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Kalyanaraman H, Casteel DE, China SP, Zhuang S, Boss GR, Pilz RB. A plasma membrane-associated form of the androgen receptor enhances nuclear androgen signaling in osteoblasts and prostate cancer cells. Sci Signal 2024; 17:eadi7861. [PMID: 38289986 PMCID: PMC10916501 DOI: 10.1126/scisignal.adi7861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 01/09/2024] [Indexed: 02/01/2024]
Abstract
Androgen binding to the androgen receptor (AR) in the cytoplasm induces the AR to translocate to the nucleus, where it regulates the expression of target genes. Here, we found that androgens rapidly activated a plasma membrane-associated signaling node that enhanced nuclear AR functions. In murine primary osteoblasts, dihydrotestosterone (DHT) binding to a membrane-associated form of AR stimulated plasma membrane-associated protein kinase G type 2 (PKG2), leading to the activation of multiple kinases, including ERK. Phosphorylation of AR at Ser515 by ERK increased the nuclear accumulation and binding of AR to the promoter of Ctnnb1, which encodes the transcription factor β-catenin. In male mouse osteoblasts and human prostate cancer cells, DHT induced the expression of Ctnnb1 and CTNN1B, respectively, as well as β-catenin target genes, stimulating the proliferation, survival, and differentiation of osteoblasts and the proliferation of prostate cancer cells in a PKG2-dependent fashion. Because β-catenin is a master regulator of skeletal homeostasis, these results explain the reported male-specific osteoporotic phenotype of mice lacking PKG2 in osteoblasts and imply that PKG2-dependent AR signaling is essential for maintaining bone mass in vivo. Our results suggest that widely used pharmacological PKG activators, such as sildenafil, could be beneficial for male and estrogen-deficient female patients with osteoporosis but detrimental in patients with prostate cancer.
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Darren E. Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shyamsundar Pal China
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shunhui Zhuang
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gerry R. Boss
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Renate B. Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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2
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Kalyanaraman H, Casteel DE, Cabriales JA, Tat J, Zhuang S, Chan A, Dretchen KL, Boss GR, Pilz RB. The Antioxidant/Nitric Oxide-Quenching Agent Cobinamide Prevents Aortic Disease in a Mouse Model of Marfan Syndrome. JACC Basic Transl Sci 2024; 9:46-62. [PMID: 38362350 PMCID: PMC10864892 DOI: 10.1016/j.jacbts.2023.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/18/2023] [Accepted: 07/24/2023] [Indexed: 02/17/2024]
Abstract
Major pathologic changes in the proximal aorta underlie the life-threatening aortic aneurysms and dissections in Marfan Syndrome; current treatments delay aneurysm development without addressing the primary pathology. Because excess oxidative stress and nitric oxide/protein kinase G signaling likely contribute to the aortopathy, we hypothesized that cobinamide, a strong antioxidant that can attenuate nitric oxide signaling, could be uniquely suited to prevent aortic disease. In a well-characterized mouse model of Marfan Syndrome, cobinamide dramatically reduced elastin breaks, prevented excess collagen deposition and smooth muscle cell apoptosis, and blocked DNA, lipid, and protein oxidation and excess nitric oxide/protein kinase G signaling in the ascending aorta. Consistent with preventing pathologic changes, cobinamide diminished aortic root dilation without affecting blood pressure. Cobinamide exhibited excellent safety and pharmacokinetic profiles indicating it could be a practical treatment. We conclude that cobinamide deserves further study as a disease-modifying treatment of Marfan Syndrome.
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | - Darren E. Casteel
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | - Justin A. Cabriales
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | - John Tat
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | - Shunhui Zhuang
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | - Adriano Chan
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | | | - Gerry R. Boss
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
| | - Renate B. Pilz
- Department of Medicine, University of California-San Diego, La Jolla, California, USA
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3
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Hu T, Kalyanaraman H, Pilz RB, Casteel DE. Phosphatase regulatory subunit MYPT2 knock-out partially compensates for the cardiac dysfunction in mice caused by lack of myosin light chain kinase 3. J Biol Chem 2023; 299:104584. [PMID: 36889588 PMCID: PMC10124902 DOI: 10.1016/j.jbc.2023.104584] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023] Open
Abstract
Cardiac contraction is modulated by the phosphorylation state of myosin regulatory light chain 2 (MLC-2v). The level of MLC-2v phosphorylation is dependent on the opposing activities of MLC kinases and phosphatases. The predominant MLC phosphatase found in cardiac myocytes contains Myosin Phosphatase Targeting Subunit 2 (MYPT2). Overexpression of MYPT2 in cardiac myocytes results in a decreased level of MLC phosphorylation, reduced left ventricular contraction and induction of hypertrophy; however, the effect of knocking out MYPT2 on cardiac function is unknown. We obtained heterozygous mice containing a MYPT2 null allele from the Mutant Mouse Resource Center. These mice were produced in a C57BL/6N background which lack MLCK3, the main regulatory light chain kinase in cardiac myocytes. We found that mice null for MYPT2 were viable and had no obvious phenotypic abnormality when compared to wild-type mice. Additionally, we determined that wild-type C57BL/6N mice had a low basal level of MLC-2v phosphorylation which was significantly increased when MYPT2 was absent. At 12-weeks, MYPT2 knock-out mice had smaller hearts and showed down-regulation of genes involved in cardiac remodeling. Using cardiac echo, we found that 24-week-old male MYPT2 knock-out mice had decreased heart size with increased fractional shortening compared to their MYPT2 wild-type littermates. Collectively, these studies highlight the important role that MYPT2 plays in cardiac function in vivo and demonstrate that its deletion can partially compensate for the lack of MLCK3.
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Affiliation(s)
- Tingfei Hu
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093.
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4
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Kalyanaraman H, China SP, Cabriales JA, Moininazeri J, Casteel DE, Garcia JJ, Wong VW, Chen A, Sah RL, Boss GR, Pilz RB. Protein Kinase G2 Is Essential for Skeletal Homeostasis and Adaptation to Mechanical Loading in Male but Not Female Mice. J Bone Miner Res 2023; 38:171-185. [PMID: 36371651 PMCID: PMC9825661 DOI: 10.1002/jbmr.4746] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 11/04/2022] [Accepted: 11/10/2022] [Indexed: 11/14/2022]
Abstract
We previously showed that the NO/cGMP/protein kinase G (PKG) signaling pathway positively regulates osteoblast proliferation, differentiation, and survival in vitro, and that cGMP-elevating agents have bone-anabolic effects in mice. Here, we generated mice with an osteoblast-specific (OB) knockout (KO) of type 2 PKG (gene name Prkg2) using a Col1a1(2.3 kb)-Cre driver. Compared to wild type (WT) littermates, 8-week-old male OB Prkg2-KO mice had fewer osteoblasts, reduced bone formation rates, and lower trabecular and cortical bone volumes. Female OB Prkg2-KO littermates showed no bone abnormalities, despite the same degree of PKG2 deficiency in bone. Expression of osteoblast differentiation- and Wnt/β-catenin-related genes was lower in primary osteoblasts and bones of male KO but not female KO mice compared to WT littermates. Osteoclast parameters were unaffected in both sexes. Since PKG2 is part of a mechano-sensitive complex in osteoblast membranes, we examined its role during mechanical loading. Cyclical compression of the tibia increased cortical thickness and induced mechanosensitive and Wnt/β-catenin-related genes to a similar extent in male and female WT mice and female OB Prkg2-KO mice, but loading had a minimal effect in male KO mice. We conclude that PKG2 drives bone acquisition and adaptation to mechanical loading via the Wnt/β-catenin pathway in male mice. The striking sexual dimorphism of OB Prkg2-KO mice suggests that current U.S. Food and Drug Administration-approved cGMP-elevating agents may represent novel effective treatment options for male osteoporosis. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- These two authors contributed equally to the work
| | - Shyamsundar Pal China
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- These two authors contributed equally to the work
| | - Justin A. Cabriales
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jafar Moininazeri
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Darren E. Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Julian J. Garcia
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Van W. Wong
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Albert Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Robert L. Sah
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gerry R. Boss
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Renate B. Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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5
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Chang S, Tat J, China SP, Kalyanaraman H, Zhuang S, Chan A, Lai C, Radic Z, Abdel-Rahman EA, Casteel DE, Pilz RB, Ali SS, Boss GR. Cobinamide is a strong and versatile antioxidant that overcomes oxidative stress in cells, flies, and diabetic mice. PNAS Nexus 2022; 1:pgac191. [PMID: 36276587 PMCID: PMC9578022 DOI: 10.1093/pnasnexus/pgac191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/12/2022] [Indexed: 01/29/2023]
Abstract
Increased oxidative stress underlies a variety of diseases, including diabetes. Here, we show that the cobalamin/vitamin B12 analog cobinamide is a strong and multifaceted antioxidant, neutralizing superoxide, hydrogen peroxide, and peroxynitrite, with apparent rate constants of 1.9 × 108, 3.7 × 104, and 6.3 × 106 M-1 s-1, respectively, for cobinamide with the cobalt in the +2 oxidation state. Cobinamide with the cobalt in the +3 oxidation state yielded apparent rate constants of 1.1 × 108 and 8.0 × 102 M-1 s-1 for superoxide and hydrogen peroxide, respectively. In mammalian cells and Drosophila melanogaster, cobinamide outperformed cobalamin and two well-known antioxidants, imisopasem manganese and manganese(III)tetrakis(4-benzoic acid)porphyrin, in reducing oxidative stress as evidenced by: (i) decreased mitochondrial superoxide and return of the mitochondrial membrane potential in rotenone- and antimycin A-exposed H9c2 rat cardiomyocytes; (ii) reduced JNK phosphorylation in hydrogen-peroxide-treated H9c2 cells; (iii) increased growth in paraquat-exposed COS-7 fibroblasts; and (iv) improved survival in paraquat-treated flies. In diabetic mice, cobinamide administered in the animals' drinking water completely prevented an increase in lipid and protein oxidation, DNA damage, and fibrosis in the heart. Cobinamide is a promising new antioxidant that has potential use in diseases with heightened oxidative stress.
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Affiliation(s)
| | | | | | | | - Shunhui Zhuang
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Adriano Chan
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cassandra Lai
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zoran Radic
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Engy A Abdel-Rahman
- Tumor Biology Research Program, Children’s Cancer Hospital, Cairo 57357, Egypt,Pharmacology Department, Faculty of Medicine, Assuit University, Assuit 71515, Egypt
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Aminzai S, Hu T, Pilz RB, Casteel DE. PKGIα is activated by metal-dependent oxidation in vitro but not in intact cells. J Biol Chem 2022; 298:102175. [PMID: 35752367 PMCID: PMC9293632 DOI: 10.1016/j.jbc.2022.102175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 11/02/2022] Open
Abstract
Type I cGMP-dependent protein kinases (PKGIs) are important components of various signaling pathways, and are canonically activated by nitric oxide- and natriuretic peptide-induced cGMP generation. However, some reports have shown that PKGIα can also be activated in vitro by oxidizing agents. Using in vitro kinase assays, here we found that purified PKGIα stored in phosphate-buffered saline with Flag peptide became oxidized and activated even in the absence of oxidizing agent; furthermore, once established, this activation could not be reversed by reduction with dithiothreitol. We demonstrate that activation was enhanced by addition of Cu2+ before storage, indicating it was driven by oxidation and mediated by trace metals present during storage. Previous reports suggested that PKGIα Cys43, Cys118, and Cys196 play key roles in oxidation-induced kinase activation; we show that activation was reduced by C118A or C196V mutations, although C43S PKGIα activation was not reduced. In contrast, under the same conditions, purified PKGIβ activity only slightly increased with storage. Using PKGIα/PKGIβ chimeras, we found that residues throughout the PKGIα-specific autoinhibitory loop were responsible for this activation. To explore whether oxidants activate PKGIα in H9c2 and C2C12 cells, we monitored vasodilator-stimulated phosphoprotein (VASP) phosphorylation downstream of PKGIα. While we observed PKGIα Cys43 crosslinking in response to H2O2 (indicating an oxidizing environment in the cells), we were unable to detect increased VASP phosphorylation under these conditions. Taken together, we conclude that while PKGIα can be readily activated by oxidation in vitro, there is currently no direct evidence of oxidation-induced PKGIα activation in vivo.
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Affiliation(s)
- Sahar Aminzai
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Tingfei Hu
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093.
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Schwaerzer GK, Casteel DE, Cividini F, Kalyanaraman H, Zhuang S, Gu Y, Peterson KL, Dillmann W, Boss GR, Pilz RB, Pilz RB. Constitutive protein kinase G activation exacerbates stress-induced cardiomyopathy. Br J Pharmacol 2022; 179:2413-2429. [PMID: 34000062 PMCID: PMC9926932 DOI: 10.1111/bph.15530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Heart failure is associated with high morbidity and mortality, and new therapeutic targets are needed. Preclinical data suggest that pharmacological activation of protein kinase G (PKG) can reduce maladaptive ventricular remodelling and cardiac dysfunction in the stressed heart. However, clinical trial results have been mixed and the effects of long-term PKG activation in the heart are unknown. EXPERIMENTAL APPROACH We characterized the cardiac phenotype of mice carrying a heterozygous knock-in mutation of PKG1 (Prkg1R177Q/+ ), which causes constitutive, cGMP-independent activation of the kinase. We examined isolated cardiac myocytes and intact mice, the latter after stress induced by surgical transaortic constriction or angiotensin II (Ang II) infusion. KEY RESULTS Cardiac myocytes from Prkg1R177Q/+ mice showed altered phosphorylation of sarcomeric proteins and reduced contractility in response to electrical stimulation, compared to cells from wild type mice. Under basal conditions, young PKG1R177Q/+ mice exhibited no obvious cardiac abnormalities, but aging animals developed mild increases in cardiac fibrosis. In response to angiotensin II infusion or fixed pressure overload induced by transaortic constriction, young PKGR177Q/+ mice exhibited excessive hypertrophic remodelling with increased fibrosis and myocyte apoptosis, leading to increased left ventricular dilation and dysfunction compared to wild type litter mates. CONCLUSION AND IMPLICATIONS Long-term PKG1 activation in mice may be harmful to the heart, especially in the presence of pressure overload and neurohumoral stress. LINKED ARTICLES This article is part of a themed issue on cGMP Signalling in Cell Growth and Survival. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.11/issuetoc.
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Affiliation(s)
- Gerburg K. Schwaerzer
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Darren E. Casteel
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Federico Cividini
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Hema Kalyanaraman
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Shunhui Zhuang
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Kirk L. Peterson
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Wolfgang Dillmann
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Gerry R. Boss
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Renate B. Pilz
- Department of Medicine, University of California San Diego, La Jolla, California 92093,Correspondence should be addressed to R.B.P. ()
| | - Renate B Pilz
- Department of Medicine, University of California San Diego, La Jolla, California, 92093, USA
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9
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Sahu D, Huan J, Wang H, Sahoo D, Casteel DE, Klemke RL, Boss GR, Hansel DE. Bladder Cancer Invasion Is Mediated by Mammalian Target of Rapamycin Complex 2-Driven Regulation of Nitric Oxide and Invadopodia Formation. Am J Pathol 2021; 191:2203-2218. [PMID: 34428425 DOI: 10.1016/j.ajpath.2021.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/14/2021] [Accepted: 08/06/2021] [Indexed: 01/05/2023]
Abstract
Bladder cancer invasion depends on mammalian target of rapamycin complex 2 (mTORC2) activity, although the downstream mTORC2 effectors that mediate this effect have not been fully defined. One potential downstream effector is the arginine derivative nitric oxide (NO). We identified a stage-associated increase in the expression of the NO-generating enzymes endothelial NO synthase (NOS) and inducible NOS (iNOS) in human bladder cancer. Reduction of NOS activity by pharmacologic inhibition or silencing of NOS enzymes reduced cancer cell invasion, with similar effects observed using the NO scavenger cobinamide. By contrast, enhanced invasion was seen with the NO donor Deta-NONOate and an analog of the downstream NO second messenger cGMP. We next evaluated NOS expression in invadopodia, which are cellular protrusions that form the invasive tips of cancer cells. Invadopodia were enriched in both iNOS protein and mTORC2 activity, and invadopodia formation was increased by Deta-NONOate and decreased by cobinamide and ablation of mTORC2 activity. mTORC2 additionally increased expression of iNOS. Using a zebrafish model, injection of iNOS- or rictor-silenced cells reduced the frequency of bladder cancer cell metastasis in zebrafish. These results indicate that mTORC2 can mediate bladder cancer cell invasion through increased iNOS expression, resulting in increased NO and cGMP production in invadopodia and further propagation of invadopodia formation.
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Affiliation(s)
- Divya Sahu
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Jianya Huan
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, Oregon
| | - Huawei Wang
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Debashis Sahoo
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Darren E Casteel
- Department of Medicine, University of California at San Diego, La Jolla, California
| | - Richard L Klemke
- Department of Pathology & Laboratory Medicine, University of California at San Diego, La Jolla, California
| | - Gerry R Boss
- Department of Medicine, University of California at San Diego, La Jolla, California
| | - Donna E Hansel
- Department of Pathology & Laboratory Medicine, Oregon Health & Science University, Portland, Oregon.
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10
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Cividini F, Scott BT, Suarez J, Casteel DE, Heinz S, Dai A, Diemer T, Suarez JA, Benner CW, Ghassemian M, Dillmann WH. Ncor2/PPARα-Dependent Upregulation of MCUb in the Type 2 Diabetic Heart Impacts Cardiac Metabolic Flexibility and Function. Diabetes 2021; 70:665-679. [PMID: 33303689 PMCID: PMC7897348 DOI: 10.2337/db20-0779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/27/2020] [Indexed: 12/14/2022]
Abstract
The contribution of altered mitochondrial Ca2+ handling to metabolic and functional defects in type 2 diabetic (T2D) mouse hearts is not well understood. In this study, we show that the T2D heart is metabolically inflexible and almost exclusively dependent on mitochondrial fatty acid oxidation as a consequence of mitochondrial calcium uniporter complex (MCUC) inhibitory subunit MCUb overexpression. Using a recombinant endonuclease-deficient Cas9-based gene promoter pulldown approach coupled with mass spectrometry, we found that MCUb is upregulated in the T2D heart due to loss of glucose homeostasis regulator nuclear receptor corepressor 2 repression, and chromatin immunoprecipitation assays identified peroxisome proliferator-activated receptor α as a mediator of MCUb gene expression in T2D cardiomyocytes. Upregulation of MCUb limits mitochondrial matrix Ca2+ uptake and impairs mitochondrial energy production via glucose oxidation by depressing pyruvate dehydrogenase complex activity. Gene therapy displacement of endogenous MCUb with a dominant-negative MCUb transgene (MCUbW246R/V251E) in vivo rescued T2D cardiomyocytes from metabolic inflexibility and stimulated cardiac contractile function and adrenergic responsiveness by enhancing phospholamban phosphorylation via protein kinase A. We conclude that MCUb represents one newly discovered molecular effector at the interface of metabolism and cardiac function, and its repression improves the outcome of the chronically stressed diabetic heart.
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Affiliation(s)
- Federico Cividini
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Brian T Scott
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Jorge Suarez
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Sven Heinz
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Anzhi Dai
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Tanja Diemer
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Jorge A Suarez
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | | | - Majid Ghassemian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA
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11
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Wahwah N, Dhar D, Chen H, Zhuang S, Chan A, Casteel DE, Kalyanaraman H, Pilz RB, Boss GR. Metabolic interaction between amino acid deprivation and cisplatin synergistically reduces phosphoribosyl-pyrophosphate and augments cisplatin cytotoxicity. Sci Rep 2020; 10:19907. [PMID: 33199755 PMCID: PMC7670436 DOI: 10.1038/s41598-020-76958-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/04/2020] [Indexed: 11/09/2022] Open
Abstract
Cisplatin is a mainstay of cancer chemotherapy. It forms DNA adducts, thereby activating poly(ADP-ribose) polymerases (PARPs) to initiate DNA repair. The PARP substrate NAD+ is synthesized from 5-phosphoribose-1-pyrophosphate (PRPP), and we found that treating cells for 6 h with cisplatin reduced intracellular PRPP availability. The decrease in PRPP was likely from (1) increased PRPP consumption, because cisplatin increased protein PARylation and PARP1 shRNA knock-down returned PRPP towards normal, and (2) decreased intracellular phosphate, which down-regulated PRPP synthetase activity. Depriving cells of a single essential amino acid decreased PRPP synthetase activity with a half-life of ~ 8 h, and combining cisplatin and amino acid deprivation synergistically reduced intracellular PRPP. PRPP is a rate-limiting substrate for purine nucleotide synthesis, and cisplatin inhibited de novo purine synthesis and DNA synthesis, with amino acid deprivation augmenting cisplatin’s effects. Amino acid deprivation enhanced cisplatin’s cytotoxicity, increasing cellular apoptosis and DNA strand breaks in vitro, and intermittent deprivation of lysine combined with a sub-therapeutic dose of cisplatin inhibited growth of ectopic hepatomas in mice. Augmentation of cisplatin’s biochemical and cytotoxic effects by amino acid deprivation suggest that intermittent deprivation of an essential amino acid could allow dose reduction of cisplatin; this could reduce the drug’s side effects, and allow its use in cisplatin-resistant tumors.
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Affiliation(s)
- Nisreen Wahwah
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Debanjan Dhar
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Hui Chen
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Shunhui Zhuang
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Adriano Chan
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA
| | - Gerry R Boss
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093-0652, USA.
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12
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Chan MH, Aminzai S, Hu T, Taran A, Li S, Kim C, Pilz RB, Casteel DE. A substitution in cGMP-dependent protein kinase 1 associated with aortic disease induces an active conformation in the absence of cGMP. J Biol Chem 2020; 295:10394-10405. [PMID: 32506052 DOI: 10.1074/jbc.ra119.010984] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 06/04/2020] [Indexed: 01/27/2023] Open
Abstract
Type 1 cGMP-dependent protein kinases (PKGs) play important roles in human cardiovascular physiology, regulating vascular tone and smooth-muscle cell phenotype. A mutation in the human PRKG1 gene encoding cGMP-dependent protein kinase 1 (PKG1) leads to thoracic aortic aneurysms and dissections. The mutation causes an arginine-to-glutamine (RQ) substitution within the first cGMP-binding pocket in PKG1. This substitution disrupts cGMP binding to the pocket, but it also unexpectedly causes PKG1 to have high activity in the absence of cGMP via an unknown mechanism. Here, we identified the molecular mechanism whereby the RQ mutation increases basal kinase activity in the human PKG1α and PKG1β isoforms. Although we found that the RQ substitution (R177Q in PKG1α and R192Q in PKG1β) increases PKG1α and PKG1β autophosphorylation in vitro, we did not detect increased autophosphorylation of the PKG1α or PKG1β RQ variant isolated from transiently transfected 293T cells, indicating that increased basal activity of the RQ variants in cells was not driven by PKG1 autophosphorylation. Replacement of Arg-177 in PKG1α with alanine or methionine also increased basal activity. PKG1 exists as a parallel homodimer linked by an N-terminal leucine zipper, and we show that the WT chain in WT-RQ heterodimers partly reduces basal activity of the RQ chain. Using hydrogen/deuterium-exchange MS, we found that the RQ substitution causes PKG1β to adopt an active conformation in the absence of cGMP, similar to that of cGMP-bound WT enzyme. We conclude that the RQ substitution in PKG1 increases its basal activity by disrupting the formation of an inactive conformation.
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Affiliation(s)
- Matthew H Chan
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Sahar Aminzai
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Tingfei Hu
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Amatya Taran
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Sheng Li
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Choel Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology and the Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
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13
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Affiliation(s)
- Choel Kim
- Baylor College of Medicine, Pharmacology and Chemical Biology, Houston, TX, USA. .,Baylor College of Medicine, Biochemistry and Molecular Biology, Houston, TX, USA.
| | - Rajesh Sharma
- Baylor College of Medicine, Pharmacology and Chemical Biology, Houston, TX, USA
| | - Darren E Casteel
- University of California, San Diego, Medicine, La Jolla, CA, USA
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14
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Casteel DE. Letter by Casteel Regarding Article, "Blood Pressure-Lowering by the Antioxidant Resveratrol Is Counterintuitively Mediated by Oxidation of the cGMP-Dependent Protein Kinase". Circulation 2019; 140:e808-e809. [PMID: 31765253 DOI: 10.1161/circulationaha.119.042120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Schwaerzer GK, Kalyanaraman H, Casteel DE, Dalton ND, Gu Y, Lee S, Zhuang S, Wahwah N, Schilling JM, Patel HH, Zhang Q, Makino A, Milewicz DM, Peterson KL, Boss GR, Pilz RB. Aortic pathology from protein kinase G activation is prevented by an antioxidant vitamin B 12 analog. Nat Commun 2019; 10:3533. [PMID: 31387997 PMCID: PMC6684604 DOI: 10.1038/s41467-019-11389-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 07/11/2019] [Indexed: 01/08/2023] Open
Abstract
People heterozygous for an activating mutation in protein kinase G1 (PRKG1, p.Arg177Gln) develop thoracic aortic aneurysms and dissections (TAAD) as young adults. Here we report that mice heterozygous for the mutation have a three-fold increase in basal protein kinase G (PKG) activity, and develop age-dependent aortic dilation. Prkg1R177Q/+ aortas show increased smooth muscle cell apoptosis, elastin fiber breaks, and oxidative stress compared to aortas from wild type littermates. Transverse aortic constriction (TAC)—to increase wall stress in the ascending aorta—induces severe aortic pathology and mortality from aortic rupture in young mutant mice. The free radical-neutralizing vitamin B12-analog cobinamide completely prevents age-related aortic wall degeneration, and the unrelated anti-oxidant N-acetylcysteine ameliorates TAC-induced pathology. Thus, increased basal PKG activity induces oxidative stress in the aorta, raising concern about the widespread clinical use of PKG-activating drugs. Cobinamide could be a treatment for aortic aneurysms where oxidative stress contributes to the disease, including Marfan syndrome. Individuals carrying a gain-of-function mutation in PKG1 develop thoracic aortic aneurysms and dissections. Here Schwaerzer et al. show that mice carrying the same mutation recapitulate the human disease, and find that treatment with anti-oxidants including cobinamide, a vitamin B12 analog, prevents disease progression.
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Affiliation(s)
- Gerburg K Schwaerzer
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Hema Kalyanaraman
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Darren E Casteel
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nancy D Dalton
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Seunghoe Lee
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Shunhui Zhuang
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nisreen Wahwah
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Jan M Schilling
- Department of Anesthesiology, University of California San Diego, La Jolla, CA, 92093, USA
| | - Hemal H Patel
- Department of Anesthesiology, University of California San Diego, La Jolla, CA, 92093, USA
| | - Qian Zhang
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Ayako Makino
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Dianna M Milewicz
- Division of Medical Genetics and Cardiology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Kirk L Peterson
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Gerry R Boss
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Renate B Pilz
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA.
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16
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Ramdani G, Schall N, Kalyanaraman H, Wahwah N, Moheize S, Lee JJ, Sah RL, Pfeifer A, Casteel DE, Pilz RB. cGMP-dependent protein kinase-2 regulates bone mass and prevents diabetic bone loss. J Endocrinol 2018; 238:203-219. [PMID: 29914933 PMCID: PMC6086127 DOI: 10.1530/joe-18-0286] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 06/18/2018] [Indexed: 11/08/2022]
Abstract
NO/cGMP signaling is important for bone remodeling in response to mechanical and hormonal stimuli, but the downstream mediator(s) regulating skeletal homeostasis are incompletely defined. We generated transgenic mice expressing a partly-activated, mutant cGMP-dependent protein kinase type 2 (PKG2R242Q) under control of the osteoblast-specific Col1a1 promoter to characterize the role of PKG2 in post-natal bone formation. Primary osteoblasts from these mice showed a two- to three-fold increase in basal and total PKG2 activity; they proliferated faster and were resistant to apoptosis compared to cells from WT mice. Male Col1a1-Prkg2R242Q transgenic mice had increased osteoblast numbers, bone formation rates and Wnt/β-catenin-related gene expression in bone and a higher trabecular bone mass compared to their WT littermates. Streptozotocin-induced type 1 diabetes suppressed bone formation and caused rapid bone loss in WT mice, but male transgenic mice were protected from these effects. Surprisingly, we found no significant difference in bone micro-architecture or Wnt/β-catenin-related gene expression between female WT and transgenic mice; female mice of both genotypes showed higher systemic and osteoblastic NO/cGMP generation compared to their male counterparts, and a higher level of endogenous PKG2 activity may be responsible for masking effects of the PKG2R242Q transgene in females. Our data support sexual dimorphism in Wnt/β-catenin signaling and PKG2 regulation of this crucial pathway in bone homeostasis. This work establishes PKG2 as a key regulator of osteoblast proliferation and post-natal bone formation.
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Affiliation(s)
- Ghania Ramdani
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
| | - Nadine Schall
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
- The Institute for Pharmacology and ToxicologyUniversity of Bonn, Bonn, Germany
| | - Hema Kalyanaraman
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
| | - Nisreen Wahwah
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
| | - Sahar Moheize
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
| | - Jenna J Lee
- Department of BioengineeringUniversity of California, San Diego, La Jolla, California, USA
| | - Robert L Sah
- Department of BioengineeringUniversity of California, San Diego, La Jolla, California, USA
| | - Alexander Pfeifer
- The Institute for Pharmacology and ToxicologyUniversity of Bonn, Bonn, Germany
| | - Darren E Casteel
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
| | - Renate B Pilz
- Department of MedicineUniversity of California, San Diego, La Jolla, California, USA
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17
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Qin L, Sankaran B, Aminzai S, Casteel DE, Kim C. Structural basis for selective inhibition of human PKG Iα by the balanol-like compound N46. J Biol Chem 2018; 293:10985-10992. [PMID: 29769318 PMCID: PMC6052212 DOI: 10.1074/jbc.ra118.002427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/11/2018] [Indexed: 12/18/2022] Open
Abstract
Activation of protein kinase G (PKG) Iα in nociceptive neurons induces long-term hyperexcitability that causes chronic pain. Recently, a derivative of the fungal metabolite balanol, N46, has been reported to inhibit PKG Iα with high potency and selectivity and attenuate thermal hyperalgesia and osteoarthritic pain. Here we determined co-crystal structures of the PKG Iα C-domain and cAMP-dependent protein kinase (PKA) Cα, each bound with N46, at 1.98 Å and 2.65 Å, respectively. N46 binds the active site with its external phenyl ring, specifically interacting with the glycine-rich loop and the αC helix. Phe-371 at the PKG Iα glycine-rich loop is oriented parallel to the phenyl ring of N46, forming a strong π-stacking interaction, whereas the analogous Phe-54 in PKA Cα rotates 30° and forms a weaker interaction. Structural comparison revealed that steric hindrance between the preceding Ser-53 and the propoxy group of the phenyl ring may explain the weaker interaction with PKA Cα. The analogous Gly-370 in PKG Iα, however, causes little steric hindrance with Phe-371. Moreover, Ile-406 on the αC helix forms a hydrophobic interaction with N46 whereas its counterpart in PKA, Thr-88, does not. Substituting these residues in PKG Iα with those in PKA Cα increases the IC50 values for N46, whereas replacing these residues in PKA Cα with those in PKG Iα reduces the IC50, consistent with our structural findings. In conclusion, our results explain the structural basis for N46-mediated selective inhibition of human PKG Iα and provide a starting point for structure-guided design of selective PKG Iα inhibitors.
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Affiliation(s)
- Liying Qin
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Banumathi Sankaran
- the Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Sahar Aminzai
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093, and
| | - Darren E Casteel
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093, and
| | - Choel Kim
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030,
- the Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030
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18
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Kalyanaraman H, Schwaerzer G, Ramdani G, Castillo F, Scott BT, Dillmann W, Sah RL, Casteel DE, Pilz RB. Protein Kinase G Activation Reverses Oxidative Stress and Restores Osteoblast Function and Bone Formation in Male Mice With Type 1 Diabetes. Diabetes 2018; 67:607-623. [PMID: 29301852 PMCID: PMC5860855 DOI: 10.2337/db17-0965] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 12/28/2017] [Indexed: 12/12/2022]
Abstract
Bone loss and fractures are underrecognized complications of type 1 diabetes and are primarily due to impaired bone formation by osteoblasts. The mechanisms leading to osteoblast dysfunction in diabetes are incompletely understood, but insulin deficiency, poor glycemic control, and hyperglycemia-induced oxidative stress likely contribute. Here we show that insulin promotes osteoblast proliferation and survival via the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) signal transduction pathway and that PKG stimulation of Akt provides a positive feedback loop. In osteoblasts exposed to high glucose, NO/cGMP/PKG signaling was reduced due in part to the addition of O-linked N-acetylglucosamine to NO synthase-3, oxidative inhibition of guanylate cyclase activity, and suppression of PKG transcription. Cinaciguat-an NO-independent activator of oxidized guanylate cyclase-increased cGMP synthesis under diabetic conditions and restored proliferation, differentiation, and survival of osteoblasts. Cinaciguat increased trabecular and cortical bone in mice with type 1 diabetes by improving bone formation and osteocyte survival. In bones from diabetic mice and in osteoblasts exposed to high glucose, cinaciguat reduced oxidative stress via PKG-dependent induction of antioxidant genes and downregulation of excess NADPH oxidase-4-dependent H2O2 production. These results suggest that cGMP-elevating agents could be used as an adjunct treatment for diabetes-associated osteoporosis.
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Gerburg Schwaerzer
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Ghania Ramdani
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Francine Castillo
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Brian T Scott
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Wolfgang Dillmann
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Robert L Sah
- Department of Bioengineering, University of California, San Diego, La Jolla, CA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA
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19
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Haushalter KJ, Casteel DE, Raffeiner A, Stefan E, Patel HH, Taylor SS. Phosphorylation of protein kinase A (PKA) regulatory subunit RIα by protein kinase G (PKG) primes PKA for catalytic activity in cells. J Biol Chem 2018; 293:4411-4421. [PMID: 29378851 PMCID: PMC5868259 DOI: 10.1074/jbc.m117.809988] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 01/23/2018] [Indexed: 01/26/2023] Open
Abstract
cAMP-dependent protein kinase (PKAc) is a pivotal signaling protein in eukaryotic cells. PKAc has two well-characterized regulatory subunit proteins, RI and RII (each having α and β isoforms), which keep the PKAc catalytic subunit in a catalytically inactive state until activation by cAMP. Previous reports showed that the RIα regulatory subunit is phosphorylated by cGMP-dependent protein kinase (PKG) in vitro, whereupon phosphorylated RIα no longer inhibits PKAc at normal (1:1) stoichiometric ratios. However, the significance of this phosphorylation as a mechanism for activating type I PKA holoenzymes has not been fully explored, especially in cellular systems. In this study, we further examined the potential of RIα phosphorylation to regulate physiologically relevant "desensitization" of PKAc activity. First, the serine 101 site of RIα was validated as a target of PKGIα phosphorylation both in vitro and in cells. Analysis of a phosphomimetic substitution in RIα (S101E) showed that modification of this site increases PKAc activity in vitro and in cells, even without cAMP stimulation. Numerous techniques were used to show that although Ser101 variants of RIα can bind PKAc, the modified linker region of the S101E mutant has a significantly reduced affinity for the PKAc active site. These findings suggest that RIα phosphorylation may be a novel mechanism to circumvent the requirement of cAMP stimulus to activate type I PKA in cells. We have thus proposed a model to explain how PKG phosphorylation of RIα creates a "sensitized intermediate" state that is in effect primed to trigger PKAc activity.
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Affiliation(s)
| | | | - Andrea Raffeiner
- the Institute of Biochemistry, University of Innsbruck, A-6020 Innsbruck, Austria, and
| | - Eduard Stefan
- the Institute of Biochemistry, University of Innsbruck, A-6020 Innsbruck, Austria, and
| | - Hemal H Patel
- Anesthesiology, and
- the Veterans Affairs San Diego Healthcare System, San Diego, California 92161
| | - Susan S Taylor
- From the Departments of Chemistry & Biochemistry,
- Pharmacology, University of California, San Diego, La Jolla, California 92093-0654
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20
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Todd Milne G, Sandner P, Lincoln KA, Harrison PC, Chen H, Wang H, Clifford H, Qian HS, Wong D, Sarko C, Fryer R, Richman J, Reinhart GA, Boustany CM, Pullen SS, Andresen H, Moltzau LR, Cataliotti A, Levy FO, Lukowski R, Frankenreiter S, Friebe A, Calamaras T, Baumgartner R, McLaughlin A, Aronovitz M, Baur W, Wang GR, Kapur N, Karas R, Blanton R, Hell S, Waldman SA, Lin JE, Colon-Gonzalez F, Kim GW, Blomain ES, Merlino D, Snook A, Erdmann J, Wobst J, Kessler T, Schunkert H, Walter U, Pagel O, Walter E, Gambaryan S, Smolenski A, Jurk K, Zahedi R, Klinger JR, Benza RL, Corris PA, Langleben D, Naeije R, Simonneau G, Meier C, Colorado P, Chang MK, Busse D, Hoeper MM, Masferrer JL, Jacobson S, Liu G, Sarno R, Bernier S, Zhang P, Todd Milne G, Flores-Costa R, Currie M, Hall K, Möhrle D, Reimann K, Wolter S, Wolters M, Mergia E, Eichert N, Geisler HS, Ruth P, Friebe A, Feil R, Zimmermann U, Koesling D, Knipper M, Rüttiger L, Tanaka Y, Okamoto A, Nojiri T, Kumazoe M, Tokudome T, Miura K, Hino J, Hosoda H, Miyazato M, Kangawa K, Kapil V, Ahluwalia A, Paolocci N, Eaton P, Campbell JC, Henning P, Franz E, Sankaran B, Herberg FW, Kim C, Wittwer M, Luo Q, Kaila V, Dames SA, Tobin A, Alam M, Rudyk O, Krasemann S, Hartmann K, Prysyazhna O, Zhang M, Zhao L, Weiss A, Schermuly R, Eaton P, Moyes AJ, Chu SM, Baliga RS, Hobbs AJ, Michalakis S, Mühlfriedel R, Schön C, Fischer DM, Wilhelm B, Zobor D, Kohl S, Peters T, Zrenner E, Bartz-Schmidt KU, Ueffing M, Wissinger B, Seeliger M, Biel M, Ranek MJ, Kokkonen KM, Lee DI, Holewinski RJ, Agrawal V, Virus C, Stevens DA, Sasaki M, Zhang H, Mannion MM, Rainer PP, Page RC, Schisler JC, Van Eyk JE, Willis MS, Kass DA, Zaccolo M, Russwurm M, Giesen J, Russwurm C, Füchtbauer EM, Koesling D, Bork NI, Nikolaev VO, Agulló L, Floor M, Villà-Freixa J, Manfra O, Calamera G, Surdo NC, Meier S, Froese A, Nikolaev VO, Zaccolo M, Levy FO, Andressen KW, Aue A, Schwiering F, Groneberg D, Friebe A, Bajraktari G, Burhenne J, Haefeli WE, Weiss J, Beck K, Voussen B, Vincent A, Parsons SP, Huizinga JD, Friebe A, Mónica FZ, Seto E, Murad F, Bian K, Burgoyne JR, Prysyazhna O, Richards D, Eaton P, Calamera G, Bjørnerem M, Ulsund AH, Kim JJ, Kim C, Levy FO, Andressen KW, Donzelli S, Goetz M, Schmidt K, Wolters M, Stathopoulou K, Prysyazhna O, Scotcher J, Dees C, Subramanian H, Butt E, Kamynina A, Bruce King S, Nikolaev VO, de Witt C, Leichert LI, Feil R, Eaton P, Cuello F, Dobrowinski H, Lehners M, Schmidt MPH, Feil R, Feil S, Wen L, Wolters M, Thunemann M, Schmidt K, Olbrich M, Langer H, Gawaz M, Friebe A, de Wit C, Feil R, Franz E, Kim JJ, Bertinetti D, Kim C, Herberg FW, Ghofrani HA, Grimminger F, Grünig E, Huang Y, Jansa P, Jing ZC, Kilpatrick D, Langleben D, Rosenkranz S, Menezes F, Fritsch A, Nikkho S, Frey R, Humbert M, Groneberg D, Aue A, Schwiering F, Friebe A, Harloff M, Reinders J, Schlossmann J, Jung J, Wales JA, Chen CY, Breci L, Weichsel A, Bernier SG, Solinga R, Sheppeck JE, Renhowe PA, Montfort WR, Qin L, Sung YJ, Casteel D, Kim C, Kollau A, Neubauer A, Schrammel A, Russwurm M, Koesling D, Mayer B, Kumazoe M, Takai M, Takeuchi C, Kadomatsu M, Hiroi S, Takamatsu K, Nojiri T, Kangawa K, Tachibana H, Opelt M, Eroglu E, Waldeck-Weiermair M, Russwurm M, Koesling D, Malli R, Graier WF, Fassett JT, Schrammel A, Mayer B, Sollie SJ, Moltzau LR, Hernandez-Valladares M, Berven F, Levy FO, Andressen KW, Nojiri T, Tokudome T, Kumazoe M, Arai M, Suzuki Y, Miura K, Hino J, Hosoda H, Miyazato M, Okumura M, Kawaoka S, Kangawa K, Peters S, Schmidt H, Selin Kenet B, Nies SH, Frank K, Wen L, Rathjen FG, Feil R, Petrova ON, Lamarre I, Négrerie M, Robinson JW, Egbert JR, Davydova J, Jaffe LA, Potter LR, Robinson JW, Blixt N, Shuhaibar LC, Warren GL, Mansky KC, Jaffe LA, Potter LR, Romoli S, Bauch T, Dröbner K, Eitner F, Ruppert M, Radovits T, Korkmaz-Icöz S, Li S, Hegedűs P, Loganathan S, Németh BT, Oláh A, Mátyás C, Benke K, Merkely B, Karck M, Szabó G, Scheib U, Broser M, Mukherjee S, Stehfest K, Gee CE, Körschen HG, Oertner TG, Hegemann P, Schmidt H, Dickey DM, Dumoulin A, Kühn R, Jaffe L, Potter LR, Rathjen FG, Schobesberger S, Wright P, Poulet C, Mansfield C, Friebe A, Harding SE, Nikolaev VO, Gorelik J, Kollau A, Opelt M, Wölkart G, Gorren ACF, Russwurm M, Koesling D, Schrammel A, Mayer B, Schwaerzer GK, Casteel DE, Dalton ND, Gu Y, Zhuang S, Milewicz DM, Peterson KL, Pilz R, Schwiering F, Aue A, Groneberg D, Friebe A, Argyriou AI, Makrynitsa G, Alexandropoulos II, Stamopoulou A, Bantzi M, Giannis A, Topouzis S, Papapetropoulos A, Spyroulias GA, Stuehr DJ, Ghosh A, Dai Y, Misra S, Tchernychev B, Jung J, Liu G, Silos-Santiago I, Hannig G, Dao VTV, Deile M, Nedvetsky PI, Güldner A, Ibarra-Alvarado C, Gödecke A, Schmidt HHHW, Vachaviolos A, Gerling A, Thunemann M, Lutz SZ, Häring HU, Krüger MA, Pichler BJ, Shipston MJ, Feil S, Feil R, Vandenwijngaert S, Ledsky CD, Agha O, Hu D, Domian IJ, Buys ES, Newton-Cheh C, Bloch DB, Voussen B, Beck K, Mauro N, Keppler J, Friebe A, Ferreira WA, Chweih H, Brito PL, Almeida CB, Penteado CFF, Saad SSO, Costa FF, Frenette PS, Brockschnieder D, Stasch JP, Sandner P, Conran N, Zimmer DP, Tobin J, Shea C, Sarno R, Long K, Jacobson S, Tang K, Germano P, Wakefield J, Banijamali A, Im GYJ, Sheppeck JE, Profy AT, Todd Milne G, Currie MG, Masferrer JL. Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications : Bamberg, Germany. 23-25 June, 2017. BMC Pharmacol Toxicol 2017; 18:64. [PMID: 29035170 PMCID: PMC5667593 DOI: 10.1186/s40360-017-0170-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Kalyanaraman H, Zhuang S, Pilz RB, Casteel DE. The activity of cGMP-dependent protein kinase Iα is not directly regulated by oxidation-induced disulfide formation at cysteine 43. J Biol Chem 2017; 292:8262-8268. [PMID: 28360102 DOI: 10.1074/jbc.c117.787358] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 03/28/2017] [Indexed: 12/20/2022] Open
Abstract
The type I cGMP-dependent protein kinases (PKGs) are key regulators of smooth muscle tone, cardiac hypertrophy, and other physiological processes. The two isoforms PKGIα and PKGIβ are thought to have unique functions because of their tissue-specific expression, different cGMP affinities, and isoform-specific protein-protein interactions. Recently, a non-canonical pathway of PKGIα activation has been proposed, in which PKGIα is activated in a cGMP-independent fashion via oxidation of Cys43, resulting in disulfide formation within the PKGIα N-terminal dimerization domain. A "redox-dead" knock-in mouse containing a C43S mutation exhibits phenotypes consistent with decreased PKGIα signaling, but the detailed mechanism of oxidation-induced PKGIα activation is unknown. Therefore, we examined oxidation-induced activation of PKGIα, and in contrast to previous findings, we observed that disulfide formation at Cys43 does not directly activate PKGIα in vitro or in intact cells. In transfected cells, phosphorylation of Ras homolog gene family member A (RhoA) and vasodilator-stimulated phosphoprotein was increased in response to 8-CPT-cGMP treatment, but not when disulfide formation in PKGIα was induced by H2O2 Using purified enzymes, we found that the Cys43 oxidation had no effect on basal kinase activity or Km and Vmax values; however, PKGIα containing the C43S mutation was less responsive to cGMP-induced activation. This reduction in cGMP affinity may in part explain the PKGIα loss-of-function phenotype of the C43S knock-in mouse. In conclusion, disulfide formation at Cys43 does not directly activate PKGIα, and the C43S-mutant PKGIα has a higher Ka for cGMP. Our results highlight that mutant enzymes should be carefully biochemically characterized before making in vivo inferences.
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Shunhui Zhuang
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, California 92093.
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Kalyanaraman H, Ramdani G, Joshua J, Schall N, Boss GR, Cory E, Sah RL, Casteel DE, Pilz RB. A Novel, Direct NO Donor Regulates Osteoblast and Osteoclast Functions and Increases Bone Mass in Ovariectomized Mice. J Bone Miner Res 2017; 32:46-59. [PMID: 27391172 PMCID: PMC5199609 DOI: 10.1002/jbmr.2909] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 07/01/2016] [Accepted: 07/05/2016] [Indexed: 01/06/2023]
Abstract
Most US Food and Drug Administration (FDA)-approved treatments for osteoporosis target osteoclastic bone resorption. Only PTH derivatives improve bone formation, but they have drawbacks, and novel bone-anabolic agents are needed. Nitrates, which generate NO, improved BMD in estrogen-deficient rats and may improve bone formation markers and BMD in postmenopausal women. However, nitrates are limited by induction of oxidative stress and development of tolerance, and may increase cardiovascular mortality after long-term use. Here we studied nitrosyl-cobinamide (NO-Cbi), a novel, direct NO-releasing agent, in a mouse model of estrogen deficiency-induced osteoporosis. In murine primary osteoblasts, NO-Cbi increased intracellular cGMP, Wnt/β-catenin signaling, proliferation, and osteoblastic gene expression, and protected cells from apoptosis. Correspondingly, in intact and ovariectomized (OVX) female C57Bl/6 mice, NO-Cbi increased serum cGMP concentrations, bone formation, and osteoblastic gene expression, and in OVX mice, it prevented osteocyte apoptosis. NO-Cbi reduced osteoclasts in intact mice and prevented the known increase in osteoclasts in OVX mice, partially through a reduction in the RANKL/osteoprotegerin gene expression ratio, which regulates osteoclast differentiation, and partially through direct inhibition of osteoclast differentiation, observed in vitro in the presence of excess RANKL. The positive NO effects in osteoblasts were mediated by cGMP/protein kinase G (PKG), but some of the osteoclast-inhibitory effects appeared to be cGMP-independent. NO-Cbi increased trabecular bone mass in both intact and OVX mice, consistent with its in vitro effects on osteoblasts and osteoclasts. NO-Cbi is a novel direct NO-releasing agent that, in contrast to nitrates, does not generate oxygen radicals, and combines anabolic and antiresorptive effects in bone, making it an excellent candidate for treating osteoporosis. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0652
| | - Ghania Ramdani
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0652
| | - Jisha Joshua
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0652
| | - Nadine Schall
- Institute of Pharmacology and Toxicology, University of Bonn, 53105 Bonn, Germany
| | - Gerry R. Boss
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0652
| | - Esther Cory
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0652
| | - Robert L. Sah
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0652
| | - Darren E. Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0652
| | - Renate B. Pilz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0652
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Sahu D, Gupta S, Hau AM, Nakashima K, Leivo MZ, Searles SC, Elson P, Bomalaski JS, Casteel DE, Boss GR, Hansel DE. Argininosuccinate Synthetase 1 Loss in Invasive Bladder Cancer Regulates Survival through General Control Nonderepressible 2 Kinase-Mediated Eukaryotic Initiation Factor 2α Activity and Is Targetable by Pegylated Arginine Deiminase. Am J Pathol 2016; 187:200-213. [PMID: 27979310 DOI: 10.1016/j.ajpath.2016.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 08/10/2016] [Accepted: 09/01/2016] [Indexed: 11/29/2022]
Abstract
Loss of argininosuccinate synthetase 1 (ASS1), a key enzyme for arginine synthesis, occurs in many cancers, making cells dependent on extracellular arginine and targetable by the arginine-degrading enzyme pegylated arginine deiminase (ADI-PEG 20). We evaluated ASS1 expression and effects of ASS1 loss in bladder cancer which, despite affecting >70,000 people in the United States annually, has limited therapies. ASS1 loss was identified in conventional and micropapillary urothelial carcinoma, small cell, and squamous cell carcinoma subtypes of invasive bladder cancer, as well as in T24, J82, and UM-UC-3 but not in 5637, RT112, and RT4 cell lines. ASS1-deficient cells showed preferential sensitivity to ADI-PEG 20, evidenced by decreased colony formation, reduced cell viability, and increased sub-G1 fractions. ADI-PEG 20 induced general control nonderepressible 2-dependent eukaryotic initiation factor 2α phosphorylation and activating transcription factor 4 and C/EBP homologous protein up-regulation, associated with caspase-independent apoptosis and autophagy. These effects were ablated with selective siRNA silencing of these proteins. ASS1 overexpression in UM-UC-3 or ASS1 silencing in RT112 cells reversed these effects. ADI-PEG 20 treatment of mice bearing contralateral flank UM-UC-3 and RT112 xenografts selectively arrested tumor growth in UM-UC-3 xenografts, which had reduced tumor size, reduced Ki-67, and increased terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining. This suggests that ASS1 loss occurs in invasive bladder cancer and is targetable by ADI-PEG 20.
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Affiliation(s)
- Divya Sahu
- Department of Pathology, University of California at San Diego, La Jolla, California
| | - Sounak Gupta
- Department of Pathology, University of California at San Diego, La Jolla, California
| | - Andrew M Hau
- Department of Pathology, University of California at San Diego, La Jolla, California
| | - Kazufumi Nakashima
- Department of Pathology, University of California at San Diego, La Jolla, California
| | - Mariah Z Leivo
- Department of Pathology, University of California at San Diego, La Jolla, California
| | - Stephen C Searles
- Department of Pathology, University of California at San Diego, La Jolla, California
| | - Paul Elson
- Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | | | - Darren E Casteel
- Department of Medicine, University of California at San Diego, La Jolla, California
| | - Gerry R Boss
- Department of Medicine, University of California at San Diego, La Jolla, California
| | - Donna E Hansel
- Department of Pathology, University of California at San Diego, La Jolla, California.
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Cividini F, Scott BT, Dai A, Han W, Suarez J, Diaz-Juarez J, Diemer T, Casteel DE, Dillmann WH. O-GlcNAcylation of 8-Oxoguanine DNA Glycosylase (Ogg1) Impairs Oxidative Mitochondrial DNA Lesion Repair in Diabetic Hearts. J Biol Chem 2016; 291:26515-26528. [PMID: 27816939 DOI: 10.1074/jbc.m116.754481] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/03/2016] [Indexed: 11/06/2022] Open
Abstract
mtDNA damage in cardiac myocytes resulting from increased oxidative stress is emerging as an important factor in the pathogenesis of diabetic cardiomyopathy. A prevalent lesion that occurs in mtDNA damage is the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG), which can cause mutations when not repaired properly by 8-oxoguanine DNA glycosylase (Ogg1). Although the mtDNA repair machinery has been described in cardiac myocytes, the regulation of this repair has been incompletely investigated. Here we report that the hearts of type 1 diabetic mice, despite having increased Ogg1 protein levels, had significantly lower Ogg1 activity than the hearts of control, non-type 1 diabetic mice. In diabetic hearts, we further observed increased levels of 8-OHdG and an increased amount of mtDNA damage. Interestingly, Ogg1 was found to be highly O-GlcNAcylated in diabetic mice compared with controls. In vitro experiments demonstrated that O-GlcNAcylation inhibits Ogg1 activity, which could explain the mtDNA lesion accumulation observed in vivo Reducing Ogg1 O-GlcNAcylation in vivo by introducing a dominant negative O-GlcNAc transferase mutant (F460A) restored Ogg1 enzymatic activity and, consequently, reduced 8-OHdG and mtDNA damage despite the adverse hyperglycemic milieu. Taken together, our results implicate hyperglycemia-induced O-GlcNAcylation of Ogg1 in increased mtDNA damage and, therefore, provide a new plausible biochemical mechanism for diabetic cardiomyopathy.
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Affiliation(s)
- Federico Cividini
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Brian T Scott
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Anzhi Dai
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Wenlong Han
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Jorge Suarez
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Julieta Diaz-Juarez
- the Department of Pharmacology, Instituto Nacional de Cardiología, Juan Badiano 41, Barrio Belisario Domínguez Secc XVI, 14080 Tlalpan, DF, Mexico
| | - Tanja Diemer
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Darren E Casteel
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
| | - Wolfgang H Dillmann
- From the Department of Medicine, University of California, San Diego, La Jolla, California 92093-0671 and
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Kim JJ, Lorenz R, Arold ST, Reger AS, Sankaran B, Casteel DE, Herberg FW, Kim C. Crystal Structure of PKG I:cGMP Complex Reveals a cGMP-Mediated Dimeric Interface that Facilitates cGMP-Induced Activation. Structure 2016; 24:710-720. [PMID: 27066748 DOI: 10.1016/j.str.2016.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 01/21/2016] [Accepted: 03/04/2016] [Indexed: 10/22/2022]
Abstract
Cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) is a key regulator of smooth muscle and vascular tone and represents an important drug target for treating hypertensive diseases and erectile dysfunction. Despite its importance, its activation mechanism is not fully understood. To understand the activation mechanism, we determined a 2.5 Å crystal structure of the PKG I regulatory (R) domain bound with cGMP, which represents the activated state. Although we used a monomeric domain for crystallization, the structure reveals that two R domains form a symmetric dimer where the cGMP bound at high-affinity pockets provide critical dimeric contacts. Small-angle X-ray scattering and mutagenesis support this dimer model, suggesting that the dimer interface modulates kinase activation. Finally, structural comparison with the homologous cyclic AMP-dependent protein kinase reveals that PKG is drastically different from protein kinase A in its active conformation, suggesting a novel activation mechanism for PKG.
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Affiliation(s)
- Jeong Joo Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Biochemistry, University of Kassel, Kassel, Hesse 34132, Germany
| | - Robin Lorenz
- Department of Biochemistry, University of Kassel, Kassel, Hesse 34132, Germany
| | - Stefan T Arold
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center, Division of Biological and Environmental Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - Albert S Reger
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Friedrich W Herberg
- Department of Biochemistry, University of Kassel, Kassel, Hesse 34132, Germany
| | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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Campbell JC, Kim JJ, Li KY, Huang GY, Reger AS, Matsuda S, Sankaran B, Link TM, Yuasa K, Ladbury JE, Casteel DE, Kim C. Structural Basis of Cyclic Nucleotide Selectivity in cGMP-dependent Protein Kinase II. J Biol Chem 2016; 291:5623-5633. [PMID: 26769964 PMCID: PMC4786703 DOI: 10.1074/jbc.m115.691303] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/13/2016] [Indexed: 02/04/2023] Open
Abstract
Membrane-bound cGMP-dependent protein kinase (PKG) II is a key regulator of bone growth, renin secretion, and memory formation. Despite its crucial physiological roles, little is known about its cyclic nucleotide selectivity mechanism due to a lack of structural information. Here, we find that the C-terminal cyclic nucleotide binding (CNB-B) domain of PKG II binds cGMP with higher affinity and selectivity when compared with its N-terminal CNB (CNB-A) domain. To understand the structural basis of cGMP selectivity, we solved co-crystal structures of the CNB domains with cyclic nucleotides. Our structures combined with mutagenesis demonstrate that the guanine-specific contacts at Asp-412 and Arg-415 of the αC-helix of CNB-B are crucial for cGMP selectivity and activation of PKG II. Structural comparison with the cGMP selective CNB domains of human PKG I and Plasmodium falciparum PKG (PfPKG) shows different contacts with the guanine moiety, revealing a unique cGMP selectivity mechanism for PKG II.
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Affiliation(s)
- James C Campbell
- From the Structural and Computational Biology and Molecular Biophysics Program
| | - Jeong Joo Kim
- Department of Pharmacology, and; the Department of Biochemistry, University of Kassel, Kassel, Hesse 34132, Germany
| | - Kevin Y Li
- the Department of Biochemistry & Cell Biology, Rice University, Houston, Texas 77005
| | - Gilbert Y Huang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | | | - Shinya Matsuda
- the Department of Biological Science and Technology, the University of Tokushima Graduate School, Tokushima 770-8506, Japan
| | - Banumathi Sankaran
- the Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Todd M Link
- the Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, and
| | - Keizo Yuasa
- the Department of Biological Science and Technology, the University of Tokushima Graduate School, Tokushima 770-8506, Japan
| | - John E Ladbury
- From the Structural and Computational Biology and Molecular Biophysics Program,; the Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, and
| | - Darren E Casteel
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Choel Kim
- From the Structural and Computational Biology and Molecular Biophysics Program,; Department of Pharmacology, and; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030,.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kalyanaraman H, Schwappacher R, Joshua J, Zhuang S, Scott BT, Klos M, Casteel DE, Frangos JA, Dillmann W, Boss GR, Pilz RB. Nongenomic thyroid hormone signaling occurs through a plasma membrane-localized receptor. Sci Signal 2014; 7:ra48. [PMID: 24847117 DOI: 10.1126/scisignal.2004911] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Thyroid hormone (TH) is essential for vertebrate development and the homeostasis of most adult tissues, including bone. TH stimulates target gene expression through the nuclear thyroid receptors TRα and TRβ; however, TH also has rapid, transcription-independent (nongenomic) effects. We found a previously uncharacterized plasma membrane-bound receptor that was necessary and sufficient for nongenomic TH signaling in several cell types. We determined that this receptor is generated by translation initiation from an internal methionine of TRα, which produces a transcriptionally incompetent protein that is palmitoylated and associates with caveolin-containing plasma membrane domains. TH signaling through this receptor stimulated a pro-proliferative and pro-survival program by increasing the intracellular concentrations of calcium, nitric oxide (NO), and cyclic guanosine monophosphate (cGMP), which led to the sequential activation of protein kinase G II (PKGII), the tyrosine kinase Src, and extracellular signal-regulated kinase (ERK) and Akt signaling. Hypothyroid mice exhibited a cGMP-deficient state with impaired bone formation and increased apoptosis of osteocytes, which was rescued by a direct stimulator of guanylate cyclase. Our results link nongenomic TH signaling to a previously uncharacterized membrane-bound receptor, and identify NO synthase, guanylate cyclase, and PKGII as TH effectors that activate kinase cascades to regulate cell survival and proliferation.
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Affiliation(s)
- Hema Kalyanaraman
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Raphaela Schwappacher
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Jisha Joshua
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Shunhui Zhuang
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Brian T Scott
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Matthew Klos
- Department of Surgery, University of California, San Diego, San Diego, CA 92093, USA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - John A Frangos
- La Jolla Bioengineering Institute, La Jolla, CA 92121, USA
| | - Wolfgang Dillmann
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Gerry R Boss
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, San Diego, CA 92093, USA.
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Huang GY, Kim JJ, Reger AS, Lorenz R, Moon EW, Zhao C, Casteel DE, Bertinetti D, Vanschouwen B, Selvaratnam R, Pflugrath JW, Sankaran B, Melacini G, Herberg FW, Kim C. Structural basis for cyclic-nucleotide selectivity and cGMP-selective activation of PKG I. Structure 2013; 22:116-24. [PMID: 24239458 DOI: 10.1016/j.str.2013.09.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/18/2013] [Accepted: 09/23/2013] [Indexed: 10/26/2022]
Abstract
Cyclic guanosine monophosphate (cGMP) and cyclic AMP (cAMP)-dependent protein kinases (PKG and PKA) are closely related homologs, and the cyclic nucleotide specificity of each kinase is crucial for keeping the two signaling pathways segregated, but the molecular mechanism of cyclic nucleotide selectivity is unknown. Here, we report that the PKG Iβ C-terminal cyclic nucleotide binding domain (CNB-B) is highly selective for cGMP binding, and we have solved crystal structures of CNB-B with and without bound cGMP. These structures, combined with a comprehensive mutagenic analysis, allowed us to identify Leu296 and Arg297 as key residues that mediate cGMP selectivity. In addition, by comparing the cGMP bound and unbound structures, we observed large conformational changes in the C-terminal helices in response to cGMP binding, which were stabilized by recruitment of Tyr351 as a "capping residue" for cGMP. The observed rearrangements of the C-terminal helices provide a mechanical insight into release of the catalytic domain and kinase activation.
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Affiliation(s)
- Gilbert Y Huang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jeong Joo Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Albert S Reger
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robin Lorenz
- Department of Biochemistry, University of Kassel, Kassel 34132, Germany
| | - Eui-Whan Moon
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chi Zhao
- Department of Chemistry, Rice University, Houston, TX 77005, USA
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Bryan Vanschouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - Rajeevan Selvaratnam
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | | | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Building 6R2100, Berkeley, CA 94720, USA
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | | | - Choel Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA.
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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] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Huang GY, Kim JJ, Reger AS, Lorenz R, Moon EW, Zhao C, Casteel DE, Bertinetti D, VanSchouwen B, Selvaratnam R, Pflugrath JW, Sankaran B, Melacini G, Herberg FW, Kim C. Structures of human PKG reveal cGMP-selectived activation mechanisms. BMC Pharmacol Toxicol 2013. [PMCID: PMC3765643 DOI: 10.1186/2050-6511-14-s1-o16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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33
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Casteel DE, Turner S, Schwappacher R, Rangaswami H, Su-Yuo J, Zhuang S, Boss GR, Pilz RB. Rho isoform-specific interaction with IQGAP1 promotes breast cancer cell proliferation and migration. J Biol Chem 2012; 287:38367-78. [PMID: 22992742 DOI: 10.1074/jbc.m112.377499] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We performed a proteomics screen for Rho isoform-specific binding proteins to clarify the tumor-promoting effects of RhoA and C that contrast with the tumor-suppressive effects of RhoB. We found that the IQ-motif-containing GTPase-activating protein IQGAP1 interacts directly with GTP-bound, prenylated RhoA and RhoC, but not with RhoB. Co-immunoprecipitation of IQGAP1 with endogenous RhoA/C was enhanced when RhoA/C were activated by epidermal growth factor (EGF) or transfection of a constitutively active guanine nucleotide exchange factor (GEF). Overexpression of IQGAP1 increased GTP-loading of RhoA/C, while siRNA-mediated depletion of IQGAP1 prevented endogenous RhoA/C activation by growth factors. IQGAP1 knockdown also reduced the amount of GTP bound to GTPase-deficient RhoA/C mutants, suggesting that IQGAP enhances Rho activation by GEF(s) or stabilizes Rho-GTP. IQGAP1 depletion in MDA-MB-231 breast cancer cells blocked EGF- and RhoA-induced stimulation of DNA synthesis. Infecting cells with adenovirus encoding constitutively active RhoA(L63) and measuring absolute amounts of RhoA-GTP in infected cells demonstrated that the lack of RhoA(L63)-induced DNA synthesis in IQGAP1-depleted cells was not due to reduced GTP-bound RhoA. These data suggested that IQGAP1 functions downstream of RhoA. Overexpression of IQGAP1 in MDA-MB-231 cells increased DNA synthesis irrespective of siRNA-mediated RhoA knockdown. Breast cancer cell motility was increased by expressing a constitutively-active RhoC(V14) mutant or overexpressing IQGAP1. EGF- or RhoC-induced migration required IQGAP1, but IQGAP1-stimulated migration independently of RhoC, placing IQGAP1 downstream of RhoC. We conclude that IQGAP1 acts both upstream of RhoA/C, regulating their activation state, and downstream of RhoA/C, mediating their effects on breast cancer cell proliferation and migration, respectively.
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Affiliation(s)
- Darren E Casteel
- Department of Medicine and Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
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Rangaswami H, Schwappacher R, Marathe N, Casteel DE, Haas B, Pfeifer A, Shattil S, Boss G, Pilz RB. Src activation by cGMP/PKG II in osteoblasts: characterization of a mechano-sensitive signalling complex. BMC Pharmacol 2011. [PMCID: PMC3363182 DOI: 10.1186/1471-2210-11-s1-o24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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36
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Osborne BW, Wu J, McFarland CJ, Nickl CK, Sankaran B, Casteel DE, Woods VL, Kornev AP, Taylor SS, Dostmann WR. Crystal structure of cGMP-dependent protein kinase reveals novel site of interchain communication. Structure 2011; 19:1317-27. [PMID: 21893290 PMCID: PMC3168983 DOI: 10.1016/j.str.2011.06.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 06/08/2011] [Accepted: 06/13/2011] [Indexed: 11/27/2022]
Abstract
The cGMP-dependent protein kinase (PKG) serves as an integral component of second messenger signaling in a number of biological contexts including cell differentiation, memory, and vasodilation. PKG is homodimeric and large conformational changes accompany cGMP binding. However, the structure of PKG and the molecular mechanisms associated with protomer communication following cGMP-induced activation remain unknown. Here, we report the 2.5 Å crystal structure of a regulatory domain construct (aa 78-355) containing both cGMP binding sites of PKG Iα. A distinct and segregated architecture with an extended central helix separates the two cGMP binding domains. Additionally, a previously uncharacterized helical domain (switch helix) promotes the formation of a hydrophobic interface between protomers. Mutational disruption of this interaction in full-length PKG implicates the switch helix as a critical site of dimer communication in PKG biology. These results offer new structural insight into the mechanism of allosteric PKG activation.
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Affiliation(s)
- Brent W. Osborne
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05405
| | - Jian Wu
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Caitlin J. McFarland
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05405
| | - Christian K. Nickl
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05405
| | - Banumathi Sankaran
- The Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Darren E. Casteel
- Department of Medicine and Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Virgil L. Woods
- Department of Medicine and Cancer Center, University of California, San Diego, La Jolla, California 92093
| | - Alexandr P. Kornev
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093
| | - Susan S. Taylor
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093
| | - Wolfgang R. Dostmann
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05405
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Kim JJ, Casteel DE, Huang G, Kwon TH, Ren RK, Zwart P, Headd JJ, Brown NG, Chow DC, Palzkill T, Kim C. The crystal structures of PKG Iβ (92-227) with cGMP and cAMP reveal the molecular details of cyclic-nucleotide binding. BMC Pharmacol 2011. [PMCID: PMC3363171 DOI: 10.1186/1471-2210-11-s1-o14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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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. Int J Mass Spectrom 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kim JJ, Casteel DE, Huang G, Kwon TH, Ren RK, Zwart P, Headd JJ, Brown NG, Chow DC, Palzkill T, Kim C. Co-crystal structures of PKG Iβ (92-227) with cGMP and cAMP reveal the molecular details of cyclic-nucleotide binding. PLoS One 2011; 6:e18413. [PMID: 21526164 PMCID: PMC3080414 DOI: 10.1371/journal.pone.0018413] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 02/28/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cyclic GMP-dependent protein kinases (PKGs) are central mediators of the NO-cGMP signaling pathway and phosphorylate downstream substrates that are crucial for regulating smooth muscle tone, platelet activation, nociception and memory formation. As one of the main receptors for cGMP, PKGs mediate most of the effects of cGMP elevating drugs, such as nitric oxide-releasing agents and phosphodiesterase inhibitors which are used for the treatment of angina pectoris and erectile dysfunction, respectively. METHODOLOGY/PRINCIPAL FINDINGS We have investigated the mechanism of cyclic nucleotide binding to PKG by determining crystal structures of the amino-terminal cyclic nucleotide-binding domain (CNBD-A) of human PKG I bound to either cGMP or cAMP. We also determined the structure of CNBD-A in the absence of bound nucleotide. The crystal structures of CNBD-A with bound cAMP or cGMP reveal that cAMP binds in either syn or anti configurations whereas cGMP binds only in a syn configuration, with a conserved threonine residue anchoring both cyclic phosphate and guanine moieties. The structure of CNBD-A in the absence of bound cyclic nucleotide was similar to that of the cyclic nucleotide bound structures. Surprisingly, isothermal titration calorimetry experiments demonstrated that CNBD-A binds both cGMP and cAMP with a relatively high affinity, showing an approximately two-fold preference for cGMP. CONCLUSIONS/SIGNIFICANCE Our findings suggest that CNBD-A binds cGMP in the syn conformation through its interaction with Thr193 and an unusual cis-peptide forming residues Leu172 and Cys173. Although these studies provide the first structural insights into cyclic nucleotide binding to PKG, our ITC results show only a two-fold preference for cGMP, indicating that other domains are required for the previously reported cyclic nucleotide selectivity.
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Affiliation(s)
- Jeong Joo Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Darren E. Casteel
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Gilbert Huang
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Taek Hun Kwon
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ronnie Kuo Ren
- Rice University, Houston, Texas, United States of America
| | - Peter Zwart
- The Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Jeffrey J. Headd
- Computational Crystallography Initiative, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Nicholas Gene Brown
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Dar-Chone Chow
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Timothy Palzkill
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Rangaswami H, Schwappacher R, Marathe N, Zhuang S, Casteel DE, Haas B, Chen Y, Pfeifer A, Kato H, Shattil S, Boss GR, Pilz RB. Cyclic GMP and protein kinase G control a Src-containing mechanosome in osteoblasts. Sci Signal 2010; 3:ra91. [PMID: 21177494 DOI: 10.1126/scisignal.2001423] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mechanical stimulation is crucial for bone growth and remodeling, and fluid shear stress promotes anabolic responses in osteoblasts through multiple second messengers, including nitric oxide (NO). NO triggers production of cyclic guanosine 3',5'-monophosphate (cGMP), which in turn activates protein kinase G (PKG). We found that the NO-cGMP-PKG signaling pathway activates Src in mechanically stimulated osteoblasts to initiate a proliferative response. PKGII was necessary for Src activation, a process that also required the interaction of Src with β₃ integrins and dephosphorylation of Src by a complex containing the phosphatases SHP-1 (Src homology 2 domain-containing tyrosine phosphatase 1) and SHP-2. PKGII directly phosphorylated and stimulated SHP-1 activity, and fluid shear stress triggered the recruitment of PKGII, Src, SHP-1, and SHP-2 to a mechanosome containing β₃ integrins. PKGII-null mice showed defective Src and ERK (extracellular signal-regulated kinase) signaling in osteoblasts and decreased ERK-dependent gene expression in bone. Our findings reveal a convergence of NO-cGMP-PKG and integrin signaling and establish a previously unknown mechanism of Src activation. These results support the use of PKG-activating drugs to mimic the anabolic effects of mechanical stimulation of bone in the treatment of osteoporosis.
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Affiliation(s)
- Hema Rangaswami
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Casteel DE, Smith-Nguyen EV, Sankaran B, Spraggon G, Hampton EN, Pilz RB, Taylor SS, Kim C. The first crystal structure of cyclic GMP-dependent protein kinase Iβ dimerization/docking domain reveals molecular details of isoform-specific anchoring. BMC Pharmacol 2009. [PMCID: PMC3313374 DOI: 10.1186/1471-2210-9-s1-p6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Casteel DE, Zhuang S, Zeng Y, Perrino FW, Boss GR, Goulian M, Pilz RB. A DNA polymerase-{alpha}{middle dot}primase cofactor with homology to replication protein A-32 regulates DNA replication in mammalian cells. J Biol Chem 2008; 284:5807-18. [PMID: 19119139 DOI: 10.1074/jbc.m807593200] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
alpha-Accessory factor (AAF) stimulates the activity of DNA polymerase-alpha.primase, the only enzyme known to initiate DNA replication in eukaryotic cells ( Goulian, M., Heard, C. J., and Grimm, S. L. (1990) J. Biol. Chem. 265, 13221-13230 ). We purified the AAF heterodimer composed of 44- and 132-kDa subunits from cultured cells and identified full-length cDNA clones using amino acid sequences from internal peptides. AAF-132 demonstrated no homologies to known proteins; AAF-44, however, is evolutionarily related to the 32-kDa subunit of replication protein A (RPA-32) and contains an oligonucleotide/oligosaccharide-binding (OB) fold domain similar to the OB fold domains of RPA involved in single-stranded DNA binding. Epitope-tagged versions of AAF-44 and -132 formed a complex in intact cells, and purified recombinant AAF-44 bound to single-stranded DNA and stimulated DNA primase activity only in the presence of AAF-132. Mutations in conserved residues within the OB fold of AAF-44 reduced DNA binding activity of the AAF-44.AAF-132 complex. Immunofluorescence staining of AAF-44 and AAF-132 in S phase-enriched HeLa cells demonstrated punctate nuclear staining, and AAF co-localized with proliferating cell nuclear antigen, a marker for replication foci containing DNA polymerase-alpha.primase and RPA. Small interfering RNA-mediated depletion of AAF-44 in tumor cell lines inhibited [methyl-(3)H]thymidine uptake into DNA but did not affect cell viability. We conclude that AAF shares structural and functional similarities with RPA-32 and regulates DNA replication, consistent with its ability to increase polymerase-alpha.primase template affinity and stimulate both DNA primase and polymerase-alpha activities in vitro.
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Affiliation(s)
- Darren E Casteel
- Department of Medicine and Cancer Center of the University of California, San Diego, La Jolla, California 92093, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kim C, Smith‐Nguyen EV, Casteel DE, Sankaran B, Spraggon G, Pilz RB, Taylor SS. The first crystal structure of cyclic GMP‐dependent protein kinase Iβ dimerization domain reveals the molecular features of an extended leucine/isoleucine zipper. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.828.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | | | - Susan S. Taylor
- HHMILa JollaCA
- Depts of Chem & Biochem, & PharmaUCSDLa JollaCA
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Zhang T, Zhuang S, Casteel DE, Looney DJ, Boss GR, Pilz RB. A cysteine-rich LIM-only protein mediates regulation of smooth muscle-specific gene expression by cGMP-dependent protein kinase. J Biol Chem 2007; 282:33367-33380. [PMID: 17878170 DOI: 10.1074/jbc.m707186200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vascular smooth muscle cells (VSMCs) undergo phenotypic modulation, changing from a differentiated, contractile to a de-differentiated, synthetic phenotype; the change is associated with decreased expression of smooth muscle (SM)-specific genes and loss of cGMP-dependent protein kinase (PKG), but transfection of PKG into de-differentiated VSMCs restores SM-specific gene expression. We show that small interference RNA-mediated down-regulation or pharmacologic inhibition of PKG reduced SM-specific gene expression in differentiated VSMCs and provide a mechanism for cGMP/PKG regulation of SM-specific genes involving the cysteine-rich LIM-only protein CRP4. PKG associated with CRP4 and phosphorylated the protein in intact cells. CRP4 had no intrinsic transcriptional activity, but exhibited adaptor function, because it acted synergistically with serum response factor (SRF) and GATA6 to activate the SM-alpha-actin promoter. cGMP stimulation of the promoter required PKG and CRP4 co-expression with SRF and GATA6. A phosphorylation-deficient mutant CRP4 and a CRP4 deletion mutant deficient in PKG binding did not support cGMP/PKG stimulation of the SM-alpha-actin promoter. In the presence of wild-type but not mutant CRP4, cGMP/PKG enhanced SRF binding to a probe encoding the distal SM-alpha-actin promoter CArG (CC(AT)(6)GG) element. CRP4 and SRF associated with CArG elements of endogenous SM-specific genes in intact chromatin. Small interference RNA-mediated down-regulation of CRP4 prevented the positive effects of cGMP/PKG on SM-specific gene expression. In the presence of CRP4, cGMP/PKG increased SRF- and GATA6-dependent expression of endogenous SM-specific genes in pluripotent 10T1/2 cells. Thus, CRP4 mediates cGMP/PKG stimulation of SM-specific gene expression, and PKG plays an important role in regulating the phenotype of VSMCs.
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Affiliation(s)
- Tong Zhang
- Department of Medicine, University of California, San Diego, California, 92093
| | - Shunhui Zhuang
- Department of Medicine, University of California, San Diego, California, 92093
| | - Darren E Casteel
- Department of Medicine, University of California, San Diego, California, 92093
| | - David J Looney
- Department of Medicine, University of California, San Diego, California, 92093; Veterans Administration Medical Center, La Jolla, California 92161
| | - Gerry R Boss
- Department of Medicine, University of California, San Diego, California, 92093; Cancer Center, University of California, San Diego, California 92093
| | - Renate B Pilz
- Department of Medicine, University of California, San Diego, California, 92093; Cancer Center, University of California, San Diego, California 92093.
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Zhang T, Zhuang S, Casteel DE, Pilz RB. A cysteine-rich LIM-only protein mediates regulation of smooth muscle-specific gene expression by cGMP-dependent protein kinase. BMC Pharmacol 2007. [DOI: 10.1186/1471-2210-7-s1-p68] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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49
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Casteel DE, Boss GR, Pilz RB. Identification of the interface between cGMP-dependent protein kinase Ibeta and its interaction partners TFII-I and IRAG reveals a common interaction motif. J Biol Chem 2005; 280:38211-8. [PMID: 16166082 DOI: 10.1074/jbc.m507021200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-protein interactions have emerged as an important mechanism providing for specificity in cellular signal transduction. Two splice variants of type I cGMP-dependent protein kinase (PKG Ialpha and Ibeta) differ only in their N-terminal approximately 100 amino acids, which mediate binding to different target proteins. PKG Ibeta, but not Ialpha, binds to the general transcriptional regulator TFII-I and the inositol 1,4,5-trisphosphate receptor-associated PKG substrate IRAG. Using a combination of site-directed mutagenesis and in vitro binding assays, we identified a group of acidic amino acids in the N-terminal leucine zipper dimerization domain of PKG Ibeta required for its binding to both TFII-I and IRAG. Small clusters of basic amino acids in possible alpha-helical regions in TFII-I and IRAG were found to mediate their interaction with PKG Ibeta. Mutation of two negatively charged residues in the PKG Ibeta leucine zipper (D26K/E31R) to positively charged residues, found in corresponding positions in PKG Ialpha, completely abrogated binding to TFII-I and IRAG without disrupting PKG dimerization. Mutation of specific basic residues in TFII-I or IRAG abolished binding of the full-length proteins to PKG Ibeta in intact cells. Based on these results, we propose a model for specific PKG Ibeta interaction with target proteins.
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MESH Headings
- Alternative Splicing
- Amino Acid Motifs
- Amino Acid Sequence
- Animals
- COS Cells
- Calcium Channels/chemistry
- Cattle
- Cell Line
- Chlorocebus aethiops
- Cloning, Molecular
- Cyclic GMP-Dependent Protein Kinases/metabolism
- DNA/chemistry
- DNA/metabolism
- Dimerization
- Electrophoresis, Polyacrylamide Gel
- Glutathione Transferase/metabolism
- Humans
- Immunoblotting
- Inositol 1,4,5-Trisphosphate Receptors
- Leucine/chemistry
- Membrane Proteins
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mutation
- Phosphoproteins/metabolism
- Protein Binding
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Receptors, Cytoplasmic and Nuclear/chemistry
- Signal Transduction
- Static Electricity
- Transcription Factors, TFII/metabolism
- Transcription, Genetic
- Transfection
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Affiliation(s)
- Darren E Casteel
- Department of Medicine and Cancer Center, University of California at San Diego, La Jolla, California 92093-0652, USA
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Abstract
Methylmalonyl-CoA mutase is a key enzyme in intermediary metabolism, and children deficient in enzyme activity have severe metabolic acidosis. We found that nitric oxide (NO) inhibits methylmalonyl-CoA mutase activity in rodent cell extracts. The inhibition of enzyme activity occurred within minutes and was not prevented by thiols, suggesting that enzyme inhibition was not occurring via NO reaction with cysteine residues to form nitrosothiol groups. Enzyme inhibition was dependent on the presence of substrate, implying that NO was reacting with cobalamin(II) (Cbl(II)) and/or the deoxyadenosyl radical (.CH(2)-Ado), both of which are generated from the co-factor of the enzyme, 5'-deoxyadenosyl-cobalamin (AdoCbl), on substrate binding. Consistent with this hypothesis was the finding that high micromolar concentrations (> or =600 microm) of oxygen also inhibited enzyme activity. To study the mechanism of NO reaction with AdoCbl, we simulated the enzymatic reaction by photolyzing AdoCbl, and found that even at low NO concentrations, NO reacted with both the generated Cbl(II) and .CH(2)-Ado indicating that NO could effectively compete with the back formation of AdoCbl. Thus, NO inhibition of methylmalonyl-CoA mutase appeared to be from the reaction of NO with both AdoCbl intermediates (Cbl(II) and .CH(2)-Ado) generated during the enzymatic reaction. The inhibition of methylmalonyl-CoA mutase by NO was likely of physiological relevance because a NO donor inhibited enzyme activity in intact cells, and scavenging NO from cells or inhibiting cellular NO synthesis increased methylmalonyl-CoA mutase activity when measured subsequently in cell extracts.
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Affiliation(s)
- Amanpreet Kambo
- Department of Medicine, and Cancer Center, University of California, 9500 Gilman Dr., La Jolla, California 92093-0652, USA
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