-42. [PMID: 20567233 PMCID: PMC3114438 DOI: 10.1038/labinvest.2010.120] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Osteoclast activity is central to balanced bone turnover to maintain normal bone mass. A specialized osteoclast attachment to bone localizes acid secretion to remove bone mineral; in some cases, attachment is functionally impaired despite normal attachment proteins. The inositol-1,4,5-trisphosphate receptor-1 (IP3R1) is an intracellular calcium channel required for regulation of reversible osteoclast attachment by nitric oxide (NO), an important regulator of both normal and pathological bone degradation. In studies using human osteoclasts produced in vitro, we found that IP3R1 binds an endosomal isoform of the IP3R-associated cGMP-dependent kinase substrate (IRAG). IRAG is a substrate of cGMP-dependent kinase-1 (PKG1) and binds the PKG1 isoform PKG1β, which was the predominant form of PKG1 in human osteoclasts. Western blots of IRAG were consistent with NO-dependent serine phosphorylation of IRAG. An additional effect of PKG1β activity in osteoclasts was disassociation of IP3R1-IRAG complexes, as shown by analysis of IP3R1 complexes and by localization of the proteins within cells. IP3R1-IRAG complexes were stabilized by PKG or Src antagonists, Src activity being a requirement for IP3R1 calcium release downstream of PKG. IP3R1-mediated calcium release regulates cellular detachment in part through the calcium-dependent proteinase μ-calpain. In osteoclasts with IRAG suppressed by siRNA, activity of μ-calpain was increased relative to cells with normal IRAG, and regulation of μ-calpain by NO was lost. Furthermore, cells deficient in IRAG detached easily from substrate and had smaller attached diameters and randomly distributed podosomes, although IRAG knockdown did not affect cell viability. Our results indicate that IRAG is required for PKG1β-regulated cyclic calcium release during motility, and that disruption of the IP3R1-IRAG calcium regulation system is a novel cause of dysfunctional osteoclasts unrelated to defects in attachment proteins or acid secretion.
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Casteel DE, Smith-Nguyen EV, Sankaran B, Roh SH, Pilz RB, Kim C. A crystal structure of the cyclic GMP-dependent protein kinase I{beta} dimerization/docking domain reveals molecular details of isoform-specific anchoring. J Biol Chem 2010; 285:32684-32688. [PMID: 20826808 DOI: 10.1074/jbc.c110.161430] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cyclic GMP-dependent protein kinase (PKG) is a key mediator of the nitric oxide/cGMP signaling pathway and plays a central role in regulating cardiovascular and neuronal functions. The N-terminal ∼50 amino acids of the kinase are required for homodimerization and association with isoform-specific PKG-anchoring proteins (GKAPs), which target the kinase to specific substrates. To understand the molecular details of PKG dimerization and gain insight into its association with GKAPs, we solved a crystal structure of the PKG Iβ dimerization/docking domain. Our structure provides molecular details of this unique leucine/isoleucine zipper, revealing specific hydrophobic and ionic interactions that mediate dimerization and demonstrating the topology of the GKAP interaction surface.
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Affiliation(s)
- Darren E Casteel
- From the Department of Medicine and Cancer Center, San Diego, La Jolla, California 92093
| | - Eric V Smith-Nguyen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Sung H Roh
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030
| | - Renate B Pilz
- From the Department of Medicine and Cancer Center, San Diego, La Jolla, California 92093
| | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030.
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24
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Desch M, Sigl K, Hieke B, Salb K, Kees F, Bernhard D, Jochim A, Spiessberger B, Höcherl K, Feil R, Feil S, Lukowski R, Wegener JW, Hofmann F, Schlossmann J. IRAG determines nitric oxide- and atrial natriuretic peptide-mediated smooth muscle relaxation. Cardiovasc Res 2010; 86:496-505. [PMID: 20080989 DOI: 10.1093/cvr/cvq008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Nitric oxide (NO) and atrial natriuretic peptide (ANP) signalling via cGMP controls smooth muscle tone. One important signalling pathway of cGMP-dependent protein kinase type I (cGKI) is mediated by IRAG (IP(3) receptor associated cGKI substrate) which is highly expressed in smooth muscle tissues. To elucidate the role of IRAG for NO- and ANP-mediated smooth muscle tone regulation, cGKI localization, and for its possible function in blood pressure adjustment, we generated IRAG-knockout mice by targeted deletion of exon 3. METHODS AND RESULTS IRAG deletion prevented stable interaction of IP(3) receptor type I (IP(3)RI) with cGKIbeta determined by cGMP affinity chromatography. Confocal microscopy in vascular smooth muscle cells (VSMCs) showed that localization of cGKIbeta and cGKIalpha did not change in absence of IRAG. NO-, ANP-, and cGMP-dependent relaxation of hormone-contracted aortic vessels and colon was significantly affected in IRAG-knockout mice. The suppression of cGMP-induced relaxation was not rescued by selective expression of cGKIbeta in smooth muscle from cGKIbeta-transgenic mice. NO-, ANP-, and cGMP-mediated inhibition of the hormone-induced increase in intracellular calcium concentration measured by Fura2 was suppressed in IRAG-deficient VSMC. Telemetric measurements revealed that IRAG-deficient animals exhibited normal basal tone, but were resistant to blood pressure reduction induced by lipopolysaccharide-treatment. CONCLUSION These findings indicate that signalling of cGKIbeta via IRAG is an essential functional part for regulation of smooth muscle tone and of intracellular calcium by NO (exogenously applicated or endogenously synthesized) and by ANP. IRAG signalling does not modulate basal tone but might be important for blood pressure regulation under pathophysiological conditions.
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Affiliation(s)
- Matthias Desch
- Pharmakologie und Toxikologie, Universität Regensburg, Universitätstr. 31, D-93055 Regensburg, Germany
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25
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Abstract
Signalling of cGK (cGMP-dependent protein kinases) are mediated through phosphorylation of specific substrates. Several substrates of cGKI and cGKII were identified meanwhile. Some cGKI substrates are specifically regulated by the cGKIalpha or the cGKIbeta isozyme. In various cells and tissues, different cGK substrates exist that are essential for the regulation of diverse functions comprising tissue contractility, cell motility, cell contact, cellular secretion, cell proliferation, and cell differentiation. On the molecular level, cGKI substrates fulfill various cellular functions regulating e.g. the intracellular calcium and potassium concentration, the calcium sensitivity, and the organisation of the intracellular cytoskeleton. cGKII substrates are involved e.g. in chloride transport, sodium/proton transport and transcriptional regulation. The understanding of cGK signalling and function depends strongly on the identification of further specific substrates. In the last years, diverse approaches ranging from biochemistry to genetic deletion lead to the identification and establishment of several substrates, which raised new insights in the molecular mechanisms of cGK functions and elucidated new cellular cGK functions. However, the analysis of the dynamic signalling of cGK in tissues and cells will be necessary to discover new signalling pathways and substrates.
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Affiliation(s)
- Jens Schlossmann
- Institut für Pharmakologie und Toxikologie, Universität Regensburg, Regensburg, 93055, Germany.
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26
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Graham SM, Longoria S, Sarkar P, Koulen P. Inositol 1,4,5-triphosphate-associated cGMP kinase substrate: Basis Sequence: Mouse. ACTA ACUST UNITED AC 2008; 2008. [PMID: 26023301 DOI: 10.1038/mp.a001275.01] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Inositol 1, 4, 5-trisphosphate (IP3) receptor associated cyclic GMP (cGMP) kinase substrate (IRAG, also known as Mrv1) is a type-2 integral membrane endoplasmic reticulum (ER) protein, which interacts with IP3 Receptor type 1 (IP3R1), cGMP kinase I-β (cGKI β) and other associated proteins. It plays a key role in NO, cGMP, and cGKI β mediated inhibition of IP3R1 activity and thus relaxes smooth muscle tone and inhibits platelet aggregation. As a scaffolding protein Mrv1 maintains the conformation of a heteroprotein complex containing cGKI β, IP3R1 and other proteins and enables efficient activity of cGKI β within the complex. Increased expression of Mrv1 or IRAG in the absence of tumor related transcription factor in pancreatic cancer cells suggest that it might be involved in tumorigenesis. Downregulation of Mrv1 during megakaryocyte maturation indicates that it is involved in cell growth and differentiation.
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Affiliation(s)
| | - Sandra Longoria
- Pharmacology and Neuroscience, Univerisity of North Texas Health Science Center, TX 76116, US
| | - Pabak Sarkar
- Molecular Biology and Immunology, University Of North Texas Health Science Center, TX 76107, US
| | - Peter Koulen
- Departments of Ophthalmology and Basic Medical Sciences, University of Missouri - Kansas City, School of Medicine, MO 64108, US
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27
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Casteel DE, Zhang T, Zhuang S, Pilz RB. cGMP-dependent protein kinase anchoring by IRAG regulates its nuclear translocation and transcriptional activity. Cell Signal 2008; 20:1392-9. [PMID: 18450420 DOI: 10.1016/j.cellsig.2008.03.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 03/14/2008] [Accepted: 03/17/2008] [Indexed: 10/24/2022]
Abstract
Type I cGMP-dependent protein kinases (PKGs) translocate to the nucleus to regulate gene expression in some, but not all cell types; we hypothesized that nuclear translocation of PKG may be regulated by extra-nuclear anchoring proteins. The inositol 1,4,5-triphosphate (IP(3)) receptor-associated cGMP kinase substrate (IRAG) binds to the N-terminus of PKG Ibeta, but not PKG Ialpha, and in smooth muscle cells, IRAG and PKG Ibeta are in a complex with the IP(3) receptor at endoplasmatic reticulum membranes, where the complex regulates calcium release [Schlossmann et al., Nature, 404 (2000) 197]. We found that co-expression of IRAG and PKG Ibeta in baby hamster kidney cells prevented cGMP-induced PKG Ibeta translocation to the nucleus, and decreased cGMP/PKG Ibeta transactivation of a cAMP-response element-dependent reporter gene. These effects required the PKG Ibeta/IRAG association, as demonstrated by a binding-incompetent IRAG mutant, and were specific for PKG Ibeta, as nuclear translocation and reporter gene activation by PKG Ialpha was not affected by IRAG. A phosphorylation-deficient IRAG mutant that is no longer functionally regulated by PKG phosphorylation suppressed cGMP/PKG Ibeta transcriptional activity, indicating that IRAG's effect was not explained by changes in intracellular calcium, and was not related to competition of IRAG with other PKG substrates. These results demonstrate that PKG anchoring to a specific binding protein is sufficient to dictate subcellular localization of the kinase and affect cGMP signaling in the nucleus, and may explain why nuclear translocation of PKG I does not occur in all cell types.
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Affiliation(s)
- Darren E Casteel
- Department of Medicine and Cancer Center, University of California at San Diego, La Jolla, CA 92093-0652, United States
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Roberts JD, Chiche JD, Kolpa EM, Bloch DB, Bloch KD. cGMP-dependent protein kinase I interacts with TRIM39R, a novel Rpp21 domain-containing TRIM protein. Am J Physiol Lung Cell Mol Physiol 2007; 293:L903-12. [PMID: 17601797 DOI: 10.1152/ajplung.00157.2007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide modulates vascular smooth muscle cell (SMC) cytoskeletal kinetics and phenotype, in part, by stimulating cGMP-dependent protein kinase I (PKGI). To identify molecular targets of PKGI, an interaction trap screen in yeast was performed using a cDNA encoding the catalytic region of PKGI and a human lung cDNA library. We identified a cDNA that encodes a putative PKGI-interactor that is a novel variant of TRIM39, a member of the really interesting new gene (RING) finger family of proteins. Although this TRIM39 variant encodes the NH2-terminal RING finger (RF), B-box, and coiled-coil (RBBC) domains of TRIM39, instead of a complete COOH-terminal B30.2 domain, this TRIM39 isoform contains the COOH-terminal portion of Rpp21, a component of RNase P. RT-PCR demonstrated that the TRIM39 variant, which we refer to as TRIM39R, is transcribed in the human fetal lung and in rat pulmonary artery SMC. Indirect immunofluorescence using an antibody generated against the conserved domains of TRIM39 and TRIM39R revealed the proteins in speckled intranuclear structures in human acute monocytic leukemia (THP-1) and human epidermal carcinoma line (HEp-2) cells. PKGI phosphorylated a typical PKGI/PKA phosphorylation domain in a conserved region of TRIM39 and TRIM39R. Additional studies demonstrated that PKGI interacts with both isoforms of TRIM39 in yeast cells and phosphorylates both isoforms of TRIM39 in human cell lines. Although PKGI has been observed to interact with proteins that regulate cytoskeletal function and gene expression, this investigation shows for the first time that PKGI interacts with tripartite motif (TRIM) proteins, which, through diverse molecular pathways, are often observed to regulate important aspects of cellular homeostasis.
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Given AM, Ogut O, Brozovich FV. MYPT1 mutants demonstrate the importance of aa 888–928 for the interaction with PKGIα. Am J Physiol Cell Physiol 2007; 292:C432-9. [PMID: 16870832 DOI: 10.1152/ajpcell.00175.2006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During nitric oxide signaling, type Iα cGMP-dependent protein kinase (PKGIα) activates myosin light chain (MLC) phosphatase through an interaction with the 130-kDa myosin targeting subunit (MYPT1), leading to dephosphorylation of 20-kDa MLC and vasodilatation. It has been suggested that the MYPT1-PKGIα interaction is mediated by the COOH-terminal leucine zipper (LZ) of MYPT1 and the NH2-terminal LZ of PKGIα (HK Surks and ME Mendelsohn. Cell Signal 15: 937–944, 2003; HK Surks et al. Science 286: 1583–1587, 1999), but we previously showed that PKGIα interacts with LZ-positive (LZ+) and LZ-negative (LZ−) MYPT1 isoforms ( 13 ). Interestingly, PKGIα is known to preferentially bind to RR and RK motifs (WR Dostmann et al. Proc Natl Acad Sci USA 97: 14772–14777, 2000), and there is an RK motif within the aa 888–928 sequence of MYPT1 in LZ+ and LZ− isoforms. Thus, to localize the domain of MYPT1 important for the MYPT1-PKGIα interaction, we designed four MYPT1 fragments that contained both the aa 888–928 sequence and the downstream LZ domain (MYPT1FL), lacked both the aa 888–928 sequence and the LZ domain (MYPT1TR), lacked only the aa 888–928 sequence (MYPT1SO), or lacked only the LZ domain (MYPT1TR2). Using coimmunoprecipitation, we found that only the fragments containing the aa 888–928 sequence (MYPT1FL and MYPT1TR2) were able to form a complex with PKGIα in avian smooth muscle tissue lysates. Furthermore, mutations of the RK motif at aa 916–917 (R916K917) to AA decreased binding of MYPT1 to PKGIα in chicken gizzard lysates; these mutations had no effect on binding in chicken aorta lysates. However, mutation of R916K917to E916E917eliminated binding, suggesting that one factor important for the PKGIα-MYPT1 interaction is the charge at aa 916–917. These results suggest that, during cGMP-mediated signaling, aa 888–928 of MYPT1 mediate the PKGIα-MYPT1 interaction.
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Affiliation(s)
- Allison M Given
- Division of Cardiovascular Diseases, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
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