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Kimura S, Lok J, Gelman IH, Lo EH, Arai K. Role of A-Kinase Anchoring Protein 12 in the Central Nervous System. J Clin Neurol 2023; 19:329-337. [PMID: 37417430 DOI: 10.3988/jcn.2023.0095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 07/08/2023] Open
Abstract
A-kinase anchoring protein (AKAP) 12 is a scaffolding protein that anchors various signaling proteins to the plasma membrane. These signaling proteins include protein kinase A, protein kinase C, protein phosphatase 2B, Src-family kinases, cyclins, and calmodulin, which regulate their respective signaling pathways. AKAP12 expression is observed in the neurons, astrocytes, endothelial cells, pericytes, and oligodendrocytes of the central nervous system (CNS). Its physiological roles include promoting the development of the blood-brain barrier, maintaining white-matter homeostasis, and even regulating complex cognitive functions such as long-term memory formation. Under pathological conditions, dysregulation of AKAP12 expression levels may be involved in the pathology of neurological diseases such as ischemic brain injury and Alzheimer's disease. This minireview aimed to summarize the current literature on the role of AKAP12 in the CNS.
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Affiliation(s)
- Shintaro Kimura
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Life Science Research Center, Gifu University, Gifu, Japan
| | - Josephine Lok
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Critical Care Medicine, Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Irwin H Gelman
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Ken Arai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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Li H. Physiologic and pathophysiologic roles of AKAP12. Sci Prog 2022; 105:368504221109212. [PMID: 35775596 PMCID: PMC10450473 DOI: 10.1177/00368504221109212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A kinase anchoring protein (AKAP) 12 is a scaffolding protein that improves the specificity and efficiency of spatiotemporal signal through assembling intracellular signal proteins into a specific complex. AKAP12 is a negative mitogenic regulator that plays an important role in controlling cytoskeletal architecture, maintaining endothelial integrity, regulating glial function and forming blood-brain barrier (BBB) and blood retinal barrier (BRB). Moreover, elevated or reduced AKAP12 contributes to a variety of diseases. Complex connections between AKAP12 and various diseases including chronic liver diseases (CLDs), inflammatory diseases and a series of cancers will be tried to delineate in this paper. We first describe the expression, distribution and physiological function of AKAP12. Then we summarize the current knowledge of different connections between AKAP12 expression and various diseases. Some research groups have found paradoxical roles of AKAP12 in different diseases and further confirmation is needed. This paper aims to assess the role of AKAP12 in physiology and diseases to help lay the foundation for the design of small molecules for specific AKAP12 to correct the pathological signal defects.
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Affiliation(s)
- Hui Li
- Central Laboratory, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, P. R. China
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Reversible lysine fatty acylation of an anchoring protein mediates adipocyte adrenergic signaling. Proc Natl Acad Sci U S A 2022; 119:2119678119. [PMID: 35149557 PMCID: PMC8851525 DOI: 10.1073/pnas.2119678119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2021] [Indexed: 01/05/2023] Open
Abstract
N-myristoylation on glycine is an irreversible modification that has long been recognized to govern protein localization and function. In contrast, the biological roles of lysine myristoylation remain ill-defined. We demonstrate that the cytoplasmic scaffolding protein, gravin-α/A kinase-anchoring protein 12, is myristoylated on two lysine residues embedded in its carboxyl-terminal protein kinase A (PKA) binding domain. Histone deacetylase 11 (HDAC11) docks to an adjacent region of gravin-α and demyristoylates these sites. In brown and white adipocytes, lysine myristoylation of gravin-α is required for signaling via β2- and β3-adrenergic receptors (β-ARs), which are G protein-coupled receptors (GPCRs). Lysine myristoylation of gravin-α drives β-ARs to lipid raft membrane microdomains, which results in PKA activation and downstream signaling that culminates in protective thermogenic gene expression. These findings define reversible lysine myristoylation as a mechanism for controlling GPCR signaling and highlight the potential of inhibiting HDAC11 to manipulate adipocyte phenotypes for therapeutic purposes.
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Qasim H, McConnell BK. AKAP12 Signaling Complex: Impacts of Compartmentalizing cAMP-Dependent Signaling Pathways in the Heart and Various Signaling Systems. J Am Heart Assoc 2020; 9:e016615. [PMID: 32573313 PMCID: PMC7670535 DOI: 10.1161/jaha.120.016615] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Heart failure is a complex clinical syndrome, represented as an impairment in ventricular filling and myocardial blood ejection. As such, heart failure is one of the leading causes of death in the United States. With a mortality rate of 1 per 8 individuals and a prevalence of 6.2 million Americans, it has been projected that heart failure prevalence will increase by 46% by 2030. Cardiac remodeling (a general determinant of heart failure) is regulated by an extensive network of intertwined intracellular signaling pathways. The ability of signalosomes (molecular signaling complexes) to compartmentalize several cellular pathways has been recently established. These signalosome signaling complexes provide an additional level of specificity to general signaling pathways by regulating the association of upstream signals with downstream effector molecules. In cardiac myocytes, the AKAP12 (A‐kinase anchoring protein 12) scaffolds a large signalosome that orchestrates spatiotemporal signaling through stabilizing pools of phosphatases and kinases. Predominantly upon β‐AR (β2‐adrenergic‐receptor) stimulation, the AKAP12 signalosome is recruited near the plasma membrane and binds tightly to β‐AR. Thus, one major function of AKAP12 is compartmentalizing PKA (protein kinase A) signaling near the plasma membrane. In addition, it is involved in regulating desensitization, downregulation, and recycling of β‐AR. In this review, the critical roles of AKAP12 as a scaffold protein in mediating signaling downstream GPCRs (G protein–coupled receptor) are discussed with an emphasis on its reported and potential roles in cardiovascular disease initiation and progression.
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Affiliation(s)
- Hanan Qasim
- Department of Pharmacological and Pharmaceutical Sciences College of Pharmacy University of Houston TX
| | - Bradley K McConnell
- Department of Pharmacological and Pharmaceutical Sciences College of Pharmacy University of Houston TX
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Kim JG, Kim HH, Bae SJ. Akap12beta supports asymmetric heart development via modulating the Kupffer’s vesicle formation in zebrafish. BMB Rep 2019. [PMID: 31383248 PMCID: PMC6726206 DOI: 10.5483/bmbrep.2019.52.8.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The vertebrate body plan is accomplished by left-right asymmetric organ development and the heart is a representative asymmetric internal organ which jogs to the left-side. Kupffer’s vesicle (KV) is a spherical left-right organizer during zebrafish embryogenesis and is derived from a cluster of dorsal forerunner cells (DFCs). Cadherin1 is required for collective migration of a DFC cluster and failure of DFC collective migration by Cadherin1 decrement causes KV malformation which results in defective heart laterality. Recently, loss of function mutation of A-kinase anchoring protein 12 (AKAP12) is reported as a high-risk gene in congenital heart disease patients. In this study, we demonstrated the role of akap12β in asymmetric heart development. The akap12β, one of the akap12 isoforms, was expressed in DFCs which give rise to KV and akap12β-deficient zebrafish embryos showed defective heart laterality due to the fragmentation of DFC clusters which resulted in KV malformation. DFC-specific loss of akap12β also led to defective heart laterality as a consequence of the failure of collective migration by cadherin1 reduction. Exogenous akap12β mRNA not only restored the defective heart laterality but also increased cadherin1 expression in akap12β morphant zebrafish embryos. Taken together, these findings provide the first experimental evidence that akap12β regulates heart laterality via cadherin1.
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Affiliation(s)
- Jeong-gyun Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Korea
| | - Hyun-Ho Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Korea
- Biological and Medical Device Evaluation Team, Korea Testing & Research Institute, Gwacheon 13810, Korea
| | - Sung-Jin Bae
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Korea
- Korean Medicine Research Center for Healthy Aging, Pusan National Univerity, Yangsan 50612, Korea
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Wild AR, Dell'Acqua ML. Potential for therapeutic targeting of AKAP signaling complexes in nervous system disorders. Pharmacol Ther 2017; 185:99-121. [PMID: 29262295 DOI: 10.1016/j.pharmthera.2017.12.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A common feature of neurological and neuropsychiatric disorders is a breakdown in the integrity of intracellular signal transduction pathways. Dysregulation of ion channels and receptors in the cell membrane and the enzymatic mediators that link them to intracellular effectors can lead to synaptic dysfunction and neuronal death. However, therapeutic targeting of these ubiquitous signaling elements can lead to off-target side effects due to their widespread expression in multiple systems of the body. A-kinase anchoring proteins (AKAPs) are multivalent scaffolding proteins that compartmentalize a diverse range of receptor and effector proteins to streamline signaling within nanodomain signalosomes. A number of essential neurological processes are known to critically depend on AKAP-directed signaling and an understanding of the role AKAPs play in nervous system disorders has emerged in recent years. Selective targeting of AKAP protein-protein interactions may be a means to uncouple pathologically active signaling pathways in neurological disorders with a greater degree of specificity. In this review we will discuss the role of AKAPs in both regulating normal nervous system function and dysfunction associated with disease, and the potential for therapeutic targeting of AKAP signaling complexes.
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Affiliation(s)
- Angela R Wild
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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Rabelo K, Trugilho MRO, Costa SM, Pereira BAS, Moreira OC, Ferreira ATS, Carvalho PC, Perales J, Alves AMB. The effect of the dengue non-structural 1 protein expression over the HepG2 cell proteins in a proteomic approach. J Proteomics 2016; 152:339-354. [PMID: 27826075 DOI: 10.1016/j.jprot.2016.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 10/14/2016] [Accepted: 11/01/2016] [Indexed: 01/01/2023]
Abstract
Dengue is an important mosquito borne viral disease in the world. Dengue virus (DENV) encodes a polyprotein, which is cleaved in ten proteins, including the non-structural protein 1 (NS1). In this work, we analyzed the effect of NS1 expression in one hepatic cell line, HepG2, through a shotgun proteomic approach. Cells were transfected with pcENS1 plasmid, which encodes the DENV2 NS1 protein, or the controls pcDNA3 (negative control) and pMAXGFP (GFP, a protein unrelated to dengue). Expression of NS1 was detected by immunofluorescence, western blot and flow cytometry. We identified 14,138 peptides that mapped to 4,756 proteins in all analyzed conditions. We found 41 and 81 differentially abundant proteins when compared to cells transfected with plasmids pcDNA3 and pMAXGFP, respectively. Besides, 107 proteins were detected only in the presence of NS1. We identified clusters of proteins involved mainly in mRNA process and viral RNA replication. Down regulation expression of one protein (MARCKS), identified by the proteomic analysis, was also confirmed by real time PCR in HepG2 cells infected with DENV2. Identification of proteins modulated by the presence of NS1 may improve our understanding of its role in virus infection and pathogenesis, contributing to development of new therapies and vaccines. BIOLOGICAL SIGNIFICANCE Dengue is an important viral disease, with epidemics in tropical and subtropical regions of the world. The disease is complex, with different manifestations, in which the liver is normally affected. The NS1 is found in infected cells associated with plasma membrane and secreted into the circulation as a soluble multimer. This protein is essential for virus viability, although its function is not elucidated. Some reports indicate that the NS1 can be used as a protective antigen for the development of a dengue vaccine, while others suggest its involvement in viral pathogenesis. In this work, we report an in-depth comprehensive proteomic profiling resulting from the presence of NS1 in HepG2 cells. These results can contribute to a better understanding of the NS1 role during infection.
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Affiliation(s)
- Kíssila Rabelo
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Monique R O Trugilho
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Simone M Costa
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Bernardo A S Pereira
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Otacílio C Moreira
- Laboratory of Molecular Biology and Endemic Diseases, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - André T S Ferreira
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Paulo C Carvalho
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz, Paraná, Brazil
| | - Jonas Perales
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Ada M B Alves
- Laboratory of Biotechnology and Physiology of Viral Infections, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil.
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The molecular effect of metastasis suppressors on Src signaling and tumorigenesis: new therapeutic targets. Oncotarget 2016; 6:35522-41. [PMID: 26431493 PMCID: PMC4742122 DOI: 10.18632/oncotarget.5849] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/15/2015] [Indexed: 02/07/2023] Open
Abstract
A major problem for cancer patients is the metastasis of cancer cells from the primary tumor. This involves: (1) migration through the basement membrane; (2) dissemination via the circulatory system; and (3) invasion into a secondary site. Metastasis suppressors, by definition, inhibit metastasis at any step of the metastatic cascade. Notably, Src is a non-receptor, cytoplasmic, tyrosine kinase, which becomes aberrantly activated in many cancer-types following stimulation of plasma membrane receptors (e.g., receptor tyrosine kinases and integrins). There is evidence of a prominent role of Src in tumor progression-related events such as the epithelial–mesenchymal transition (EMT) and the development of metastasis. However, the precise molecular interactions of Src with metastasis suppressors remain unclear. Herein, we review known metastasis suppressors and summarize recent advances in understanding the mechanisms of how these proteins inhibit metastasis through modulation of Src. Particular emphasis is bestowed on the potent metastasis suppressor, N-myc downstream regulated gene 1 (NDRG1) and its interactions with the Src signaling cascade. Recent studies demonstrated a novel mechanism through which NDRG1 plays a significant role in regulating cancer cell migration by inhibiting Src activity. Moreover, we discuss the rationale for targeting metastasis suppressor genes as a sound therapeutic modality, and we review several examples from the literature where such strategies show promise. Collectively, this review summarizes the essential interactions of metastasis suppressors with Src and their effects on progression of cancer metastasis. Moreover, interesting unresolved issues regarding these proteins as well as their potential as therapeutic targets are also discussed.
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Jarrett SG, Wolf Horrell EM, D'Orazio JA. AKAP12 mediates PKA-induced phosphorylation of ATR to enhance nucleotide excision repair. Nucleic Acids Res 2016; 44:10711-10726. [PMID: 27683220 PMCID: PMC5159552 DOI: 10.1093/nar/gkw871] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 09/16/2016] [Accepted: 09/21/2016] [Indexed: 12/30/2022] Open
Abstract
Loss-of-function in melanocortin 1 receptor (MC1R), a GS protein-coupled receptor that regulates signal transduction through cAMP and protein kinase A (PKA) in melanocytes, is a major inherited melanoma risk factor. Herein, we report a novel cAMP-mediated response for sensing and responding to UV-induced DNA damage regulated by A-kinase-anchoring protein 12 (AKAP12). AKAP12 is identified as a necessary participant in PKA-mediated phosphorylation of ataxia telangiectasia mutated and Rad3-related (ATR) at S435, a post-translational event required for cAMP-enhanced nucleotide excision repair (NER). Moreover, UV exposure promotes ATR-directed phosphorylation of AKAP12 at S732, which promotes nuclear translocation of AKAP12–ATR-pS435. This complex subsequently recruits XPA to UV DNA damage and enhances 5′ strand incision. Preventing AKAP12's interaction with PKA or with ATR abrogates ATR-pS435 accumulation, delays recruitment of XPA to UV-damaged DNA, impairs NER and increases UV-induced mutagenesis. Our results define a critical role for AKAP12 as an UV-inducible scaffold for PKA-mediated ATR phosphorylation, and identify a repair complex consisting of AKAP12–ATR-pS435-XPA at photodamage, which is essential for cAMP-enhanced NER.
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Affiliation(s)
- Stuart G Jarrett
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Erin M Wolf Horrell
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA.,Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - John A D'Orazio
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY 40536, USA .,Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA.,Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, KY 40536, USA.,Department of Pharmacology and Nutritional Science, University of Kentucky College of Medicine, Lexington, KY 40536, USA.,Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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Miano JM, Zhu QM, Lowenstein CJ. A CRISPR Path to Engineering New Genetic Mouse Models for Cardiovascular Research. Arterioscler Thromb Vasc Biol 2016; 36:1058-75. [PMID: 27102963 PMCID: PMC4882230 DOI: 10.1161/atvbaha.116.304790] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 04/06/2016] [Indexed: 12/26/2022]
Abstract
Previous efforts to target the mouse genome for the addition, subtraction, or substitution of biologically informative sequences required complex vector design and a series of arduous steps only a handful of laboratories could master. The facile and inexpensive clustered regularly interspaced short palindromic repeats (CRISPR) method has now superseded traditional means of genome modification such that virtually any laboratory can quickly assemble reagents for developing new mouse models for cardiovascular research. Here, we briefly review the history of CRISPR in prokaryotes, highlighting major discoveries leading to its formulation for genome modification in the animal kingdom. Core components of CRISPR technology are reviewed and updated. Practical pointers for 2-component and 3-component CRISPR editing are summarized with many applications in mice including frameshift mutations, deletion of enhancers and noncoding genes, nucleotide substitution of protein-coding and gene regulatory sequences, incorporation of loxP sites for conditional gene inactivation, and epitope tag integration. Genotyping strategies are presented and topics of genetic mosaicism and inadvertent targeting discussed. Finally, clinical applications and ethical considerations are addressed as the biomedical community eagerly embraces this astonishing innovation in genome editing to tackle previously intractable questions.
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Affiliation(s)
- Joseph M Miano
- From the Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY (J.M.M., Q.M.Z., C.J.L.); and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA (Q.M.Z.).
| | - Qiuyu Martin Zhu
- From the Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY (J.M.M., Q.M.Z., C.J.L.); and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA (Q.M.Z.)
| | - Charles J Lowenstein
- From the Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY (J.M.M., Q.M.Z., C.J.L.); and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA (Q.M.Z.)
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Wilhelm T, Lipka DB, Witte T, Wierzbinska JA, Fluhr S, Helf M, Mücke O, Claus R, Konermann C, Nöllke P, Niemeyer CM, Flotho C, Plass C. Epigenetic silencing of AKAP12 in juvenile myelomonocytic leukemia. Epigenetics 2016; 11:110-9. [PMID: 26891149 DOI: 10.1080/15592294.2016.1145327] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A-kinase anchor protein 12 (AKAP12) is a regulator of protein kinase A and protein kinase C signaling, acting downstream of RAS. Epigenetic silencing of AKAP12 has been demonstrated in different cancer entities and this has been linked to the process of tumorigenesis. Here, we used quantitative high-resolution DNA methylation measurement by MassARRAY to investigate epigenetic regulation of all three AKAP12 promoters (i.e., α, β, and γ) within a large cohort of juvenile myelomonocytic leukemia (JMML) patient samples. The AKAP12α promoter shows DNA hypermethylation in JMML samples, which is associated with decreased AKAP12α expression. Promoter methylation of AKAP12α correlates with older age at diagnosis, elevated levels of fetal hemoglobin and poor prognosis. In silico screening for transcription factor binding motifs around the sites of most pronounced methylation changes in the AKAP12α promoter revealed highly significant scores for GATA-2/-1 sequence motifs. Both transcription factors are known to be involved in the haematopoietic differentiation process. Methylation of a reporter construct containing this region resulted in strong suppression of AKAP12 promoter activity, suggesting that DNA methylation might be involved in the aberrant silencing of the AKAP12 promoter in JMML. Exposure to DNMT- and HDAC-inhibitors reactivates AKAP12α expression in vitro, which could potentially be a mechanism underlying clinical treatment responses upon demethylating therapy. Together, these data provide evidence for epigenetic silencing of AKAP12α in JMML and further emphasize the importance of dysregulated RAS signaling in JMML pathogenesis.
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Affiliation(s)
- Thomas Wilhelm
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Daniel B Lipka
- b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Tania Witte
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Justyna A Wierzbinska
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.,b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Silvia Fluhr
- c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.,d Hermann Staudinger Graduate School, University of Freiburg , Freiburg , Germany
| | - Monika Helf
- b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Oliver Mücke
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.,b Regulation of Cellular Differentiation Group, Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Rainer Claus
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.,e Department of Medicine , Division of Hematology, Oncology and Stem Cell Transplantation, University of Freiburg Medical Center , Freiburg , Germany
| | - Carolin Konermann
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany
| | - Peter Nöllke
- c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany
| | - Charlotte M Niemeyer
- c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.,f German Cancer Consortium (DKTK)
| | - Christian Flotho
- c Department of Pediatrics and Adolescent Medicine , Division of Pediatric Hematology-Oncology, University of Freiburg Medical Center , Freiburg , Germany.,f German Cancer Consortium (DKTK)
| | - Christoph Plass
- a Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center , Heidelberg , Germany.,f German Cancer Consortium (DKTK)
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12
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Kumbrink J, Soni S, Laumbacher B, Loesch B, Kirsch KH. Identification of Novel Crk-associated Substrate (p130Cas) Variants with Functionally Distinct Focal Adhesion Kinase Binding Activities. J Biol Chem 2015; 290:12247-55. [PMID: 25805500 DOI: 10.1074/jbc.m115.649947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Indexed: 01/08/2023] Open
Abstract
Elevated levels of p130(Cas) (Crk-associated substrate)/BCAR1 (breast cancer antiestrogen resistance 1 gene) are associated with aggressiveness of breast tumors. Following phosphorylation of its substrate domain, p130(Cas) promotes the integration of protein complexes involved in multiple signaling pathways and mediates cell proliferation, adhesion, and migration. In addition to the known BCAR1-1A (wild-type) and 1C variants, we identified four novel BCAR1 mRNA variants, generated by alternative first exon usage (1B, 1B1, 1D, and 1E). Exons 1A and 1C encode for four amino acids (aa), whereas 1D and 1E encode for 22 aa and 1B1 encodes for 50 aa. Exon 1B is non-coding, resulting in a truncated p130(Cas) protein (Cas1B). BCAR1-1A, 1B1, and variant 1C mRNAs were ubiquitously expressed in cell lines and a survey of human tissues, whereas 1B, 1D, and 1E expression was more restricted. Reconstitution of all isoforms except for 1B in p130(Cas)-deficient murine fibroblasts induced lamellipodia formation and membrane ruffling, which was unrelated to the substrate domain phosphorylation status. The longer isoforms exhibited increased binding to focal adhesion kinase (FAK), a molecule important for migration and adhesion. The shorter 1B isoform exhibited diminished FAK binding activity and significantly reduced migration and invasion. In contrast, the longest variant 1B1 established the most efficient FAK binding and greatly enhanced migration. Our results indicate that the p130(Cas) exon 1 variants display altered functional properties. The truncated variant 1B and the longer isoform 1B1 may contribute to the diverse effects of p130(Cas) on cell biology and therefore will be the target of future studies.
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Affiliation(s)
- Joerg Kumbrink
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Shefali Soni
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Barbara Laumbacher
- the Immunotherapy Research Center, Pettenkoferstrasse 8, 80336 Munich, Germany, and
| | - Barbara Loesch
- Immunis e.V., Pettenkoferstrasse 8, 80336 Munich, Germany
| | - Kathrin H Kirsch
- From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118,
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Hypoxic induction of AKAP12 variant 2 shifts PKA-mediated protein phosphorylation to enhance migration and metastasis of melanoma cells. Proc Natl Acad Sci U S A 2015; 112:4441-6. [PMID: 25792458 DOI: 10.1073/pnas.1418164112] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Scaffold proteins are critical hubs within cells that have the ability to modulate upstream signaling molecules and their downstream effectors to fine-tune biological responses. Although they can serve as focal points for association of signaling molecules and downstream pathways that regulate tumorigenesis, little is known about how the tumor microenvironment affects the expression and activity of scaffold proteins. This study demonstrates that hypoxia, a common element of solid tumors harboring low oxygen levels, regulates expression of a specific variant of the scaffold protein AKAP12 (A-kinase anchor protein 12), AKAP12v2, in metastatic melanoma. In turn, through a kinome-wide phosphoproteomic and MS study, we demonstrate that this scaffolding protein regulates a shift in protein kinase A (PKA)-mediated phosphorylation events under hypoxia, causing alterations in tumor cell invasion and migration in vitro, as well as metastasis in an in vivo orthotopic model of melanoma. Mechanistically, the shift in AKAP12-dependent PKA-mediated phosphorylations under hypoxia is due to changes in AKAP12 localization vs. structural differences between its two variants. Importantly, our work defines a mechanism through which a scaffold protein can be regulated by the tumor microenvironment and further explains how a tumor cell can coordinate many critical signaling pathways that are essential for tumor growth through one individual scaffolding protein.
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Ko HK, Guo LW, Su B, Gao L, Gelman IH. Suppression of chemotaxis by SSeCKS via scaffolding of phosphoinositol phosphates and the recruitment of the Cdc42 GEF, Frabin, to the leading edge. PLoS One 2014; 9:e111534. [PMID: 25356636 PMCID: PMC4214753 DOI: 10.1371/journal.pone.0111534] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 09/28/2014] [Indexed: 01/09/2023] Open
Abstract
Chemotaxis is controlled by interactions between receptors, Rho-family GTPases, phosphatidylinositol 3-kinases, and cytoskeleton remodeling proteins. We investigated how the metastasis suppressor, SSeCKS, attenuates chemotaxis. Chemotaxis activity inversely correlated with SSeCKS levels in mouse embryo fibroblasts (MEF), DU145 and MDA-MB-231 cancer cells. SSeCKS loss induced chemotactic velocity and linear directionality, correlating with replacement of leading edge lamellipodia with fascin-enriched filopodia-like extensions, the formation of thickened longitudinal F-actin stress fibers reaching to filopodial tips, relative enrichments at the leading edge of phosphatidylinositol (3,4,5)P3 (PIP3), Akt, PKC-ζ, Cdc42-GTP and active Src (SrcpoY416), and a loss of Rac1. Leading edge lamellipodia and chemotaxis inhibition in SSeCKS-null MEF could be restored by full-length SSeCKS or SSeCKS deleted of its Src-binding domain (ΔSrc), but not by SSeCKS deleted of its three MARCKS (myristylated alanine-rich C kinase substrate) polybasic domains (ΔPBD), which bind PIP2 and PIP3. The enrichment of activated Cdc42 in SSeCKS-null leading edge filopodia correlated with recruitment of the Cdc42-specific guanine nucleotide exchange factor, Frabin, likely recruited via multiple PIP2/3-binding domains. Frabin knockdown in SSeCKS-null MEF restores leading edge lamellipodia and chemotaxis inhibition. However, SSeCKS failed to co-immunoprecipitate with Rac1, Cdc42 or Frabin. Consistent with the notion that chemotaxis is controlled by SSeCKS-PIP (vs. -Src) scaffolding activity, constitutively-active phosphatidylinositol 3-kinase could override the ability of the Src inhibitor, SKI-606, to suppress chemotaxis and filopodial enrichment of Frabin in SSeCKS-null MEF. Our data suggest a role for SSeCKS in controlling Rac1 vs. Cdc42-induced cellular dynamics at the leading chemotactic edge through the scaffolding of phospholipids and signal mediators, and through the reorganization of the actin cytoskeleton controlling directional movement.
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Affiliation(s)
- Hyun-Kyung Ko
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Li-wu Guo
- Div. of Genetic & Reproductive Toxicology, National Center for Toxicological Research, Jefferson, Arkansas, United States of America
| | - Bing Su
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Lingqiu Gao
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Irwin H. Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
- * E-mail:
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15
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Cha JH, Wee HJ, Seo JH, Ahn BJ, Park JH, Yang JM, Lee SW, Lee OH, Lee HJ, Gelman IH, Arai K, Lo EH, Kim KW. Prompt meningeal reconstruction mediated by oxygen-sensitive AKAP12 scaffolding protein after central nervous system injury. Nat Commun 2014; 5:4952. [PMID: 25229625 DOI: 10.1038/ncomms5952] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 08/11/2014] [Indexed: 11/09/2022] Open
Abstract
The meninges forms a critical epithelial barrier, which protects the central nervous system (CNS), and therefore its prompt reconstruction after CNS injury is essential for reducing neuronal damage. Meningeal cells migrate into the lesion site after undergoing an epithelial-mesenchymal transition (EMT) and repair the impaired meninges. However, the molecular mechanisms of meningeal EMT remain largely undefined. Here we show that TGF-β1 and retinoic acid (RA) released from the meninges, together with oxygen tension, could constitute the mechanism for rapid meningeal reconstruction. AKAP12 is an effector of this mechanism, and its expression in meningeal cells is regulated by integrated upstream signals composed of TGF-β1, RA and oxygen tension. Functionally, AKAP12 modulates meningeal EMT by regulating the TGF-β1-non-Smad-SNAI1 signalling pathway. Collectively, TGF-β1, RA and oxygen tension can modulate the dynamic change in AKAP12 expression, causing prompt meningeal reconstruction after CNS injury by regulating the transition between the epithelial and mesenchymal states of meningeal cells.
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Affiliation(s)
- Jong-Ho Cha
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Hee-Jun Wee
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Ji Hae Seo
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Bum Ju Ahn
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Ji-Hyeon Park
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Jun-Mo Yang
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
| | - Sae-Won Lee
- Department of Internal Medicine, Innovative Research Institute for Cell Therapy, Seoul National University Hospital, Seoul 110-799, Korea
| | - Ok-Hee Lee
- Department of Biomedical Science, CHA University, Seoul 135-081, Korea
| | - Hyo-Jong Lee
- College of Pharmacy, Inje University, Gimhae 621-749, Korea
| | - Irwin H Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
| | - Ken Arai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA
| | - Kyu-Won Kim
- 1] SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea [2] Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul 151-742, Korea
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Ma Y, Ambannavar R, Stephans J, Jeong J, Dei Rossi A, Liu ML, Friedman AJ, Londry JJ, Abramson R, Beasley EM, Baker J, Levy S, Qu K. Fusion transcript discovery in formalin-fixed paraffin-embedded human breast cancer tissues reveals a link to tumor progression. PLoS One 2014; 9:e94202. [PMID: 24727804 PMCID: PMC3984112 DOI: 10.1371/journal.pone.0094202] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 03/12/2014] [Indexed: 01/09/2023] Open
Abstract
The identification of gene fusions promises to play an important role in personalized cancer treatment decisions. Many rare gene fusion events have been identified in fresh frozen solid tumors from common cancers employing next-generation sequencing technology. However the ability to detect transcripts from gene fusions in RNA isolated from formalin-fixed paraffin-embedded (FFPE) tumor tissues, which exist in very large sample repositories for which disease outcome is known, is still limited due to the low complexity of FFPE libraries and the lack of appropriate bioinformatics methods. We sought to develop a bioinformatics method, named gFuse, to detect fusion transcripts in FFPE tumor tissues. An integrated, cohort based strategy has been used in gFuse to examine single-end 50 base pair (bp) reads generated from FFPE RNA-Sequencing (RNA-Seq) datasets employing two breast cancer cohorts of 136 and 76 patients. In total, 118 fusion events were detected transcriptome-wide at base-pair resolution across the 212 samples. We selected 77 candidate fusions based on their biological relevance to cancer and supported 61% of these using TaqMan assays. Direct sequencing of 19 of the fusion sequences identified by TaqMan confirmed them. Three unique fused gene pairs were recurrent across the 212 patients with 6, 3, 2 individuals harboring these fusions respectively. We show here that a high frequency of fusion transcripts detected at the whole transcriptome level correlates with poor outcome (P<0.0005) in human breast cancer patients. This study demonstrates the ability to detect fusion transcripts as biomarkers from archival FFPE tissues, and the potential prognostic value of the fusion transcripts detected.
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Affiliation(s)
- Yan Ma
- Genomic Health Inc., Redwood City, California, United States of America
| | | | - James Stephans
- Genomic Health Inc., Redwood City, California, United States of America
| | - Jennie Jeong
- Genomic Health Inc., Redwood City, California, United States of America
| | - Andrew Dei Rossi
- Genomic Health Inc., Redwood City, California, United States of America
| | - Mei-Lan Liu
- Genomic Health Inc., Redwood City, California, United States of America
| | - Adam J. Friedman
- Genomic Health Inc., Redwood City, California, United States of America
| | - Jason J. Londry
- Genomic Health Inc., Redwood City, California, United States of America
| | - Richard Abramson
- Genomic Health Inc., Redwood City, California, United States of America
| | - Ellen M. Beasley
- Genomic Health Inc., Redwood City, California, United States of America
| | - Joffre Baker
- Genomic Health Inc., Redwood City, California, United States of America
| | - Samuel Levy
- Genomic Health Inc., Redwood City, California, United States of America
| | - Kunbin Qu
- Genomic Health Inc., Redwood City, California, United States of America
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Schott MB, Grove B. Receptor-mediated Ca2+ and PKC signaling triggers the loss of cortical PKA compartmentalization through the redistribution of gravin. Cell Signal 2013; 25:2125-35. [PMID: 23838009 DOI: 10.1016/j.cellsig.2013.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/01/2013] [Indexed: 10/26/2022]
Abstract
A-Kinase Anchoring Proteins (AKAPs) direct the flow of cellular information by positioning multiprotein signaling complexes into proximity with effector proteins. However, certain AKAPs are not stationary but can undergo spatiotemporal redistribution in response to stimuli. Gravin, a 300kD AKAP that intersects with a diverse signaling array, is localized to the plasma membrane but has been shown to translocate to the cytosol following the elevation of intracellular calcium ([Ca(2+)]i). Despite the potential for gravin redistribution to impact multiple signaling pathways, the dynamics of this event remain poorly understood. In this study, quantitative microscopy of cells expressing gravin-EGFP revealed that Ca(2+) elevation caused the complete translocation of gravin from the cell cortex to the cytosol in as little as 60s of treatment with ionomycin or thapsigargin. In addition, receptor mediated signaling was also shown to cause gravin redistribution following ATP treatment, and this event required both [Ca(2+)]i elevation and PKC activation. To understand the mechanism for Ca(2+) mediated gravin dynamics, deletion of calmodulin-binding domains revealed that a fourth putative calmodulin binding domain called CB4 (a.a. 670-694) is critical for targeting gravin to the cell cortex despite its location downstream of gravin's membrane-targeting domains, which include an N-terminal myristoylation site and three polybasic domains. Finally, confocal microscopy of cells co-transfected with gravin-EYFP and PKA RII-ECFP revealed that gravin redistribution mediated by ionomycin, thapsigargin, and ATP each triggered the gravin-dependent loss of PKA localized at the cell cortex. Our results support the hypothesis that gravin redistribution regulates cross-talk between PKA-dependent signaling and receptor-mediated events involving Ca(2+) and PKC.
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Affiliation(s)
- Micah B Schott
- Department of Basic Sciences, UND School of Medicine and Health Sciences, 501 N Columbia Rd., Grand Forks, ND 58202-9037, USA
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Suppression of tumor and metastasis progression through the scaffolding functions of SSeCKS/Gravin/AKAP12. Cancer Metastasis Rev 2013; 31:493-500. [PMID: 22684366 DOI: 10.1007/s10555-012-9360-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Scaffolding proteins such as SSeCKS/Gravin/AKAP12 ("AKAP12") are thought to control oncogenic signaling pathways by regulating key mediators in a spatiotemporal manner. The downregulation of AKAP12 in many human cancers, often associated with promoter hypermethylation, or the loss of its locus at 6q24-25.2, correlates with progression to malignancy and metastasis. The forced re-expression of AKAP12 in cancer cell lines suppresses in vitro parameters of oncogenic growth, invasiveness, and cell motility through its ability to scaffold protein kinase C (PKC), F-actin, cyclins, Src, and phosphoinositides, and possibly through additional scaffolding domains for PKA, calmodulin, β1,4-galactosyltransferase-polypeptide-1, β2-adrenergic receptors, and cAMP-specific 3',5'-cyclic phosphodiesterase 4D. Moreover, AKAP12 re-expression in tumor models results in metastasis suppression through the inhibition of Src-regulated, VEGF-mediated neovascularization at distal sites. The current review will describe the emerging understanding of how AKAP12 regulates cellular senescence and oncogenic progression at the level of tumor cells and tumor-associated microenvironment via its multiple scaffolding functions.
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Abstract
Vascular smooth muscle cells have attracted considerable interest as a model for a flexible program of gene expression. This cell type arises throughout the embryo body plan via poorly understood signaling cascades that direct the expression of transcription factors and microRNAs which, in turn, orchestrate the activation of contractile genes collectively defining this cell lineage. The discovery of myocardin and its close association with serum response factor has represented a major break-through for the molecular understanding of vascular smooth muscle cell differentiation. Retinoids have been shown to improve the outcome of vessel wall remodeling following injury and have provided further insights into the molecular circuitry that defines the vascular smooth muscle cell phenotype. This review summarizes the progress to date in each of these areas of vascular smooth muscle cell biology.
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Gravin orchestrates protein kinase A and β2-adrenergic receptor signaling critical for synaptic plasticity and memory. J Neurosci 2013; 32:18137-49. [PMID: 23238728 DOI: 10.1523/jneurosci.3612-12.2012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A kinase-anchoring proteins (AKAPs) organize compartmentalized pools of protein kinase A (PKA) to enable localized signaling events within neurons. However, it is unclear which of the many expressed AKAPs in neurons target PKA to signaling complexes important for long-lasting forms of synaptic plasticity and memory storage. In the forebrain, the anchoring protein gravin recruits a signaling complex containing PKA, PKC, calmodulin, and PDE4D (phosphodiesterase 4D) to the β2-adrenergic receptor. Here, we show that mice lacking the α-isoform of gravin have deficits in PKA-dependent long-lasting forms of hippocampal synaptic plasticity including β2-adrenergic receptor-mediated plasticity, and selective impairments of long-term memory storage. Furthermore, both hippocampal β2-adrenergic receptor phosphorylation by PKA, and learning-induced activation of ERK in the CA1 region of the hippocampus are attenuated in mice lacking gravin-α. We conclude that gravin compartmentalizes a significant pool of PKA that regulates learning-induced β2-adrenergic receptor signaling and ERK activation in the hippocampus in vivo, thereby organizing molecular interactions between glutamatergic and noradrenergic signaling pathways for long-lasting synaptic plasticity, and memory storage.
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21
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Gelman IH. Emerging Roles for SSeCKS/Gravin/AKAP12 in the Control of Cell Proliferation, Cancer Malignancy, and Barriergenesis. Genes Cancer 2011; 1:1147-56. [PMID: 21779438 DOI: 10.1177/1947601910392984] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Emerging data suggest that SSeCKS/Gravin/AKAP12 ("AKAP12"), originally identified as an autoantigen in cases of myasthenia gravis, controls multiple biological processes through its ability to scaffold key signaling proteins such as protein kinase (PK) C and A, calmodulin, cyclins, phosphoinositides, "long" β-1,4 galactosyltransferase (GalTase) isoform, Src, as well as the actin cytoskeleton in a spatiotemporal manner. Specialized functions attributed to AKAP12 include the suppression of cancer malignancy, especially aspects of metastatic progression, regulation of blood-brain and blood-retina barrier formation, and resensitization of β2-adrenergic pain receptors. Recent data identify a direct role for AKAP12 in cytokinesis completion, further suggesting a function as a negative regulator of cell senescence. The current review will discuss the emerging knowledge base of AKAP12-related biological roles and how the factors that affect AKAP12 expression or that interact with AKAP12 at the protein level control cancer progression and blood-tissue barrier formation.
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Affiliation(s)
- Irwin H Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY, USA
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22
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Guo LW, Gao L, Rothschild J, Su B, Gelman IH. Control of protein kinase C activity, phorbol ester-induced cytoskeletal remodeling, and cell survival signals by the scaffolding protein SSeCKS/GRAVIN/AKAP12. J Biol Chem 2011; 286:38356-38366. [PMID: 21903576 DOI: 10.1074/jbc.m111.258830] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The product of the SSeCKS/GRAVIN/AKAP12 gene ("SSeCKS") is a major protein kinase (PK) C substrate that exhibits tumor- and metastasis-suppressing activity likely through its ability to scaffold multiple signaling mediators such as PKC, PKA, cyclins, calmodulin, and Src. Although SSeCKS and PKCα bind phosphatidylserine, we demonstrate that phosphatidylserine-independent binding of PKC by SSeCKS is facilitated by two homologous SSeCKS motifs, EG(I/V)(T/S)XWXSFK(K/R)(M/L)VTP(K/R)K(K/R)X(K/R)XXXEXXXE(E/D) (amino acids 592-620 and 741-769). SSeCKS binding to PKCα decreased kinase activity and was dependent on the two PKC-binding motifs. SSeCKS scaffolding of PKC was increased in confluent cell cultures, correlating with significantly increased SSeCKS protein levels and decreased PKCα activity, suggesting a role for SSeCKS in suppressing PKC activation during contact inhibition. SSeCKS-null mouse embryo fibroblasts displayed increased relative basal and phorbol ester (phorbol 12-myristate 13-acetate)-induced PKC activity but were defective in phorbol 12-myristate 13-acetate-induced actin cytoskeletal reorganization and cell shape change; these responses could be rescued by the forced expression of full-length SSeCKS but not by an SSeCKS variant deleted of its PKC-binding domains. Finally, the PKC binding sites in SSeCKS were required to restore cell rounding and/or decreased apoptosis in phorbol ester-treated LNCaP, LNCaP-C4-2, and MAT-LyLu prostate cancer cells. Thus, PKC-mediated remodeling of the actin cytoskeleton is likely regulated by the ability of SSeCKS to control PKC signaling and activity through a direct scaffolding function.
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Affiliation(s)
- Li-Wu Guo
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Lingqiu Gao
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Julian Rothschild
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Bing Su
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Irwin H Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263.
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Streb JW, Long X, Lee TH, Sun Q, Kitchen CM, Georger MA, Slivano OJ, Blaner WS, Carr DW, Gelman IH, Miano JM. Retinoid-induced expression and activity of an immediate early tumor suppressor gene in vascular smooth muscle cells. PLoS One 2011; 6:e18538. [PMID: 21483686 PMCID: PMC3071728 DOI: 10.1371/journal.pone.0018538] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 03/03/2011] [Indexed: 12/19/2022] Open
Abstract
Retinoids are used clinically to treat a number of hyper-proliferative disorders and have been shown in experimental animals to attenuate vascular occlusive diseases, presumably through nuclear receptors bound to retinoic acid response elements (RARE) located in target genes. Here, we show that natural or synthetic retinoids rapidly induce mRNA and protein expression of a specific isoform of A-Kinase Anchoring Protein 12 (AKAP12β) in cultured smooth muscle cells (SMC) as well as the intact vessel wall. Expression kinetics and actinomycin D studies indicate Akap12β is a retinoid-induced, immediate-early gene. Akap12β promoter analyses reveal a conserved RARE mildly induced with atRA in a region that exhibits hyper-acetylation. Immunofluorescence microscopy and protein kinase A (PKA) regulatory subunit overlay assays in SMC suggest a physical association between AKAP12β and PKA following retinoid treatment. Consistent with its designation as a tumor suppressor, inducible expression of AKAP12β attenuates SMC growth in vitro. Further, immunohistochemistry studies establish marked decreases in AKAP12 expression in experimentally-injured vessels of mice as well as atheromatous lesions in humans. Collectively, these results demonstrate a novel role for retinoids in the induction of an AKAP tumor suppressor that blocks vascular SMC growth thus providing new molecular insight into how retiniods may exert their anti-proliferative effects in the injured vessel wall.
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Affiliation(s)
- Jeffrey W. Streb
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Xiaochun Long
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Ting-Hein Lee
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Qiang Sun
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Chad M. Kitchen
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Mary A. Georger
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Orazio J. Slivano
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - William S. Blaner
- Department of Medicine, Columbia University, New York, New York, United States of America
| | - Daniel W. Carr
- Portland Veterans Affairs Medical Center, Portland, Oregon, United States of America
| | - Irwin H. Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Joseph M. Miano
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- * E-mail:
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Goeppert B, Schmezer P, Dutruel C, Oakes C, Renner M, Breinig M, Warth A, Vogel MN, Mittelbronn M, Mehrabi A, Gdynia G, Penzel R, Longerich T, Breuhahn K, Popanda O, Plass C, Schirmacher P, Kern MA. Down-regulation of tumor suppressor A kinase anchor protein 12 in human hepatocarcinogenesis by epigenetic mechanisms. Hepatology 2010; 52:2023-33. [PMID: 20979053 DOI: 10.1002/hep.23939] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 08/17/2010] [Indexed: 12/18/2022]
Abstract
UNLABELLED The A kinase anchor protein 12 (AKAP12) is a central mediator of protein kinase A and protein kinase C signaling. Although AKAP12 has been described to act as a tumor suppressor and its expression is frequently down-regulated in several human malignancies, the underlying molecular mechanisms responsible for the AKAP12 reduction are poorly understood. We therefore analyzed the expression of AKAP12 and its genetic and epigenetic regulatory mechanisms in human hepatocarcinogenesis. Based on tissue microarray analyses (n = 388) and western immunoblotting, we observed a significant reduction of AKAP12 in cirrhotic liver (CL), premalignant lesions (DN), and hepatocellular carcinomas (HCCs) compared to histologically normal liver specimens (NL). Analyses of array comparative genomic hybridization data (aCGH) from human HCCs revealed chromosomal losses of AKAP12 in 36% of cases but suggested additional mechanisms underlying the observed reduction of AKAP12 expression in hepatocarcinogenesis. Quantitative methylation analysis by MassARRAY of NL, CL, DN, and HCC tissues, as well as of various tumorigenic and nontumorigenic liver cell lines revealed specific hypermethylation of the AKAP12α promoter but not of the AKAP12β promoter in HCC specimens and in HCC cell lines. Consequently, restoration experiments performed with 5-aza-2'deoxycytidine drastically increased AKAP12α mRNA levels in a HCC cell line (AKN1) paralleled by AKAP12α promoter demethylation. As hypermethylation is not observed in CL and DN, we investigated microRNA-mediated posttranscriptional regulation as an additional mechanism to explain reduced AKAP12 expression. We found that miR-183 and miR-186 are up-regulated in CL and DN and are able to target AKAP12. CONCLUSION In addition to genetic alterations, epigenetic mechanisms are responsible for the reduction of the tumor suppressor gene AKAP12 in human hepatocarcinogenesis.
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Affiliation(s)
- Benjamin Goeppert
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
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25
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Welch EJ, Jones BW, Scott JD. Networking with AKAPs: context-dependent regulation of anchored enzymes. Mol Interv 2010; 10:86-97. [PMID: 20368369 DOI: 10.1124/mi.10.2.6] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A-Kinase Anchoring Proteins (AKAPs) orchestrate and synchronize cellular events by tethering the cAMP-dependent protein kinase (PKA) and other signaling enzymes to organelles and membranes. The control of kinases and phosphatases that are held in proximity to activators, effectors, and substrates favors the rapid dissemination of information from one cellular location to the next. This article charts the inception of the PKA-anchoring hypothesis, the characterization of AKAPs and their nomenclature, and the physiological roles of context-specific AKAP signaling complexes.
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Affiliation(s)
- Emily J Welch
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA
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Cui Z, Tao T, Cheng C, Yang J, Shen Q, Ji Y, Li X, Liu H, Shen A, Lu X. SSeCKS promote beta-amyloid-induced PC12 cells neurotoxicity by up-regulating tau phosphorylation in Alzheimer's disease. Mol Cell Biochem 2010; 340:257-63. [PMID: 20232114 DOI: 10.1007/s11010-010-0425-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 02/26/2010] [Indexed: 11/25/2022]
Abstract
In Alzheimer's disease, beta-amyloid peptide (Abeta) could induce tau hyperphosphorylation which is the major cause of neuron apoptosis. However, the underlying mechanisms in the process remain unclear. In this study, Abeta-induced apoptosis and tau phosphorylation were investigated in differentiated PC12 cells. This Abeta-induced tau phosphorylation paralleled with the increase of expression and phosphorylation of Src-suppressed protein kinase C substrate (SSeCKS). By knocking down the expression of SSeCKS, Abeta-induced apoptosis and tau hyperphosphorylation in PC12 cells were partially rescued, and were increased further due to the overexpression of SSeCKS in PC12 cells. Also, the cell apoptosis and tau hyperphosphorylation were strongly decreased when the cells were pretreated with the protein kinase C inhibitor, Gö6983. In addition, Abeta-induced tau phosphorylation was also partially decreased due to the overexpression of SSeCKS in PC12cells. In summary, our data indicate that SSeCKS may play a critical role in Abeta-induced PC12 cells apoptosis through its phosphorylation.
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Affiliation(s)
- Zhiming Cui
- Department of Osteology, The Second Affiliated Hospital of Nantong University, Jiangsu Province Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, People's Republic of China
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Mechanisms of protein kinase A anchoring. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 283:235-330. [PMID: 20801421 DOI: 10.1016/s1937-6448(10)83005-9] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The second messenger cyclic adenosine monophosphate (cAMP), which is produced by adenylyl cyclases following stimulation of G-protein-coupled receptors, exerts its effect mainly through the cAMP-dependent serine/threonine protein kinase A (PKA). Due to the ubiquitous nature of the cAMP/PKA system, PKA signaling pathways underlie strict spatial and temporal control to achieve specificity. A-kinase anchoring proteins (AKAPs) bind to the regulatory subunit dimer of the tetrameric PKA holoenzyme and thereby target PKA to defined cellular compartments in the vicinity of its substrates. AKAPs promote the termination of cAMP signals by recruiting phosphodiesterases and protein phosphatases, and the integration of signaling pathways by binding additional signaling proteins. AKAPs are a heterogeneous family of proteins that only display similarity within their PKA-binding domains, amphipathic helixes docking into a hydrophobic groove formed by the PKA regulatory subunit dimer. This review summarizes the current state of information on compartmentalized cAMP/PKA signaling with a major focus on structural aspects, evolution, diversity, and (patho)physiological functions of AKAPs and intends to outline newly emerging directions of the field, such as the elucidation of AKAP mutations and alterations of AKAP expression in human diseases, and the validation of AKAP-dependent protein-protein interactions as new drug targets. In addition, alternative PKA anchoring mechanisms employed by noncanonical AKAPs and PKA catalytic subunit-interacting proteins are illustrated.
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Tao T, Ji Y, Cheng C, Yang H, Liu H, Sun L, Qin Y, Yang J, Wang H, Shen A. Tumor necrosis factor-alpha inhibits Schwann cell proliferation by up-regulating Src-suppressed protein kinase C substrate expression. J Neurochem 2009; 111:647-55. [DOI: 10.1111/j.1471-4159.2009.06346.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rasmussen MH, Wang B, Wabl M, Nielsen AL, Pedersen FS. Activation of alternative Jdp2 promoters and functional protein isoforms in T-cell lymphomas by retroviral insertion mutagenesis. Nucleic Acids Res 2009; 37:4657-71. [PMID: 19502497 PMCID: PMC2724284 DOI: 10.1093/nar/gkp469] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Retroviral insertional mutagenesis has been instrumental for the identification of genes important in cancer development. The molecular mechanisms involved in retroviral-mediated activation of proto-oncogenes influence the distribution of insertions within specific regions during tumorigenesis and hence may point to novel gene structures. From a retroviral tagging screen on tumors of 1767 SL3-3 MLV-infected BALB/c mice, intron 2 of the AP-1 repressor Jdp2 locus was found frequently targeted by proviruses resulting in upregulation of non-canonical RNA subspecies. We identified several promoter regions within 1000 bp upstream of exon 3 that allowed for the production of Jdp2 protein isoforms lacking the histone acetylase inhibitory domain INHAT present in canonical Jdp2. The novel Jdp2 isoforms localized to the nucleus and over-expression in murine fibroblast cells induced cell death similar to canonic Jdp2. When expressed in the context of oncogenic NRAS both full length Jdp2 and the shorter isoforms increased anchorage-independent growth. Our results demonstrate a biological function of Jdp2 lacking the INHAT domain and suggest a post-genomic application for the use of retroviral tagging data in identifying new gene products with a potential role in tumorigenesis.
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Mitra PS, Basu NK, Owens IS. Src supports UDP-glucuronosyltransferase-2B7 detoxification of catechol estrogens associated with breast cancer. Biochem Biophys Res Commun 2009; 382:651-6. [PMID: 19289110 DOI: 10.1016/j.bbrc.2009.03.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/09/2009] [Indexed: 11/30/2022]
Abstract
Mammary gland-distributed and ER-bound UDP-glucuronosyltransferase (UGT)-2B7 metabolizes genotoxic catechol-estrogens (CE) associated with breast cancer initiation. Although UGT2B7 has 3 PKC- and 2 tyrosine kinase (TK)-sites, its inhibition by genistein, herbimycin-A and PP2 with parallel losses in phospho-tyrosine and phospho-Y438-2B7 content indicated it requires tyrosine phosphorylation, unlike required PKC phosphorylation of UGT1A isozymes. 2B7 mutants at PKC-sites had essentially normal activity, while its TK-sites mutants, Y236F- and Y438F-2B7, were essentially inactive. Overexpression of regular or active Src, but not dominant-negative Src, in 2B7-transfected COS-1 cells increased 2B7 activity and phospho-Y438-2B7 by 50%. Co-localization of 2B7 and regular SrcTK in COS-1 cells that was dissociated by pretreatment with Src-specific PP2-inhibitor provided strong evidence Src supports 2B7 activity. Consistent with these findings, evidence indicates an appropriate set of ER proteins with Src-homology binding-domains, including 2B7 and well-known multi-functional Src-engaged AKAP12 scaffold, supports Src-dependent phosphorylation of CE-metabolizing 2B7 enabling it to function as a tumor suppressor.
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Affiliation(s)
- Partha S Mitra
- Section on Genetic Disorders of Drug Metabolism, Program on Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892-1830, USA
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Liu H, Huang X, Wang H, Shen A, Cheng C. Dexamethasone inhibits proliferation and stimulates SSeCKS expression in C6 rat glioma cell line. Brain Res 2009; 1265:1-12. [PMID: 19368818 DOI: 10.1016/j.brainres.2009.01.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 01/13/2009] [Accepted: 01/22/2009] [Indexed: 12/28/2022]
Abstract
Although there is ample evidence that dexamethasone (DEX) has an antiproliferative effect on C6 glioma cells, the molecular mechanism remains elusive. Src suppressed C kinase substrates (SSeCKS), as a member of PKC substrates, have been implicated to be a negative regulator of cell proliferation. In this study, we provided novel evidence that DEX induced the expression of SSeCKS mRNA and protein in a time- and dose-dependent manner, and translocation of SSeCKS from the cytosol to the membrane. The glucocorticoid receptor antagonist, RU486, significantly decreased DEX-induced SSeCKS expression, inhibited SSeCKS translocation and actin cytoskeleton reorganization after DEX challenge. Knock-down of SSeCKS expression by RNA interference inhibited DEX-induced actin cytoskeleton reorganization and reversed DEX-induced growth arrest. We also presented the novel observation that knock-down of SSeCKS expression elevated the expression of cyclin D1 and the phosphorylation of extracellular signal-regulated Kinase 1/2, indicating that SSeCKS is involved in the regulation of cell cycle related proteins and is essential for DEX induced growth arrest.
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Affiliation(s)
- Haiou Liu
- Jiangsu Province Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
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Yan X, Walkiewicz M, Carlson J, Leiphon L, Grove B. Gravin dynamics regulates the subcellular distribution of PKA. Exp Cell Res 2009; 315:1247-59. [PMID: 19210988 DOI: 10.1016/j.yexcr.2008.12.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 12/24/2008] [Accepted: 12/27/2008] [Indexed: 11/18/2022]
Abstract
Gravin, a multivalent A-kinase anchoring protein (AKAP), localizes to the cell periphery in several cell types and is postulated to target PKA and other binding partners to the plasma membrane. An N-terminal myristoylation sequence and three regions rich in basic amino acids are proposed to mediate this localization. Reports indicating that phorbol ester affects the distribution of SSeCKS, the rat orthologue of gravin, further suggest that PKC may also regulate the subcellular distribution of gravin, which in turn may affect PKA distribution. In this study, quantitative confocal microscopy of cells expressing full-length and mutant gravin-EGFP constructs lacking the proposed targeting domains revealed that either the N-myristoylation site or the polybasic regions were sufficient to target gravin to the cell periphery. Moreover, phorbol ester treatment induced redistribution of gravin-EGFP from the cell periphery to a juxtanuclear vesicular compartment, but this required the presence of the N-myristoylation site. Confocal microscopy further revealed that not only did gravin-EGFP target a PKA RII-ECFP construct to the cell periphery, but PKC activation resulted in redistribution of the gravin and PKA constructs to the same subcellular site. It is postulated that this dynamic response by gravin to PKC activity may mediate PKC dependent control of PKA activity.
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Affiliation(s)
- Xiaohong Yan
- Department of Anatomy and Cell Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202-9037, USA
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Akakura S, Huang C, Nelson PJ, Foster B, Gelman IH. Loss of the SSeCKS/Gravin/AKAP12 gene results in prostatic hyperplasia. Cancer Res 2008; 68:5096-103. [PMID: 18593908 DOI: 10.1158/0008-5472.can-07-5619] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
SSeCKS/Gravin/AKAP12 (SSeCKS) is a kinase scaffolding protein that encodes metastasis-suppressor activity through the suppression of Src-mediated oncogenic signaling and vascular endothelial growth factor expression. SSeCKS expression is down-regulated in Src- and Ras-transformed fibroblasts, in human cancer cell lines and in several types of human cancer, including prostate. Normal human and mouse prostates express abundant SSeCKS in secretory epithelial cells and, to a lesser extent, in the surrounding mesenchyme. Here, we show that the loss of SSeCKS results in prostatic hyperplasia in the anterior and ventral lobes as well as increased levels of apoptosis throughout the prostate. Dysplastic foci were observed less frequently but were associated with the loss of E-cadherin staining and the loss of high molecular weight cytokeratin-positive basal epithelial cells. SSeCKS-null prostate tissues expressed significantly higher relative levels of AKT(poS473) compared with wild-type controls, suggesting that SSeCKS attenuates phosphatidylinositol-3-OH kinase signaling. The data suggest that SSeCKS-null mice have increased susceptibility for oncogenic transformation in the prostate.
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Affiliation(s)
- Shin Akakura
- Department of Cancer Genetics, Therapeutics Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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Bu Y, Gelman IH. v-Src-mediated Down-regulation of SSeCKS Metastasis Suppressor Gene Promoter by the Recruitment of HDAC1 into a USF1-Sp1-Sp3 Complex. J Biol Chem 2007; 282:26725-26739. [PMID: 17626016 DOI: 10.1074/jbc.m702885200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
SSeCKS (Src-suppressed C kinase substrate), also called gravin/AKAP12, is a large scaffolding protein with metastasis suppressor activity. Two major isoforms of SSeCKS are expressed in most cell and tissue types under the control of two independent promoters, designated alpha and beta, separated by 68 kb. SSeCKS transcript and protein levels are severely decreased in Src- and Ras-transformed fibroblasts and in many epithelial tumors. By dissecting its promoters with progressive deletion analysis, we identified the sequence between -106 and -49 in the alpha proximal promoter as the minimal v-Src-responsive element, which contains E- and GC-boxes bound by USF1 and Sp1/Sp3, respectively. Both E- and GC-boxes are crucial for v-Src-responsive and basal promoter activities. v-Src does not alter USF1 binding levels at the E-box, but it increases Sp1/Sp3 binding to the GC-box despite no change in their cellular protein abundance. SSeCKS alpha and beta transcript levels in v-Src/3T3 cells can be restored by treatment with the histone deacetylase inhibitor, trichostatin A, but not with the DNA demethylation agent, 5-azacytidine. Chromatin changes are found only on the alpha promoter even though the beta proximal promoter contains a similar E- and GC-box arrangement. Recruitment of HDAC1 is necessary and sufficient to cause repression of alpha proximal promoter activity, and the addition of Sp1 and/or Sp3 potentiates the repression. Our data suggest that suppression of the beta promoter is facilitated by Src-induced changes in the alpha promoter chromatinization mediated by a USF1-Sp1-Sp3 complex.
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Affiliation(s)
- Yahao Bu
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Irwin H Gelman
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263.
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Liu GB, Jiang YF, Yan H, Zhao KN. Computational analysis of base composition pattern and promoter elements in the putative promoter regions in relation to expression profiles of 682 human genes on chromosome 22. ACTA ACUST UNITED AC 2007; 17:270-81. [PMID: 17312946 DOI: 10.1080/10425170600886136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Abstract The base composition pattern (BCP) in the putative promoter region (PPRs) up to 5 Kb lengths of 682 human genes on Chromosome 22 (Chr22) was examined. Two-dimensional (2D) and three-dimensional (3D) functions were designed to delineate the DNA base composition, with four major patterns identified. It is found that 17.6% genes include TATA box, 28.0% GC box, 18.9% CAAT box and 38.4% CpG islands, and approximately 10% genes have one of four putative initiator (Inr) motifs. The occurrence of the promoter elements is tightly associated with the base composition features in the promoter regions, and the associations of the base composition features with occurrence of the promoter elements in the promoter regions mediate tissue-wide expression of the genes in human. The occurrence of two or more promoter elements in the promoter regions is required for the medium- and wide-range expression profiles of the human genes on Chr22. Thus, the reported data shed light on the characteristics of the PPRs of the human genes on Chr22, which may improve our understanding of regulatory roles of the PPRs with occurrence of the promoter elements in gene expression.
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Affiliation(s)
- Guang Bin Liu
- Department of Biological and Physical Sciences, Faculty of Science, Centre for Systems Biology, The University of Southern Queensland, Toowoomba, Qld 4350, Australia.
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Jo U, Whang YM, Kim HK, Kim YH. AKAP12alpha is associated with promoter methylation in lung cancer. Cancer Res Treat 2006; 38:144-51. [PMID: 19771275 DOI: 10.4143/crt.2006.38.3.144] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2006] [Accepted: 06/30/2006] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Promoter methylation is an important mechanism for silencing tumor-suppressor genes in cancer and it is a promising tool for the development of molecular biomarkers. The purpose of the present study was to investigate whether inactivation of the A Kinase Anchoring Protein 12 (AKAP12) gene is assoCiated with promoter methylation in lung cancer. MATERIALS AND METHODS The AKAP12 expression was examined by reverse transcription-polymerase chain reaction (RT-PCR) in ten lung cancer cell lines. The methylation status of the AKAP12alpha promoter was analyzed by performing bisulfite sequencing analysis in ten lung cancer cell lines, twenty four lung tissues and matched normal tissues. RESULTS The AKAP12alpha expression was reduced in 6 of 10 (60%) lung cancer cell lines, whereas the AKAP12beta expression was absent in 1 of 10 (10%) lung cancer cell lines. The AKAP12alpha expression was restored after treatment with the demethylating agent 5-aza-2'-deoxycytidine in three lung cancer cell lines. Methylation of CpG island 1 in the AKAP12alpha promoter was detected in 30% of the lung cancer cell lines, whereas methylation of CpG island 2 in the AKAP12alpha promoter was observed in the immortalized bronchial cell line and in all the lung cancer cell lines. In lung tumors, the CpG island 1 in the AKAP12alpha promoter was infrequently methylated. However, CpG island 2 in the AKAP12alpha promoter was highly methylated in lung tumors compared with the surrounding normal tissues, and this was statistically significant (p=0.0001). CONCLUSION Our results suggest that inactivation of the AKAP12alpha expression is assoCiated with DNA methylation of the promoter region in lung cancer, and that AKAP12alpha may play an important role in lung cancer carcinogenesis.
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Affiliation(s)
- Ukhyun Jo
- Department of Internal Medicine and Brain Korea 21 Project for Biomedical Science, Korea University College of Medicine, Seoul, Korea
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Sun Q, Chen G, Streb JW, Long X, Yang Y, Stoeckert CJ, Miano JM. Defining the mammalian CArGome. Genes Dev 2006; 16:197-207. [PMID: 16365378 PMCID: PMC1361715 DOI: 10.1101/gr.4108706] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Accepted: 11/01/2005] [Indexed: 11/24/2022]
Abstract
Serum response factor (SRF) binds a 1216-fold degenerate cis element known as the CArG box. CArG boxes are found primarily in muscle- and growth-factor-associated genes although the full spectrum of functional CArG elements in the genome (the CArGome) has yet to be defined. Here we describe a genome-wide screen to further define the functional mammalian CArGome. A computational approach involving comparative genomic analyses of human and mouse orthologous genes uncovered >100 hypothetical SRF-dependent genes, including 10 previously identified SRF targets, harboring a conserved CArG element within 4000 bp of the annotated transcription start site (TSS). We PCR-cloned 89 hypothetical SRF targets and subjected each of them to at least two of several validations including luciferase reporter, gel shift, chromatin immunoprecipitation, and mRNA expression following RNAi knockdown of SRF; 60/89 (67%) of the targets were validated. Interestingly, 26 of the validated SRF target genes encode for cytoskeletal/contractile or adhesion proteins. RNAi knockdown of SRF diminishes expression of several SRF-dependent cytoskeletal genes and elicits an attending perturbation in the cytoarchitecture of both human and rodent cells. These data illustrate the power of integrating existing algorithms to interrogate the genome in a relatively unbiased fashion for cis-regulatory element discovery. In this manner, we have further expanded the mammalian CArGome with the discovery of an array of cyto-contractile genes that coordinate normal cytoskeletal homeostasis. We suggest one function of SRF is that of an ancient master regulator of the actin cytoskeleton.
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Affiliation(s)
- Qiang Sun
- Cardiovascular Research Institute, University of Rochester School of Medicine, Rochester, NY 14642, USA
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38
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Ding B, Abe JI, Wei H, Xu H, Che W, Aizawa T, Liu W, Molina CA, Sadoshima J, Blaxall BC, Berk BC, Yan C. A positive feedback loop of phosphodiesterase 3 (PDE3) and inducible cAMP early repressor (ICER) leads to cardiomyocyte apoptosis. Proc Natl Acad Sci U S A 2005; 102:14771-6. [PMID: 16186489 PMCID: PMC1253575 DOI: 10.1073/pnas.0506489102] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
cAMP plays crucial roles in cardiac remodeling and the progression of heart failure. Recently, we found that expression of cAMP hydrolyzing phosphodiesterase 3A (PDE3A) was significantly reduced in human failing hearts, accompanied by up-regulation of inducible cAMP early repressor (ICER) expression. Angiotensin II (Ang II) and the beta-adrenergic receptor agonist isoproterenol (ISO) also induced persistent PDE3A down-regulation and concomitant ICER up-regulation in vitro, which is important in Ang II- and ISO-induced cardiomyocyte apoptosis. We hypothesized that interactions between PDE3A and ICER may constitute an autoregulatory positive feedback loop (PDE3A-ICER feedback loop), and this loop would cause persistent PDE3A down-regulation and ICER up-regulation. Here, we demonstrate that ICER induction repressed PDE3A gene transcription. PDE3A down-regulation activated cAMP/PKA signaling, leading to ICER up-regulation via PKA-dependent stabilization of ICER. With respect to Ang II, the initiation of the PDE3A-ICER feedback loop depends on activation of Ang II type 1 receptor (AT1R), classical PKC(s), and CREB (cAMP response element binding protein). We further show that the PDE3A-ICER feedback loop is essential for Ang II-induced cardiomyocyte apoptosis. ISO and PDE3 inhibitors also induced the PDE3A-ICER feedback loop and subsequent cardiomyocyte apoptosis, highlighting the importance of this PDE3A-ICER feedback loop and cAMP signaling in cardiomyocyte apoptosis. Our findings may provide a therapeutic paradigm to prevent cardiomyocyte apoptosis and the progression of heart failure by inhibiting the PDE3A-ICER feedback loop.
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Affiliation(s)
- Bo Ding
- Cardiovascular Research Institute, Department of Pathology, University of Rochester, Rochester, NY 14642, USA
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Streb JW, Miano JM. Cross-species sequence analysis reveals multiple charged residue-rich domains that regulate nuclear/cytoplasmic partitioning and membrane localization of a kinase anchoring protein 12 (SSeCKS/Gravin). J Biol Chem 2005; 280:28007-14. [PMID: 15923193 DOI: 10.1074/jbc.m414017200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A kinase anchoring proteins (AKAPs) assemble and compartmentalize multiprotein signaling complexes at discrete subcellular locales and thus confer specificity to transduction cascades using ubiquitous signaling enzymes, such as protein kinase A. Intrinsic targeting domains in each AKAP determine the subcellular localization of these complexes and, along with protein-protein interaction domains, form the core of AKAP function. As a foundational step toward elucidating the relationship between location and function, we have used cross-species sequence analysis and deletion mapping to facilitate the identification of the targeting determinants of AKAP12 (also known as SSeCKS or Gravin). Three charged residue-rich regions were identified that regulate two aspects of AKAP12 localization, nuclear/cytoplasmic partitioning and perinuclear/cell periphery targeting. Using deletion mapping and green fluorescent protein chimeras, we uncovered a heretofore unrecognized nuclear localization potential. Five nuclear localization signals, including a novel class of this type of signal termed X2-NLS, are found in the central region of AKAP12 and are important for nuclear targeting. However, this nuclear localization is suppressed by the negatively charged C terminus that mediates nuclear exclusion. In this condition, the distribution of AKAP12 is regulated by an N-terminal targeting domain that simultaneously directs perinuclear and peripheral AKAP12 localization. Three basic residue-rich regions in the N-terminal targeting region have similarity to the MARCKS proteins and were found to control AKAP12 localization to ganglioside-rich regions at the cell periphery. Our data suggest that AKAP12 localization is regulated by a hierarchy of targeting domains and that the localization of AKAP12-assembled signaling complexes may be dynamically regulated.
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Affiliation(s)
- Jeffrey W Streb
- Center for Cardiovascular Research in the Aab Institute of Biomedical Sciences, University of Rochester School of Medicine, Rochester, New York 14642, USA
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40
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Abstract
We recently identified three AKAP12 isoforms that are differentially regulated by distinct promoters. During a screen to identify molecular determinants distinguishing the activities of these promoters, we found a potential binding site for the serum response factor (SRF) in the promoter of the ubiquitously expressed AKAP12alpha isoform. SRF is an evolutionarily conserved transcription factor that governs disparate programs of gene expression linked to cellular growth and differentiation. Using a combination of reporter assays and RNA interference, we demonstrate that SRF is required for AKAP12alpha expression. SRF regulates the activity of the AKAP12alpha promoter through two conserved CArG boxes that bind SRF with different affinities. Unlike other SRF-dependent genes, AKAP12alpha is not regulated by growth or differentiation stimuli. Molecular analysis of the AKAP12alpha SRF-binding sites, or CArG boxes, indicates that sequences flanking these sites are the determinants of sensitivity to SRF-activating signals. Specifically, the AKAP12alpha CArG boxes are shielded from growth stimulation by the absence of a binding site for Ets transcription factors. Similarly, sensitivity to the differentiation-associated co-factor, myocardin, was also determined by responsive flanking sequence; however, unlike growth stimuli, sensitivity to myocardin was found to also be dependent on a consensus CArG box. Collectively, our data demonstrate that AKAP12alpha belongs to a novel class of atypical SRF-dependent target genes. Furthermore, we provide new insight into the role of flanking sequences in determining sensitivity to SRF-myocardin activity.
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Affiliation(s)
- Jeffrey W Streb
- Center for Cardiovascular Research in the Aab Institute of Biomedical Sciences, University of Rochester School of Medicine, Rochester, New York 14642, USA
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