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Ran Q, Li A, Tan Y, Zhang Y, Zhang Y, Chen H. Action and therapeutic targets of myosin light chain kinase, an important cardiovascular signaling mechanism. Pharmacol Res 2024; 206:107276. [PMID: 38944220 DOI: 10.1016/j.phrs.2024.107276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Accepted: 06/19/2024] [Indexed: 07/01/2024]
Abstract
The global incidence of cardiac diseases is increasing, imposing a substantial socioeconomic burden on healthcare systems. The pathogenesis of cardiovascular disease is complex and not fully understood, and the physiological function of the heart is inextricably linked to well-regulated cardiac muscle movement. Myosin light chain kinase (MLCK) is essential for myocardial contraction and diastole, cardiac electrophysiological homeostasis, vasoconstriction of vascular nerves and blood pressure regulation. In this sense, MLCK appears to be an attractive therapeutic target for cardiac diseases. MLCK participates in myocardial cell movement and migration through diverse pathways, including regulation of calcium homeostasis, activation of myosin light chain phosphorylation, and stimulation of vascular smooth muscle cell contraction or relaxation. Recently, phosphorylation of myosin light chains has been shown to be closely associated with the activation of myocardial exercise signaling, and MLCK mediates systolic and diastolic functions of the heart through the interaction of myosin thick filaments and actin thin filaments. It works by upholding the integrity of the cytoskeleton, modifying the conformation of the myosin head, and modulating innervation. MLCK governs vasoconstriction and diastolic function and is associated with the activation of adrenergic and sympathetic nervous systems, extracellular transport, endothelial permeability, and the regulation of nitric oxide and angiotensin II. Additionally, MLCK plays a crucial role in the process of cardiac aging. Multiple natural products/phytochemicals and chemical compounds, such as quercetin, cyclosporin, and ML-7 hydrochloride, have been shown to regulate cardiomyocyte MLCK. The MLCK-modifying capacity of these compounds should be considered in designing novel therapeutic agents. This review summarizes the mechanism of action of MLCK in the cardiovascular system and the therapeutic potential of reported chemical compounds in cardiac diseases by modifying MLCK processes.
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Affiliation(s)
- Qingzhi Ran
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China
| | - Aoshuang Li
- Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine, Beijing 100053, China
| | - Yuqing Tan
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China
| | - Yue Zhang
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China.
| | - Yongkang Zhang
- Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200082, China.
| | - Hengwen Chen
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China.
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2
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Orsini EM, Roychowdhury S, Gangadhariah M, Cross E, Abraham S, Reinhardt A, Grund ME, Zhou JY, Stuehr O, Pant B, Olman MA, Vachharajani V, Scheraga RG. TRPV4 Regulates the Macrophage Metabolic Response to Limit Sepsis-induced Lung Injury. Am J Respir Cell Mol Biol 2024; 70:457-467. [PMID: 38346220 PMCID: PMC11160412 DOI: 10.1165/rcmb.2023-0456oc] [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] [Received: 12/22/2023] [Accepted: 02/12/2024] [Indexed: 02/21/2024] Open
Abstract
Sepsis is a systemic inflammatory response that requires effective macrophage metabolic functions to resolve ongoing inflammation. Previous work showed that the mechanosensitive cation channel, transient receptor potential vanilloid 4 (TRPV4), mediates macrophage phagocytosis and cytokine production in response to lung infection. Here, we show that TRPV4 regulates glycolysis in a stiffness-dependent manner by augmenting macrophage glucose uptake by GLUT1. In addition, TRPV4 is required for LPS-induced phagolysosome maturation in a GLUT1-dependent manner. In a cecal slurry mouse model of sepsis, TRPV4 regulates sepsis-induced glycolysis as measured by BAL fluid (BALF) lactate and sepsis-induced lung injury as measured by BALF total protein and lung compliance. TRPV4 is necessary for bacterial clearance in the peritoneum to limit sepsis-induced lung injury. It is interesting that BALF lactate is increased in patients with sepsis compared with healthy control participants, supporting the relevance of lung cell glycolysis to human sepsis. These data show that macrophage TRPV4 is required for glucose uptake through GLUT1 for effective phagolysosome maturation to limit sepsis-induced lung injury. Our work presents TRPV4 as a potential target to protect the lung from injury in sepsis.
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Affiliation(s)
- Erica M. Orsini
- Department of Pulmonary and Critical Care, Integrated Hospital Care Institute, and
| | - Sanjoy Roychowdhury
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Mahesha Gangadhariah
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Emily Cross
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Susamma Abraham
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Amanda Reinhardt
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Megan E. Grund
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Julie Y. Zhou
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Olivia Stuehr
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Bishnu Pant
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Mitchell A. Olman
- Department of Pulmonary and Critical Care, Integrated Hospital Care Institute, and
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Vidula Vachharajani
- Department of Pulmonary and Critical Care, Integrated Hospital Care Institute, and
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Rachel G. Scheraga
- Department of Pulmonary and Critical Care, Integrated Hospital Care Institute, and
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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Perez-Garcia J, Pino-Yanes M, Plender EG, Everman JL, Eng C, Jackson ND, Moore CM, Beckman KB, Medina V, Sharma S, Winnica DE, Holguin F, Rodríguez-Santana J, Villar J, Ziv E, Seibold MA, Burchard EG. Epigenomic response to albuterol treatment in asthma-relevant airway epithelial cells. Clin Epigenetics 2023; 15:156. [PMID: 37784136 PMCID: PMC10546710 DOI: 10.1186/s13148-023-01571-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 09/25/2023] [Indexed: 10/04/2023] Open
Abstract
BACKGROUND Albuterol is the first-line asthma medication used in diverse populations. Although DNA methylation (DNAm) is an epigenetic mechanism involved in asthma and bronchodilator drug response (BDR), no study has assessed whether albuterol could induce changes in the airway epithelial methylome. We aimed to characterize albuterol-induced DNAm changes in airway epithelial cells, and assess potential functional consequences and the influence of genetic variation and asthma-related clinical variables. RESULTS We followed a discovery and validation study design to characterize albuterol-induced DNAm changes in paired airway epithelial cultures stimulated in vitro with albuterol. In the discovery phase, an epigenome-wide association study using paired nasal epithelial cultures from Puerto Rican children (n = 97) identified 22 CpGs genome-wide associated with repeated-use albuterol treatment (p < 9 × 10-8). Albuterol predominantly induced a hypomethylation effect on CpGs captured by the EPIC array across the genome (probability of hypomethylation: 76%, p value = 3.3 × 10-5). DNAm changes on the CpGs cg23032799 (CREB3L1), cg00483640 (MYLK4-LINC01600), and cg05673431 (KSR1) were validated in nasal epithelia from 10 independent donors (false discovery rate [FDR] < 0.05). The effect on the CpG cg23032799 (CREB3L1) was cross-tissue validated in bronchial epithelial cells at nominal level (p = 0.030). DNAm changes in these three CpGs were shown to be influenced by three independent genetic variants (FDR < 0.05). In silico analyses showed these polymorphisms regulated gene expression of nearby genes in lungs and/or fibroblasts including KSR1 and LINC01600 (6.30 × 10-14 ≤ p ≤ 6.60 × 10-5). Additionally, hypomethylation at the CpGs cg10290200 (FLNC) and cg05673431 (KSR1) was associated with increased gene expression of the genes where they are located (FDR < 0.05). Furthermore, while the epigenetic effect of albuterol was independent of the asthma status, severity, and use of medication, BDR was nominally associated with the effect on the CpG cg23032799 (CREB3L1) (p = 0.004). Gene-set enrichment analyses revealed that epigenomic modifications of albuterol could participate in asthma-relevant processes (e.g., IL-2, TNF-α, and NF-κB signaling pathways). Finally, nine differentially methylated regions were associated with albuterol treatment, including CREB3L1, MYLK4, and KSR1 (adjusted p value < 0.05). CONCLUSIONS This study revealed evidence of epigenetic modifications induced by albuterol in the mucociliary airway epithelium. The epigenomic response induced by albuterol might have potential clinical implications by affecting biological pathways relevant to asthma.
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Grants
- R01 ES015794 NIEHS NIH HHS
- R01 HL120393 NHLBI NIH HHS
- R01ES015794, R21ES24844 NIEHS NIH HHS
- UM1 HG008901 NHGRI NIH HHS
- R01MD010443, R56MD013312 NIMHD NIH HHS
- R01 HL135156 NHLBI NIH HHS
- R01 HL128439 NHLBI NIH HHS
- R01 HL117004 NHLBI NIH HHS
- R21 ES024844 NIEHS NIH HHS
- R01 HL117626 NHLBI NIH HHS
- R56 MD013312 NIMHD NIH HHS
- R01 MD010443 NIMHD NIH HHS
- R01 HL155024 NHLBI NIH HHS
- R01HL155024-01, HHSN268201600032I, 3R01HL-117626-02S1, HHSN268201800002I, 3R01HL117004-02S3, 3R01HL-120393-02S1, R01HL117004, R01HL128439, R01HL135156, X01HL134589 NHLBI NIH HHS
- HHSN268201600032C NHLBI NIH HHS
- U24 HG008956 NHGRI NIH HHS
- Ministerio de Universidades
- Ministerio de Ciencia e Innovación
- Instituto de Salud Carlos III
- National Heart, Lung, and Blood Institute
- National Human Genome Research Institute
- National Institute of Environmental Health Sciences
- National Institute on Minority Health and Health Disparities
- The Centers for Common Disease Genomics of the Genome Sequencing Program
- Tobacco-Related Disease Research Program
- Sandler Family Foundation
- American Asthma Foundation
- Amos Medical Faculty Development Program from the Robert Wood Johnson Foundation
- Harry Wm. and Diana V. Hind Distinguished Professor in Pharmaceutical Sciences II
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Affiliation(s)
- Javier Perez-Garcia
- Genomics and Health Group, Department of Biochemistry, Microbiology, Cell Biology, and Genetics, Universidad de La Laguna (ULL), La Laguna, Tenerife, Canary Islands, Spain.
| | - Maria Pino-Yanes
- Genomics and Health Group, Department of Biochemistry, Microbiology, Cell Biology, and Genetics, Universidad de La Laguna (ULL), La Laguna, Tenerife, Canary Islands, Spain.
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.
- Instituto de Tecnologías Biomédicas (ITB), Universidad de La Laguna (ULL), La Laguna, Spain.
| | - Elizabeth G Plender
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
| | - Jamie L Everman
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
| | - Celeste Eng
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Nathan D Jackson
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
| | - Camille M Moore
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
- Department of Biomedical Research, National Jewish Health, Denver, CO, USA
- Department of Biostatistics and Informatics, University of Colorado, Denver, CO, USA
| | - Kenneth B Beckman
- University of Minnesota Genomics Center (UMNGC), Minneapolis, MN, USA
| | | | - Sunita Sharma
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Daniel Efrain Winnica
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Fernando Holguin
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | | | - Jesús Villar
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
- Multidisciplinary Organ Dysfunction Evaluation Research Network (MODERN), Research Unit, Hospital Universitario Dr. Negrín, Las Palmas de Gran Canaria, Spain
- Li Ka Shing Knowledge Institute at the St. Michael's Hospital, Toronto, ON, Canada
| | - Elad Ziv
- Institute for Human Genetics, University of California San Francisco (UCSF), San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Max A Seibold
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
- Department of Pediatrics, National Jewish Health, Denver, CO, USA
| | - Esteban G Burchard
- Department of Medicine, University of California San Francisco (UCSF), San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco (UCSF), San Francisco, CA, USA
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4
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Hong SH, Jang EB, Hwang HJ, Park SY, Moon HS, Yoon YE. Effect of α1D-adrenoceptor blocker for the reduction of ureteral contractions. Investig Clin Urol 2023; 64:82-90. [PMID: 36629069 PMCID: PMC9834562 DOI: 10.4111/icu.20220254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 11/01/2022] [Accepted: 11/21/2022] [Indexed: 12/24/2022] Open
Abstract
PURPOSE Urolithiasis is a common urinary tract disease with growing prevalence. Alpha1-adrenoceptors (α1-ARs) are abundant in ureteral smooth muscle, distributed with different α1-AR subtypes. α1D-AR is the most widely distributed in the ureter. However, the effect of α1D-AR blockade on ureteric contraction remains unknown. MATERIALS AND METHODS We dissected smooth muscle tissues (3 mm×3 mm) from the rat bladder and human ureter, tied silk strips on both tissue ends, and measured contraction in an organ bath chamber. Contraction activity in ureteral smooth muscle cells (USMCs) was immunocytochemically examined using primary rat and human USMC cultures. RESULTS Using the organ bath system, we determined the inhibitory effects of silodosin, tamsulosin, and naftopidil. Naftopidil significantly decreased contractility of rat bladder tissue; similar results were observed in human ureteral tissue. To confirm ex vivo experimental results in vitro , we examined the phosphorylation of myosin light chain (MLC), a marker of contractility, in a primary human USMC culture. The examined drugs decreased phospho-MLC levels in human USMCs; however, naftopidil profoundly increased MLC dephosphorylation. CONCLUSIONS We studied the effects of naftopidil, an α1D-AR inhibitor, on the ureter. Compared with alpha-blockers, naftopidil significantly relaxed ureteral smooth muscle. Therefore, naftopidil could be an effective therapy for patients with ureteral stones.
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Affiliation(s)
- Seong Hwi Hong
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea
| | - Eun Bi Jang
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea.,Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Korea
| | - Hyun Ji Hwang
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea.,Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul, Korea
| | - Sung Yul Park
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea
| | - Hong Sang Moon
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea
| | - Young Eun Yoon
- Department of Urology, Hanyang University College of Medicine, Seoul, Korea.,Department of Medical and Digital Engineering, Hanyang University Graduate School, Seoul, Korea
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5
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Identification of AGR2 Gene-Specific Expression Patterns Associated with Epithelial-Mesenchymal Transition. Int J Mol Sci 2022; 23:ijms231810845. [PMID: 36142758 PMCID: PMC9504245 DOI: 10.3390/ijms231810845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/01/2022] [Accepted: 09/13/2022] [Indexed: 11/28/2022] Open
Abstract
The TGF-β signaling pathway is involved in numerous cellular processes, and its deregulation may result in cancer development. One of the key processes in tumor progression and metastasis is epithelial to mesenchymal transition (EMT), in which TGF-β signaling plays important roles. Recently, AGR2 was identified as a crucial component of the cellular machinery responsible for maintaining the epithelial phenotype, thereby interfering with the induction of mesenchymal phenotype cells by TGF-β effects in cancer. Here, we performed transcriptomic profiling of A549 lung cancer cells with CRISPR-Cas9 mediated AGR2 knockout with and without TGF-β treatment. We identified significant changes in transcripts associated with focal adhesion and eicosanoid production, in particular arachidonic acid metabolism. Changes in transcripts associated with the focal adhesion pathway were validated by RT-qPCR of COL4A1, COL4A2, FLNA, VAV3, VEGFA, and VINC mRNAs. In addition, immunofluorescence showed the formation of stress fibers and vinculin foci in cells without AGR2 and in response to TGF-β treatment, with synergistic effects observed. These findings imply that both AGR2 downregulation and TGF-β have a role in focal adhesion formation and cancer cell migration and invasion. Transcripts associated with arachidonic acid metabolism were downregulated after both AGR2 knockout and TGF-β treatment and were validated by RT-qPCR of GPX2, PTGS2, and PLA2G4A. Since PGE2 is a product of arachidonic acid metabolism, its lowered concentration in media from AGR2-knockout cells was confirmed by ELISA. Together, our results demonstrate that AGR2 downregulation and TGF-β have an essential role in focal adhesion formation; moreover, we have identified AGR2 as an important component of the arachidonic acid metabolic pathway.
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Nejmanová I, Vitverová B, Eissazadeh S, Tripská K, Igreja Sa IC, Hyšpler R, Němečkova I, Pericacho M, Nachtigal P. High Soluble Endoglin Levels Affect Aortic Vascular Function during Mice Aging. J Cardiovasc Dev Dis 2021; 8:jcdd8120173. [PMID: 34940528 PMCID: PMC8703792 DOI: 10.3390/jcdd8120173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/22/2021] [Accepted: 12/01/2021] [Indexed: 11/21/2022] Open
Abstract
Endoglin is a 180 kDa transmembrane glycoprotein that was demonstrated to be present in two different endoglin forms, namely membrane endoglin (Eng) and soluble endoglin (sEng). Increased sEng levels in the circulation have been detected in atherosclerosis, arterial hypertension, and type II diabetes mellitus. Moreover, sEng was shown to aggravate endothelial dysfunction when combined with a high-fat diet, suggesting it might be a risk factor for the development of endothelial dysfunction in combination with other risk factors. Therefore, this study hypothesized that high sEng levels exposure for 12 months combined with aging (an essential risk factor of atherosclerosis development) would aggravate vascular function in mouse aorta. Male transgenic mice with high levels of human sEng in plasma (Sol-Eng+) and their age-matched male transgenic littermates that do not develop high soluble endoglin (Control) on a chow diet were used. The aging process was initiated to contribute to endothelial dysfunction/atherosclerosis development, and it lasted 12 months. Wire myograph analysis showed impairment contractility in the Sol-Eng+ group when compared to the control group after KCl and PGF2α administration. Endothelium-dependent responsiveness to Ach was not significantly different between these groups. Western blot analysis revealed significantly decreased protein expression of Eng, p-eNOS, and ID1 expression in the Sol-Eng+ group compared to the control group suggesting reduced Eng signaling. In conclusion, we demonstrated for the first time that long-term exposure to high levels of sEng during aging results in alteration of vasoconstriction properties of the aorta, reduced eNOS phosphorylation, decreased Eng expression, and altered Eng signaling. These findings suggest that sEng can be considered a risk factor for the development of vascular dysfunction during aging and a potential therapeutical target for pharmacological intervention.
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Affiliation(s)
- Iveta Nejmanová
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
| | - Barbora Vitverová
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
| | - Samira Eissazadeh
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
| | - Katarina Tripská
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
| | - Ivone Cristina Igreja Sa
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
| | - Radomír Hyšpler
- Centrum for Research and Development, University Hospital, 500 05 Hradec Kralove, Czech Republic;
| | - Ivana Němečkova
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
| | - Miguel Pericacho
- Renal and Cardiovascular Research Unit, Department of Physiology and Pharmacology, Biomedical Research Institute of Salamanca (IBSAL), University of Salamanca, 37007 Salamanca, Spain;
| | - Petr Nachtigal
- Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic; (I.N.); (B.V.); (S.E.); (K.T.); (I.C.I.S.); (I.N.)
- Correspondence:
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7
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Yang M, Zhang T, Zhang Y, Ma X, Han J, Zeng K, Jiang Y, Wang Z, Wang Z, Xu J, Hua Y, Cai Z, Sun W. MYLK4 promotes tumor progression through the activation of epidermal growth factor receptor signaling in osteosarcoma. J Exp Clin Cancer Res 2021; 40:166. [PMID: 33980265 PMCID: PMC8114533 DOI: 10.1186/s13046-021-01965-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 04/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Osteosarcoma (OS) is the most common primary bone cancer in adolescents and lung metastasis is the leading cause of death in patients with OS. However, the molecular mechanisms that promote OS growth and metastasis remain unknown. METHODS We investigated the expression of myosin light chain kinase family members between metastasis and non-metastasis patients in the TARGET database and ensured that only myosin light chain kinase family member 4 (MYLK4) had higher expression in metastatic osteosarcoma patients. Then we confirmed the results by immunohistochemistry (IHC) and Western blotting (WB) of OS tissues. The effect of MYLK4 on the metastasis and proliferation of OS cells was investigated by wound healing, Transwell and colony-formation assays. Mass spectrum analysis was used to ensure the new binding protein of MYLK4. Tissue microarrays analysis was used to show the correlation between MYLK4 and pEGFR (Y1068). A series of in vivo experiments were conducted to reveal the mechanisms by which MYLK4 modulated the metastasis and proliferation of OS. RESULTS Myosin Light Chain Kinase Family Member 4 (MYLK4) was significantly upregulated in metastatic human OS tissues. Growth and metastasis of OS could be accelerated by MYLK4 overexpression, whereas silencing MYLK4 expression resulted in decreased cell growth and metastasis. Mechanistically, mass spectrum analysis showed that MYLK4 interacted with the epidermal growth factor receptor (EGFR) in osteosarcoma cells and promoted growth and metastasis via the EGFR signaling pathway. Tissue microarrays analysis also showed that MYLK4 expression had a positive correlation with the expression of pEGFR (Y1068). Moreover, the EGFR inhibitor gefitinib could partially reverse the effect of cell proliferation and metastasis caused by MYLK4 overexpression. Importantly, the combination of MYLK4 and EGFR inhibitors had synergistic effects on growth and metastasis of OS in vitro and in vivo. CONCLUSION Our results indicate that MYLK4 promotes OS growth and metastasis by activating the EGFR signaling pathway and can be a novel therapeutic target for the treatment of OS patients.
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Affiliation(s)
- Mengkai Yang
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Tao Zhang
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China.
| | - Yangfeng Zhang
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Xiaojun Ma
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Jing Han
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Ke Zeng
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Yafei Jiang
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Zongyi Wang
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Zhuoying Wang
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Jing Xu
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Yingqi Hua
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China
| | - Zhengdong Cai
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China.
| | - Wei Sun
- Department of Orthopedics, Shanghai Bone Tumor Institution, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, P. R. China.
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8
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Ostberg NP, Zafar MA, Ziganshin BA, Elefteriades JA. The Genetics of Thoracic Aortic Aneurysms and Dissection: A Clinical Perspective. Biomolecules 2020; 10:E182. [PMID: 31991693 PMCID: PMC7072177 DOI: 10.3390/biom10020182] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Thoracic aortic aneurysm and dissection (TAAD) affects many patients globally and has high mortality rates if undetected. Once thought to be solely a degenerative disease that afflicted the aorta due to high pressure and biomechanical stress, extensive investigation of the heritability and natural history of TAAD has shown a clear genetic basis for the disease. Here, we review both the cellular mechanisms and clinical manifestations of syndromic and non-syndromic TAAD. We particularly focus on genes that have been linked to dissection at diameters <5.0 cm, the current lower bound for surgical intervention. Genetic screening tests to identify patients with TAAD associated mutations that place them at high risk for dissection are also discussed.
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Affiliation(s)
- Nicolai P. Ostberg
- Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT 06510, USA; (N.P.O.); (M.A.Z.); (B.A.Z.)
| | - Mohammad A. Zafar
- Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT 06510, USA; (N.P.O.); (M.A.Z.); (B.A.Z.)
| | - Bulat A. Ziganshin
- Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT 06510, USA; (N.P.O.); (M.A.Z.); (B.A.Z.)
- Department of Cardiovascular and Endovascular Surgery, Kazan State Medical University, 420012 Kazan, Russia
| | - John A. Elefteriades
- Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT 06510, USA; (N.P.O.); (M.A.Z.); (B.A.Z.)
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9
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Islam MS, Kaji N, Mikawa S, Yang Q, Kusabe M, Hori M, Ozaki H. Induction of myosin light chain kinase and CPI-17 by TGF-β accelerates contractile activity in intestinal epithelial cells. J Vet Med Sci 2018; 80:977-984. [PMID: 29695674 PMCID: PMC6021892 DOI: 10.1292/jvms.17-0684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Epithelial-mesenchymal transition (EMT) is an orchestral and functional change in epithelial cells. Many signaling pathways are involved in EMT, and transforming growth factor-beta (TGF-β) is considered to be one of the most important factors in induction of EMT. In this study, we treated the rat intestinal epithelial cell line (IEC-6) with TGF-β1 as a signaling stimulant. Gross analysis of IEC-6 cells showed typical characteristics of epithelial cells such as cuboidal morphology and cell-cell contact, whereas treatment with TGF-β1 (10 ng/ml-1) for 7 days produced robust, spindle-shaped morphology. Immunocytochemistry analysis showed distinct E-cadherin staining in IEC-6 cells, but weak and faint in EMT cells. EMT cells showed positive expression of α-SMA and tenascin-C but IEC-6 cells did not. Quantitative real-time PCR analysis showed that myosin light chain kinase and C-kinase potentiated protein phosphatase-1 inhibitor (CPI-17) mRNAs were significantly upregulated in EMT cells. Immunocytochemistry analysis also showed that EMT cells strongly expressed CPI-17 but IEC-6 cells did not. A collagen gel contraction assay revealed that EMT cells had greatly increased contraction compared with control cells. These results suggest that the increased contractile activity induced by TGF-β in EMT cells may be attributable to the upregulation of molecules responsible for myosin phosphorylation/de-phosphorylation.
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Affiliation(s)
- Md Shafiqul Islam
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Noriyuki Kaji
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Shoma Mikawa
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Qunhui Yang
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Moriaki Kusabe
- Development of Advanced Technology Laboratory Research Center for Food Safety, The University of Tokyo, Tokyo 113-8657, Japan
| | - Masatoshi Hori
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Hiroshi Ozaki
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
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10
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Huang H, Scheffler TL, Gerrard DE, Larsen MR, Lametsch R. Quantitative Proteomics and Phosphoproteomics Analysis Revealed Different Regulatory Mechanisms of Halothane and Rendement Napole Genes in Porcine Muscle Metabolism. J Proteome Res 2018; 17:2834-2849. [PMID: 29916714 DOI: 10.1021/acs.jproteome.8b00294] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pigs with the Halothane (HAL) or Rendement Napole (RN) gene mutations demonstrate abnormal muscle energy metabolism patterns and produce meat with poor quality, classified as pale, soft, and exudative (PSE) meat, but it is not well understood how HAL and RN mutations regulate glucose and energy metabolism in porcine muscle. To investigate the potential signaling pathways and phosphorylation events related to these mutations, muscle samples were collected from four genotypes of pigs, wild type, RN, HAL, and RN-HAL double mutations, and subjected to quantitative proteomic and phosphoproteomic analysis using the TiO2 enrichment strategy. The study led to the identification of 932 proteins from the nonmodified peptide fractions and 1885 phosphoproteins with 9619 phosphorylation sites from the enriched fractions. Among them, 128 proteins at total protein level and 323 phosphosites from 91 phosphoproteins were significantly regulated in mutant genotypes. The quantitative analysis revealed that the RN mutation mainly affected the protein expression abundance in muscle. Specifically, high expression was observed for proteins related to mitochondrial respiratory chain and energy metabolism, thereby enhancing the muscle oxidative capacity. The high content of UDP-glucose pyrophosphorylase 2 (UGP2) in RN mutant animals may contribute to high glycogen storage. However, the HAL mutation mainly contributes to the up-regulation of phosphorylation in proteins related to calcium signaling, muscle contraction, glycogen, glucose, and energy metabolism, and cellular stress. The increased phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CAMK2) in HAL mutation may act as a key regulator in these processes of muscle. Our findings indicate the different regulatory mechanisms of RN and HAL mutations in relation to porcine muscle energy metabolism and meat quality.
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Affiliation(s)
- Honggang Huang
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , DK-5230 Odense M , Denmark.,Department of Food Science, Faculty of Science , University of Copenhagen , DK-1958 Frederiksberg , Denmark.,The Danish Diabetes Academy , 5000 Odense , Denmark.,Arla Foods Ingredients Group P/S , Soenderupvej 26 , 6920 Videbaek , Denmark
| | - Tracy L Scheffler
- Department of Animal Sciences , University of Florida , Gainesville , Florida 32608 , United States
| | - David E Gerrard
- Department of Animal and Poultry Sciences , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology , University of Southern Denmark , DK-5230 Odense M , Denmark
| | - René Lametsch
- Department of Food Science, Faculty of Science , University of Copenhagen , DK-1958 Frederiksberg , Denmark
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11
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Lin J, He Y, Chen L, Chen X, Zang S, Lin W. MYLK promotes hepatocellular carcinoma progression through regulating cytoskeleton to enhance epithelial-mesenchymal transition. Clin Exp Med 2018; 18:523-533. [PMID: 29855744 DOI: 10.1007/s10238-018-0509-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 05/24/2018] [Indexed: 11/24/2022]
Abstract
Myosin light chain kinase (MYLK) is found to catalyze the phosphorylation of myosin light chains (MLC) and regulate invasion and metastasis in some malignancies. However, there is little knowledge on the role of MYLK in hepatocellular carcinoma (HCC), and no studies have been conducted to investigate the mechanisms underlying MYLK-mediated promotion of HCC invasion and metastasis until now. In this study, we investigated the expression of MYLK in 50 pairs of human HCC and adjacent liver specimens. High MYLK expression was significantly correlated with aggressive clinicopathological features including tumor encapsulation, microvascular invasion and metastasis. In vitro assays showed that shRNA-induced MYLK knockdown significantly inhibited the wound-healing ability of HCC cells and the ability to migrate and invade through Matrigel. We next uncovered that MYLK knockdown resulted in a reduction in the number of F-actin stress fibers, disorganization of F-actin architectures and morphological alterations of HCC cells. Phosphorylated MLC, rather than total MLC, was found to be markedly reduced in response to downregulation of MYLK expression, and MYLK-regulated actin cytoskeleton through phosphorylating MLC in HCC cells. In addition, Western blotting assay revealed downregulation of the epithelial marker E-cadherin and upregulation of mesenchymal markers Vimentin, N-cadherin and Snail. Taken together, our findings indicate that MYLK promotes HCC progression by altering cytoskeleton to enhance epithelial-mesenchymal transition (EMT).
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Affiliation(s)
- Jie Lin
- Department of Pathology, Fujian Provincial Hospital, Fuzhou, 350001, China.,Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Yihui He
- Department of Pathology, Fujian Provincial Hospital, Fuzhou, 350001, China.,Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Lingfeng Chen
- Department of Pathology, Fujian Provincial Hospital, Fuzhou, 350001, China.,Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Xiaoyan Chen
- Department of Pathology, Fujian Provincial Hospital, Fuzhou, 350001, China.,Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001, China
| | - Shengbing Zang
- Department of Pathology, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - Wansong Lin
- Laboratory of Immuno-Oncology, Fujian Cancer Hospital and Fujian Medical University Cancer Hospital, No.420, Fuma Road, Jinan District, Fuzhou City, 350014, Fujian Province, China. .,Fujian Provincial Key Laboratory of Translational Cancer Medicine, Fuzhou, 350014, China.
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12
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Baumann F, Bauer MS, Rees M, Alexandrovich A, Gautel M, Pippig DA, Gaub HE. Increasing evidence of mechanical force as a functional regulator in smooth muscle myosin light chain kinase. eLife 2017; 6. [PMID: 28696205 PMCID: PMC5505704 DOI: 10.7554/elife.26473] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/20/2017] [Indexed: 11/18/2022] Open
Abstract
Mechanosensitive proteins are key players in cytoskeletal remodeling, muscle contraction, cell migration and differentiation processes. Smooth muscle myosin light chain kinase (smMLCK) is a member of a diverse group of serine/threonine kinases that feature cytoskeletal association. Its catalytic activity is triggered by a conformational change upon Ca2+/calmodulin (Ca2+/CaM) binding. Due to its significant homology with the force-activated titin kinase, smMLCK is suspected to be also regulatable by mechanical stress. In this study, a CaM-independent activation mechanism for smMLCK by mechanical release of the inhibitory elements is investigated via high throughput AFM single-molecule force spectroscopy. The characteristic pattern of transitions between different smMLCK states and their variations in the presence of different substrates and ligands are presented. Interaction between kinase domain and regulatory light chain (RLC) substrate is identified in the absence of CaM, indicating restored substrate-binding capability due to mechanically induced removal of the auto-inhibitory regulatory region. DOI:http://dx.doi.org/10.7554/eLife.26473.001
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Affiliation(s)
- Fabian Baumann
- Chair for Applied Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Magnus Sebastian Bauer
- Chair for Applied Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany.,Center for Integrated Protein Science Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Martin Rees
- Randall Division of Cell and Molecular Biophysics, King's College London BHF Centre of Research Excellence, London, United Kingdom
| | - Alexander Alexandrovich
- Randall Division of Cell and Molecular Biophysics, King's College London BHF Centre of Research Excellence, London, United Kingdom
| | - Mathias Gautel
- Randall Division of Cell and Molecular Biophysics, King's College London BHF Centre of Research Excellence, London, United Kingdom
| | - Diana Angela Pippig
- Chair for Applied Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Hermann Eduard Gaub
- Chair for Applied Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Munich, Germany
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13
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Arora PD, Di Gregorio M, He P, McCulloch CA. TRPV4 mediates the Ca 2+ influx required for the interaction between flightless-1 and non-muscle myosin, and collagen remodeling. J Cell Sci 2017; 130:2196-2208. [PMID: 28526784 DOI: 10.1242/jcs.201665] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 05/14/2017] [Indexed: 12/15/2022] Open
Abstract
Fibroblasts remodel extracellular matrix collagen, in part, through phagocytosis. This process requires formation of cell extensions, which in turn involves interaction of the actin-binding protein flightless-1 (FliI) with non-muscle myosin IIA (NMMIIA; heavy chain encoded by MYH9) at cell-matrix adhesion sites. As Ca2+ plays a central role in controlling actomyosin-dependent functions, we examined how Ca2+ controls the generation of cell extensions and collagen remodeling. Ratio fluorimetry demonstrated localized Ca2+ influx at the extensions of fibroblasts. Western blotting and quantitative (q)PCR showed high expression levels of the Ca2+-permeable transient receptor potential vanilloid-4 (TRPV4) channel, which co-immunoprecipitated with β1 integrin and localized to adhesions. Treatment with α2β1-integrin-blocking antibody or the TRPV4-specific antagonist AB159908, as well as reduction of TRPV4 expression through means of siRNA, blocked Ca2+ influx. These treatments also inhibited the interaction of FliI with NMMIIA, reduced the number and length of cell extensions, and blocked collagen remodeling. Pulldown assays showed that Ca2+ depletion inhibited the interaction of purified FliI with NMMIIA filaments. Fluorescence resonance energy transfer experiments showed that FliI-NMMIIA interactions require Ca2+ influx. We conclude that Ca2+ influx through the TRPV4 channel regulates FliI-NMMIIA interaction, which in turn enables generation of the cell extensions essential for collagen remodeling.
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Affiliation(s)
- Pamma D Arora
- University of Toronto, Room 244, Fitzgerald Building, 150 College Street, Toronto, Ontario, M5S 3E2, Canada
| | - Madeleine Di Gregorio
- University of Toronto, Room 244, Fitzgerald Building, 150 College Street, Toronto, Ontario, M5S 3E2, Canada
| | - Pei He
- University of Toronto, Room 244, Fitzgerald Building, 150 College Street, Toronto, Ontario, M5S 3E2, Canada
| | - Christopher A McCulloch
- University of Toronto, Room 244, Fitzgerald Building, 150 College Street, Toronto, Ontario, M5S 3E2, Canada
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14
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Hudson CA, López Bernal A. Phosphorylation of proteins during human myometrial contractions: A phosphoproteomic approach. Biochem Biophys Res Commun 2017; 482:1393-1399. [DOI: 10.1016/j.bbrc.2016.12.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 12/07/2016] [Indexed: 12/12/2022]
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15
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Prasad AM, Ketsawatsomkron P, Nuno DW, Koval OM, Dibbern ME, Venema AN, Sigmund CD, Lamping KG, Grumbach IM. Role of CaMKII in Ang-II-dependent small artery remodeling. Vascul Pharmacol 2016; 87:172-179. [PMID: 27658984 DOI: 10.1016/j.vph.2016.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/22/2016] [Accepted: 09/18/2016] [Indexed: 01/21/2023]
Abstract
Angiotensin-II (Ang-II) is a well-established mediator of vascular remodeling. The multifunctional calcium-calmodulin-dependent kinase II (CaMKII) is activated by Ang-II and regulates Erk1/2 and Akt-dependent signaling in cultured smooth muscle cells in vitro. Its role in Ang-II-dependent vascular remodeling in vivo is far less defined. Using a model of transgenic CaMKII inhibition selectively in smooth muscle cells, we found that CaMKII inhibition exaggerated remodeling after chronic Ang-II treatment and agonist-dependent vasoconstriction in second-order mesenteric arteries. These findings were associated with increased mRNA and protein expression of smooth muscle structural proteins. As a potential mechanism, CaMKII reduced serum response factor-dependent transcriptional activity. In summary, our findings identify CaMKII as an important regulator of smooth muscle function in Ang-II hypertension in vivo.
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Affiliation(s)
- Anand M Prasad
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States
| | - Pimonrat Ketsawatsomkron
- Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Daniel W Nuno
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States; Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Olha M Koval
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States
| | - Megan E Dibbern
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States
| | - Ashlee N Venema
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States
| | - Curt D Sigmund
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States; Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, United States; Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, United States
| | - Kathryn G Lamping
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States; Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, United States; Iowa City VA Healthcare System, Iowa City, United States
| | - Isabella M Grumbach
- Department of Medicine, Carver College, University of Iowa, Iowa City, United States; Iowa City VA Healthcare System, Iowa City, United States.
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16
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Karim ZA, Vemana HP, Khasawneh FT. MALT1-ubiquitination triggers non-genomic NF-κB/IKK signaling upon platelet activation. PLoS One 2015; 10:e0119363. [PMID: 25748427 PMCID: PMC4352082 DOI: 10.1371/journal.pone.0119363] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/13/2015] [Indexed: 11/19/2022] Open
Abstract
We have recently shown that IKK complex plays an important non-genomic role in platelet function, i.e., regulates SNARE machinery-dependent membrane fusion. In this connection, it is well known that MALT1, whose activity is modulated by proteasome, plays an important role in the regulation of IKK complex. Therefore, the present studies investigated the mechanism by which IKK signaling is regulated in the context of the platelet proteasome. It was found that platelets express a functional proteasome, and form CARMA/MALT1/Bcl10 (CBM) complex when activated. Using a pharmacological inhibitor, the proteasome was found to regulate platelet function (aggregation, integrin activation, secretion, phosphatidylserine exposure and changes in intracellular calcium). It was also found to regulate thrombogenesis and physiologic hemostasis. We also observed, upon platelet activation, that MALT1 is ubiquitinated, and this coincides with the activation of the IKK/NF-κB-signaling pathway. Finally, we observed that the proteasome inhibitor blocks CBM complex formation and the interaction of IKKγ and MALT1; abrogates SNARE formation, and the association of MALT1 with TAK1 and TAB2, which are upstream of the CBM complex. Thus, our data demonstrate that MALT1 ubiquitination is critical for the engagement of CBM and IKK complexes, thereby directing platelet signals to the NF-κB pathway.
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Affiliation(s)
- Zubair A. Karim
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, 91766, United States of America
- * E-mail:
| | - Hari Priya Vemana
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, 91766, United States of America
| | - Fadi T. Khasawneh
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, 91766, United States of America
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17
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Hildebrandt JP. Pore-forming virulence factors of Staphylococcus aureus destabilize epithelial barriers-effects of alpha-toxin in the early phases of airway infection. AIMS Microbiol 2015. [DOI: 10.3934/microbiol.2015.1.11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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18
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Lian L, Suzuki A, Hayes V, Saha S, Han X, Xu T, Yates JR, Poncz M, Kashina A, Abrams CS. Loss of ATE1-mediated arginylation leads to impaired platelet myosin phosphorylation, clot retraction, and in vivo thrombosis formation. Haematologica 2013; 99:554-60. [PMID: 24293517 DOI: 10.3324/haematol.2013.093047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Protein arginylation by arginyl-transfer RNA protein transferase (ATE1) is emerging as a regulator protein function that is reminiscent of phosphorylation. For example, arginylation of β-actin has been found to regulate lamellipodial formation at the leading edge in fibroblasts. This finding suggests that similar functions of β-actin in other cell types may also require arginylation. Here, we have tested the hypothesis that ATE1 regulates the cytoskeletal dynamics essential for in vivo platelet adhesion and thrombus formation. To test this hypothesis, we generated conditional knockout mice specifically lacking ATE1 in their platelets and in their megakaryocytes and analyzed the role of arginylation during platelet activation. Surprisingly, rather than finding an impairment of the actin cytoskeleton structure and its rearrangement during platelet activation, we observed that the platelet-specific ATE1 knockout led to enhanced clot retraction and in vivo thrombus formation. This effect might be regulated by myosin II contractility since it was accompanied by enhanced phosphorylation of the myosin regulatory light chain on Ser19, which is an event that activates myosin in vivo. Furthermore, ATE1 and myosin co-immunoprecipitate from platelet lysates. This finding suggests that these proteins directly interact within platelets. These results provide the first evidence that arginylation is involved in phosphorylation-dependent protein regulation, and that arginylation affects myosin function in platelets during clot retraction.
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19
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Prasad AM, Nuno DW, Koval OM, Ketsawatsomkron P, Li W, Li H, Shen FY, Joiner MLA, Kutschke W, Weiss RM, Sigmund CD, Anderson ME, Lamping KG, Grumbach IM. Differential control of calcium homeostasis and vascular reactivity by Ca2+/calmodulin-dependent kinase II. Hypertension 2013; 62:434-41. [PMID: 23753415 DOI: 10.1161/hypertensionaha.113.01508] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The multifunctional Ca(2+)/calmodulin-dependent kinase II (CaMKII) is activated by vasoconstrictors in vascular smooth muscle cells (VSMC), but its impact on vasoconstriction remains unknown. We hypothesized that CaMKII inhibition in VSMC decreases vasoconstriction. Using novel transgenic mice that express the inhibitor peptide CaMKIIN in smooth muscle (TG SM-CaMKIIN), we investigated the effect of CaMKII inhibition on L-type Ca(2+) channel current (ICa), cytoplasmic and sarcoplasmic reticulum Ca(2+), and vasoconstriction in mesenteric arteries. In mesenteric VSMC, CaMKII inhibition significantly reduced action potential duration and the residual ICa 50 ms after peak amplitude, indicative of loss of L-type Ca(2+) channel-dependent ICa facilitation. Treatment with angiotensin II or phenylephrine increased the intracellular Ca(2+) concentration in wild-type but not TG SM-CaMKIIN VSMC. The difference in intracellular Ca(2+) concentration was abolished by pretreatment with nifedipine, an L-type Ca(2+) channel antagonist. In TG SM-CaMKIIN VSMC, the total sarcoplasmic reticulum Ca(2+) content was reduced as a result of diminished sarcoplasmic reticulum Ca(2+) ATPase activity via impaired derepression of the sarcoplasmic reticulum Ca(2+) ATPase inhibitor phospholamban. Despite the differences in intracellular Ca(2+) concentration, CaMKII inhibition did not alter myogenic tone or vasoconstriction of mesenteric arteries in response to KCl, angiotensin II, and phenylephrine. However, it increased myosin light chain kinase activity. These data suggest that CaMKII activity maintains intracellular calcium homeostasis but is not required for vasoconstriction of mesenteric arteries.
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Affiliation(s)
- Anand M Prasad
- Department of Medicine, University of Iowa, Iowa City, IA 52242, USA
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20
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Tsai MH, Kamm KE, Stull JT. Signalling to contractile proteins by muscarinic and purinergic pathways in neurally stimulated bladder smooth muscle. J Physiol 2012; 590:5107-21. [PMID: 22890701 DOI: 10.1113/jphysiol.2012.235424] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Urinary bladder smooth muscle contraction is triggered by parasympathetic nerves, which release ATP and acetylcholine (ACh) that bind to purinergic and muscarinic receptors, respectively. Neuronal signalling may thus elicit myosin regulatory light chain (RLC) phosphorylation and contraction through the combined, but distinct contributions of these receptors. Both receptors mediate Ca2+ influx whereas muscarinic receptors may also recruit Ca2+-sensitization mechanisms. Using transgenic mice expressing calmodulin sensor myosin light chain kinase (MLCK) in smooth muscles, the effects of suramin/α,β-methylene ATP (α,β-meATP) (purinergic inhibition) or atropine (muscarinic inhibition) on neurally stimulated elevation of [Ca2+]i, MLCK activation, force and phosphorylation of RLC, myosin light chain phosphatase (MLCP) targeting subunit MYPT1 and MLCP inhibitor protein CPI-17 were examined. Electric field stimulation (EFS) increased [Ca2+]i, MLCK activation and concomitant force in a frequency-dependent manner. The dependence of force on [Ca2+]i and MLCK activation decreased with time suggesting increased Ca2+ sensitization in the late contractile phase. RLC and CPI-17 phosphorylation increased upon stimulation with maximal responses at 20 Hz; both responses were attenuated by atropine, but only RLC phosphorylation was inhibited by suramin/α,β-meATP. Antagonism of purinergic receptors suppressed maximal MLCK activation to a greater extent in the early contractile phase than in the late contractile phase; atropine had the opposite effect. A frequency- and time-dependent increase in MLCK phosphorylation explained the desensitization of MLCK to Ca2+, since MLCK activation declined more rapidly than [Ca2+]i. EFS elicited little or no effect on MYPT1 Thr696 or 850 phosphorylation. Thus, purinergic Ca2+ signals provide the initial activation of MLCK with muscarinic receptors supporting sustained responses. Activation of muscarinic receptors recruits CPI-17, but not MYPT1-mediated Ca2+ sensitization. Furthermore, nerve-released ACh also initiates signalling cascades leading to phosphorylation-dependent desensitization of MLCK.
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Affiliation(s)
- Ming-Ho Tsai
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9040, USA
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21
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Morgado M, Cairrão E, Santos-Silva AJ, Verde I. Cyclic nucleotide-dependent relaxation pathways in vascular smooth muscle. Cell Mol Life Sci 2012; 69:247-66. [PMID: 21947498 PMCID: PMC11115151 DOI: 10.1007/s00018-011-0815-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 08/21/2011] [Accepted: 08/23/2011] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle tone is controlled by a balance between the cellular signaling pathways that mediate the generation of force (vasoconstriction) and release of force (vasodilation). The initiation of force is associated with increases in intracellular calcium concentrations, activation of myosin light-chain kinase, increases in the phosphorylation of the regulatory myosin light chains, and actin-myosin crossbridge cycling. There are, however, several signaling pathways modulating Ca(2+) mobilization and Ca(2+) sensitivity of the contractile machinery that secondarily regulate the contractile response of vascular smooth muscle to receptor agonists. Among these regulatory mechanisms involved in the physiological regulation of vascular tone are the cyclic nucleotides (cAMP and cGMP), which are considered the main messengers that mediate vasodilation under physiological conditions. At least four distinct mechanisms are currently thought to be involved in the vasodilator effect of cyclic nucleotides and their dependent protein kinases: (1) the decrease in cytosolic calcium concentration ([Ca(2+)]c), (2) the hyperpolarization of the smooth muscle cell membrane potential, (3) the reduction in the sensitivity of the contractile machinery by decreasing the [Ca(2+)]c sensitivity of myosin light-chain phosphorylation, and (4) the reduction in the sensitivity of the contractile machinery by uncoupling contraction from myosin light-chain phosphorylation. This review focuses on each of these mechanisms involved in cyclic nucleotide-dependent relaxation of vascular smooth muscle under physiological conditions.
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Affiliation(s)
- Manuel Morgado
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Elisa Cairrão
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - António José Santos-Silva
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Ignacio Verde
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
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22
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Hong F, Haldeman BD, Jackson D, Carter M, Baker JE, Cremo CR. Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys 2011. [PMID: 21565153 DOI: 10.1016/j.abb.2011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca(2+)-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.
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Affiliation(s)
- Feng Hong
- Department of Biochemistry and Molecular Biology, University of Nevada School of Medicine, Reno, 89557, USA
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23
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Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys 2011; 510:135-46. [PMID: 21565153 DOI: 10.1016/j.abb.2011.04.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 04/22/2011] [Accepted: 04/25/2011] [Indexed: 11/23/2022]
Abstract
The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca(2+)-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.
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24
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Perrino BA. Regulation of gastrointestinal motility by Ca2+/calmodulin-stimulated protein kinase II. Arch Biochem Biophys 2011; 510:174-81. [PMID: 21443856 DOI: 10.1016/j.abb.2011.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 03/15/2011] [Accepted: 03/21/2011] [Indexed: 12/30/2022]
Abstract
Gastrointestinal (GI) motility ultimately depends upon the contractile activity of the smooth muscle cells of the tunica muscularis. Integrated functioning of multiple tissues and cell types, including enteric neurons and interstitial cells of Cajal (ICC) is necessary to generate coordinated patterns of motor activity that control the movement of material through the digestive tract. The neurogenic mechanisms that govern GI motility patterns are superimposed upon intrinsic myogenic mechanisms regulating smooth muscle cell excitability. Several mechanisms regulate smooth muscle cell responses to neurogenic inputs, including the multifunctional Ca(2+)/calmodulin-stimulated protein kinase II (CaMKII). CaMKII can be activated by Ca(2+) transients from both extracellular and intracellular sources. Prolonging the activities of Ca(2+)-sensitive K(+) channels in the plasma membrane of GI smooth muscle cells is an important regulatory mechanism carried out by CaMKII. Phospholamban (PLN) phosphorylation by CaMKII activates the sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA), increasing both the rate of Ca(2+) clearance from the myoplasm and the frequency of localized Ca(2+) release events from intracellular stores. Overall, CaMKII appears to moderate GI smooth muscle cell excitability. Finally, transcription factor activities may be facilitated by the neutralization of HDAC4 by CaMKII phosphorylation, which may contribute to the phenotypic plasticity of GI smooth muscle cells.
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Affiliation(s)
- Brian A Perrino
- Department of Physiology and Cell Biology, Center of Biomedical Research Excellence, University of Nevada School of Medicine, Reno, 89557, USA.
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25
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Atg1-mediated myosin II activation regulates autophagosome formation during starvation-induced autophagy. EMBO J 2010; 30:636-51. [PMID: 21169990 DOI: 10.1038/emboj.2010.338] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 11/24/2010] [Indexed: 01/01/2023] Open
Abstract
Autophagy is a membrane-mediated degradation process of macromolecule recycling. Although the formation of double-membrane degradation vesicles (autophagosomes) is known to have a central role in autophagy, the mechanism underlying this process remains elusive. The serine/threonine kinase Atg1 has a key role in the induction of autophagy. In this study, we show that overexpression of Drosophila Atg1 promotes the phosphorylation-dependent activation of the actin-associated motor protein myosin II. A novel myosin light chain kinase (MLCK)-like protein, Spaghetti-squash activator (Sqa), was identified as a link between Atg1 and actomyosin activation. Sqa interacts with Atg1 through its kinase domain and is a substrate of Atg1. Significantly, myosin II inhibition or depletion of Sqa compromised the formation of autophagosomes under starvation conditions. In mammalian cells, we found that the Sqa mammalian homologue zipper-interacting protein kinase (ZIPK) and myosin II had a critical role in the regulation of starvation-induced autophagy and mammalian Atg9 (mAtg9) trafficking when cells were deprived of nutrients. Our findings provide evidence of a link between Atg1 and the control of Atg9-mediated autophagosome formation through the myosin II motor protein.
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26
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Bodenstein C, Knoke B, Marhl M, Perc M, Schuster S. Using Jensen's inequality to explain the role of regular calcium oscillations in protein activation. Phys Biol 2010; 7:036009. [PMID: 20834115 DOI: 10.1088/1478-3975/7/3/036009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Oscillations of cytosolic Ca(2 +) are very important for cellular signalling in excitable and non-excitable cells. The information of various extracellular stimuli is encoded into oscillating patterns of Ca(2 +) that subsequently lead to the activation of different Ca(2 +)-sensitive target proteins in the cell. The question remains, however, why this information is transmitted by means of an oscillating rather than a constant signal. Here we show that, in fact, Ca(2 +) oscillations can achieve a better activation of target proteins than a comparable constant signal with the same amount of Ca(2 +) used. For this we use Jensen's inequality that describes the relation between the function value of the average of a set of argument values and the average of the function values of the arguments from that set. We analyse the role of the cooperativity of the binding of Ca(2 +) and of zero-order ultrasensitivity, which are two properties that are often observed in experiments on the activation of Ca(2 +)-sensitive target proteins. Our results apply to arbitrary oscillation shapes and a very general decoding model, thus generalizing the observations of several previous studies. We compare our results with data from experimental studies investigating the activation of nuclear factor of activated T cells (NFAT) and Ras by oscillatory and constant signals. Although we are restricted to specific approximations due to the lack of detailed kinetic data, we find good qualitative agreement with our theoretical predictions.
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Affiliation(s)
- C Bodenstein
- Department of Bioinformatics, Friedrich Schiller University Jena, Ernst-Abbe-Platz 2, D-07743 Jena, Germany.
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27
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Ulke-Lemée A, MacDonald JA. Opportunities to Target Specific Contractile Abnormalities with Smooth Muscle Protein Kinase Inhibitors. Pharmaceuticals (Basel) 2010; 3:1739-1760. [PMID: 27713327 PMCID: PMC4033950 DOI: 10.3390/ph3061739] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 04/26/2010] [Accepted: 05/24/2010] [Indexed: 12/14/2022] Open
Abstract
Smooth muscle is a major component of most hollow organ systems (e.g., airways, vasculature, bladder and gut/gastrointestine); therefore, the coordinated regulation of contraction is a key property of smooth muscle. When smooth muscle functions normally, it contributes to general health and wellness, but its dysfunction is associated with morbidity and mortality. Rho-associated protein kinase (ROCK) is central to calcium-independent, actomyosin-mediated contractile force generation in the vasculature, thereby playing a role in smooth muscle contraction, cell motility and adhesion. Recent evidence supports an important role for ROCK in the increased vasoconstriction and remodeling observed in various models of hypertension. This review will provide a commentary on the development of specific ROCK inhibitors and their clinical application. Fasudil will be discussed as an example of bench-to-bedside development of a clinical therapeutic that is used to treat conditions of vascular hypercontractility. Due to the wide spectrum of biological processes regulated by ROCK, many additional clinical indications might also benefit from ROCK inhibition. Apart from the importance of ROCK in smooth muscle contraction, a variety of other protein kinases are known to play similar roles in regulating contractile force. The zipper-interacting protein kinase (ZIPK) and integrin-linked kinase (ILK) are two well-described regulators of contraction. The relative contribution of each kinase to contraction depends on the muscle bed as well as hormonal and neuronal stimulation. Unfortunately, specific inhibitors for ZIPK and ILK are still in the development phase, but the success of fasudil suggests that inhibitors for these other kinases may also have valuable clinical applications. Notably, the directed inhibition of ZIPK with a pseudosubstrate molecule shows unexpected effects on the contractility of gastrointestinal smooth muscle.
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Affiliation(s)
- Annegret Ulke-Lemée
- Smooth Muscle Research Group and Department of Biochemistry & Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada.
| | - Justin A MacDonald
- Smooth Muscle Research Group and Department of Biochemistry & Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada.
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28
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Possible participation of calmodulin in the decondensation of nuclei isolated from guinea pig spermatozoa. ZYGOTE 2009; 18:217-29. [PMID: 19939332 DOI: 10.1017/s0967199409990220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The guinea pig spermatozoid nucleus contains actin, myosin, spectrin and cytokeratin. Also, it has been reported that phalloidin and/or 2,3-butanedione monoxime retard the sperm nuclear decondensation caused by heparin, suggesting a role for F-actin and myosin in nuclear stability. The presence of an F-actin/myosin dynamic system in these nuclei led us to search for proteins usually related to this system. In guinea pig sperm nuclei we detected calmodulin, F-actin, the myosin light chain and an actin-myosin complex. To define whether calmodulin participates in nuclear-dynamics, the effect of the calmodulin antagonists W5, W7 and calmidazolium was tested on the decondensation of nuclei promoted by either heparin or by a Xenopus laevis egg extract. All antagonists inhibited both the heparin- and the X. laevis egg extract-mediated nuclear decondensation. Heparin-mediated decondensation was faster and led to loss of nuclei. The X. laevis egg extract-promoted decondensation was slower and did not result in loss of the decondensed nuclei. It is suggested that in guinea pig sperm calmodulin participates in the nuclear decondensation process.
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29
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Ding HL, Ryder JW, Stull JT, Kamm KE. Signaling processes for initiating smooth muscle contraction upon neural stimulation. J Biol Chem 2009; 284:15541-8. [PMID: 19349274 DOI: 10.1074/jbc.m900888200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Relationships among biochemical signaling processes involved in Ca2+/calmodulin (CaM)-dependent phosphorylation of smooth muscle myosin regulatory light chain (RLC) by myosin light chain kinase (MLCK) were determined. A genetically-encoded biosensor MLCK for measuring Ca(2+)-dependent CaM binding and activation was expressed in smooth muscles of transgenic mice. We performed real-time evaluations of the relationships among [Ca2+](i), MLCK activation, and contraction in urinary bladder smooth muscle strips neurally stimulated for 3 s. Latencies for the onset of [Ca2+](i) and kinase activation were 55 +/- 8 and 65 +/- 6 ms, respectively. Both increased with RLC phosphorylation at 100 ms, whereas force latency was 109 +/- 3 ms. [Ca2+](i), kinase activation, and RLC phosphorylation responses were maximal by 1.2 s, whereas force increased more slowly to a maximal value at 3 s. A delayed temporal response between RLC phosphorylation and force is probably due to mechanical effects associated with elastic elements in the tissue. MLCK activation partially declined at 3 s of stimulation with no change in [Ca2+](i) and also declined more rapidly than [Ca2+](i) during relaxation. The apparent desensitization of MLCK to Ca2+ activation appears to be due to phosphorylation in its calmodulin binding segment. Phosphorylation of two myosin light chain phosphatase regulatory proteins (MYPT1 and CPI-17) or a protein implicated in strengthening membrane adhesion complexes for force transmission (paxillin) did not change during force development. Thus, neural stimulation leads to rapid increases in [Ca2+](i), MLCK activation, and RLC phosphorylation in phasic smooth muscle, showing a tightly coupled Ca2+ signaling complex as an elementary mechanism initiating contraction.
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Affiliation(s)
- Hai-Lei Ding
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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30
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Ihara E, MacDonald JA. The regulation of smooth muscle contractility by zipper-interacting protein kinase. Can J Physiol Pharmacol 2007; 85:79-87. [PMID: 17487247 DOI: 10.1139/y06-103] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Smooth muscle contractility is mainly regulated by phosphorylation of the 20 kDa myosin light chains (LC20), a process that is controlled by the opposing activities of myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP). Recently, intensive research has revealed that various protein kinase networks including Rho-kinase, integrin-linked kinase, zipper-interacting protein kinase (ZIPK), and protein kinase C (PKC) are involved in the regulation of LC20 phosphorylation and have important roles in modulating smooth muscle contractile responses to Ca2+ (i.e., Ca2+ sensitization and Ca2+ desensitization). Here, we review the general background and structure of ZIPK and summarize our current understanding of its involvement in a number of cell processes including cell death (apoptosis), cell motility, and smooth muscle contraction. ZIPK has been found to induce the diphosphorylation of LC20 at Ser-19 and Thr-18 in a Ca2+-independent manner and to regulate MLCP activity directly through its phosphorylation of the myosin-targeting subunit of MLCP or indirectly through its phosphorylation of the PKC-potentiated inhibitory protein of MLCP. Future investigations of ZIPK function in smooth muscle will undoubtably focus on determining the mechanisms that regulate its cellular activity, including the identification of upstream signaling pathways, the characterization of autoinhibitory domains and regulatory phosphorylation sites, and the development of specific inhibitor compounds.
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Affiliation(s)
- Eikichi Ihara
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, University of Calgary, Faculty of Medicine, 3330 Hospital Drive N.W, Calgary, AB T2N 4N1, Canada
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31
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Akata T. Cellular and molecular mechanisms regulating vascular tone. Part 2: regulatory mechanisms modulating Ca2+ mobilization and/or myofilament Ca2+ sensitivity in vascular smooth muscle cells. J Anesth 2007; 21:232-42. [PMID: 17458653 DOI: 10.1007/s00540-006-0488-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Accepted: 11/21/2006] [Indexed: 11/25/2022]
Abstract
Understanding the physiological mechanisms regulating vascular tone would lead to better circulatory management during general anesthesia. This two-part review provides an overview of current knowledge about the cellular and molecular mechanisms regulating the contractile state of vascular smooth muscle cells (i.e., vascular tone). The first part reviews basic mechanisms controlling the cytosolic Ca2+ concentration in vascular smooth muscle cells, and the Ca2+-dependent regulation of vascular tone. This second part reviews the regulatory mechanisms modulating Ca2+ mobilization and/or myofilament Ca2+ sensitivity in vascular smooth muscle cells-including Rho/Rho kinase, protein kinase C, arachidonic acid, Ca2+/calmodulin-dependent protein kinase II, caldesmon, calponin, mitogen-activated protein kinases, tyrosine kinases, cyclic nucleotides, Cl- channels, and K+ channels.
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Affiliation(s)
- Takashi Akata
- Department of Anesthesiology and Critical Care Medicine, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
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32
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Rosenthal R, Choritz L, Schlott S, Bechrakis NE, Jaroszewski J, Wiederholt M, Thieme H. Effects of ML-7 and Y-27632 on carbachol- and endothelin-1-induced contraction of bovine trabecular meshwork. Exp Eye Res 2005; 80:837-45. [PMID: 15939040 DOI: 10.1016/j.exer.2004.12.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Revised: 12/20/2004] [Accepted: 12/28/2004] [Indexed: 11/18/2022]
Abstract
The trabecular meshwork is considered a smooth muscle like tissue contributing to aqueous outflow regulation and thus to regulation of intraocular pressure. An elevation in intraocular pressure is one of the greatest risk factors for most forms of glaucoma. We assume that contraction of trabecular meshwork reduces aqueous humor outflow and thus enhances intraocular pressure, whereas relaxation exerts the opposite effect. The present paper supports the hypothesis of the trabecular meshwork being a smooth muscle-like tissue. We perform measurements of isometric force in isolated bovine trabecular meshwork strips. Contractility of this tissue is induced by carbachol or endothelin-1. The contractile force is successfully inhibited by ML-7, a highly specific inhibitor of myosin light chain kinase. The contraction is also reduced in the presence of the RhoA kinase inhibitor Y-27632. We further describe the protein expression of smooth muscle myosin and its regulatory kinase, the myosin light chain kinase, in human and bovine trabecular meshwork cells. Additionally, the serine phosphorylation of myosin light chain kinase is shown. These data indicate that the trabecular meshwork expresses major contractility regulating proteins which are involved in tissue function. Inhibition of the signaling pathways which lead to myosin phosphorylation causes inhibition of contractile force in trabecular meshwork. According to our concept of aqueous humor outflow regulation, trabecular meshwork relaxing substances appear to be ideal antiglaucomatous drugs, leading to increased outflow facility.
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Affiliation(s)
- Rita Rosenthal
- Augenklinik und Augenpoliklinik, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.
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33
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Schuster S, Knoke B, Marhl M. Differential regulation of proteins by bursting calcium oscillations--a theoretical study. Biosystems 2005; 81:49-63. [PMID: 15917128 DOI: 10.1016/j.biosystems.2005.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Accepted: 02/14/2005] [Indexed: 11/29/2022]
Abstract
Calcium in ionic form is a second messenger connecting several input signals to several target processes in the cell. The question arises how one second messenger can transmit more than one signal simultaneously (bow-tie structure of signalling). Experimental data on calcium dynamics often show patterns of successive low-peak and high-peak oscillatory phases, known as bursting. Here, we propose that bursting calcium oscillations can perform the function of simultaneous transmission of two signals at physiological calcium concentrations, for example, by selective activation of two calcium-binding proteins. This differential regulation by periodic bursting is investigated in a theoretical model. The two proteins are assumed to be activated by calcium, and one of them is assumed to be subject to biphasic regulation due to additional inhibitory binding sites. To explore which characteristics of the complex signal could be responsible for independent regulation of low-peak activated and spike activated targets, different bursting patterns of simplified square pulses are applied. Depending on the change in the bursting pattern, one protein can be gradually activated at a constant level of the other protein's activity, or the two proteins can be activated simultaneously, or one protein can be activated while the other one is deactivated simultaneously. Thus, the two proteins can be regulated virtually independently.
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Affiliation(s)
- Stefan Schuster
- Department of Bioinformatics, Faculty of Biology and Pharmaceutics, Friedrich-Schiller University of Jena, Ernst-Abbe-Platz 2, D-07743 Jena, Germany.
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34
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Lukas TJ. A signal transduction pathway model prototype II: Application to Ca2+-calmodulin signaling and myosin light chain phosphorylation. Biophys J 2005; 87:1417-25. [PMID: 15345524 PMCID: PMC1304550 DOI: 10.1529/biophysj.104.042721] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An agonist-initiated Ca(2+) signaling model for calmodulin (CaM) coupled to the phosphorylation of myosin light chains was created using a computer-assisted simulation environment. Calmodulin buffering was introduced as a module for directing sequestered CaM to myosin light chain kinase (MLCK) through Ca(2+)-dependent release from a buffering protein. Using differing simulation conditions, it was discovered that CaM buffering allowed transient production of more Ca(2+)-CaM-MLCK complex, resulting in elevated myosin light chain phosphorylation compared to nonbuffered control. Second messenger signaling also impacts myosin light chain phosphorylation through the regulation of myosin light chain phosphatase (MLCP). A model for MLCP regulation via its regulatory MYPT1 subunit and interaction of the CPI-17 inhibitor protein was assembled that incorporated several protein kinase subsystems including Rho-kinase, protein kinase C (PKC), and constitutive MYPT1 phosphorylation activities. The effects of the different routes of MLCP regulation depend upon the relative concentrations of MLCP compared to CPI-17, and the specific activities of protein kinases such as Rho and PKC. Phosphorylated CPI-17 (CPI-17P) was found to dynamically control activity during agonist stimulation, with the assumption that inhibition by CPI-17P (resulting from PKC activation) is faster than agonist-induced phosphorylation of MYPT1. Simulation results are in accord with literature measurements of MLCP and CPI-17 phosphorylation states during agonist stimulation, validating the predictive capabilities of the system.
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Affiliation(s)
- Thomas J Lukas
- Department of Molecular Pharmacology and Drug Discovery Program, Northwestern University, Chicago, Illinois 60611, USA.
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35
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Bennett MR, Farnell L, Gibson WG. A quantitative description of the contraction of blood vessels following the release of noradrenaline from sympathetic varicosities. J Theor Biol 2005; 234:107-22. [PMID: 15721040 DOI: 10.1016/j.jtbi.2004.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 10/23/2004] [Accepted: 11/11/2004] [Indexed: 11/24/2022]
Abstract
A model is presented that highlights the principal factors determining the form and extent of contraction in arteries upon stimulation of their sympathetic nerve supply. This model incorporates a previous quantitative model of the process of noradrenaline (NAd) diffusion into the vascular media and reuptake into sympathetic varicosities during nerve stimulation (J. Theor. Biol. 226 (2004) 359). It is also dependent on a model of how the subsequent activation of metabotropic receptors initiates a G-protein cascade, resulting in the production of inositol trisphosphate (IP3) and an increase in intracellular calcium concentration, [Ca2+]i, in the smooth muscle cells (J. Theor. Biol. 223 (2003) 93). In the present work we couple this rise in [Ca2+]i to the increase in phosphorylated myosin bound to actin in the cells and hence determine the force development in arteries due to nerve stimulation. The model accounts for force development as a function of [Ca2+]i and for the rate of change of force as a function of the rate of change of [Ca2+]i in single smooth muscle cells. It also accounts for the characteristic time course of the force developed by the media of the rat-tail artery upon nerve stimulation. This consists of a rapid rise to a transient peak followed by a sustained plateau of contraction during the stimulation period, after which the contraction slowly decays back to baseline at a rate dependent on the strength of the stimulation. The model indicates that the transient peak is primarily due to the partial block of the IP3 receptor by the rise in [Ca2+]i and that the main determinant of the equilibrium condition indicated by the plateau phase is the rate of pumping of calcium into the sarcoplasmic reticulum. The relatively slow decline of contraction at the end of nerve stimulation is primarily a consequence of the slow rates of removal of NAd from the media by diffusion and reuptake into the sympathetic varicosities. The model thus provides a quantitative account of vascular smooth muscle contraction upon sympathetic nerve stimulation.
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Affiliation(s)
- M R Bennett
- The Neurobiology Laboratory, Department of Physiology, and Institute for Biomedical Research, University of Sydney, NSW, 2006, Australia.
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36
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Bonnevier J, Arner A. Actions downstream of cyclic GMP/protein kinase G can reverse protein kinase C-mediated phosphorylation of CPI-17 and Ca²⁺ sensitization in smooth muscle. J Biol Chem 2004; 279:28998-9003. [PMID: 15123611 DOI: 10.1074/jbc.m404259200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ca(2+) sensitivity of smooth muscle contraction is modulated by several systems converging on myosin light chain phosphatase (MLCP). Rho-Rho kinase is considered to inhibit MLCP via phosphorylation, whereas protein kinase C (PKC) induced sensitization has been shown to be dependent on phosphorylation of the inhibitory protein CPI-17. We have explored the interaction of cGMP-dependent protein kinase (PKG) with Ca(2+) sensitization pathways using permeabilized mouse smooth muscle. Three conditions giving approximately 50% of maximal active force were compared in small intestinal preparations: 1). Ca(2+)-activated unsensitized muscle (pCa 5.9 with Rho kinase inhibitor Y27632); 2). Rho-Rho kinase-sensitized muscle (pCa 6.1 with guanosine 5'-3-O-(thio)triphosphate); and 3). PKC-sensitized muscle (pCa 6.0 with Y27632 and PKC activator phorbol 12,13-dibutyrate). 8-Br-cGMP relaxed the sensitized muscles but had marginal effects on unsensitized preparations, showing that PKG reverses both PKC and Rho-mediated Ca(2+) sensitization. CPI-17 was present in permeabilized intestinal tissue. In PKC-sensitized preparations, CPI-17 phosphorylation decreased in response to 8-Br-cGMP. The rate of PKC-mediated phosphorylation in the presence of the MLCP inhibitor microcystin-LR was not influenced by 8-Br-cGMP. PKC-induced Ca(2+) sensitization also was reversed in vascular smooth muscle tissues (portal vein and femoral artery). We conclude that actions downstream of cGMP/PKG can reverse PKC-mediated phosphorylation of CPI-17 and Ca(2+) sensitization in smooth muscle.
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Affiliation(s)
- Johan Bonnevier
- Department of Physiological Sciences, Lund University, SE-221 84 Lund, Sweden
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37
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Komatsu S, Miyazaki K, Tuft RA, Ikebe M. Translocation of telokin by cGMP signaling in smooth muscle cells. Am J Physiol Cell Physiol 2002; 283:C752-61. [PMID: 12176732 DOI: 10.1152/ajpcell.00501.2001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Telokin is an acidic protein with a sequence identical to the COOH-terminal domain of myosin light chain kinase (MLCK) produced by an alternate promoter of the MLCK gene. Although it is abundantly expressed in smooth muscle, its physiological function is not understood. In the present study, we attempted to clarify the function of telokin by analyzing its spatial and temporal localization in living single smooth muscle cells. Primary cultured smooth muscle cells were transfected with green fluorescent protein (GFP)-tagged telokin. The telokin-GFP localized mostly diffusely in cytosol. Stimulation with both sodium nitroprusside (SNP) and 8-bromo-cyclic GMP induced translocation of GFP-tagged telokin to near plasma membrane in living single smooth muscle cells. The translocation was slow, and it took more than 10 min at room temperature. Mutation of the phosphorylation sites of telokin (S13A, S19A, and S13A/S19A) significantly attenuated SNP-induced translocation. Both KT-5823 (cGMP-dependent protein kinase inhibitor) and PD-98059 (mitogen-activated protein kinase inhibitor) diminished the telokin-GFP translocation. These results suggest that telokin changes its intracellular localization because of phosphorylation at Ser13 and/or Ser19 via the cGMP-signaling pathway.
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Affiliation(s)
- Satoshi Komatsu
- Department of Physiology, University of Massachusetts Medical School, Worcester 01655, USA
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38
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Hidalgo C, Craig R, Ikebe M, Padrón R. Mechanism of phosphorylation of the regulatory light chain of myosin from tarantula striated muscle. J Muscle Res Cell Motil 2002; 22:51-9. [PMID: 11563549 DOI: 10.1023/a:1010388103354] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Contraction is modulated in many striated muscles by Ca2+-calmodulin dependent phosphorylation of the myosin regulatory light chain (RLC) by myosin light chain kinase. We have investigated the biochemical mechanism of RLC phosphorylation in tarantula muscle to better understand the basis of myosin-linked regulation. In an earlier study it was concluded that the RLC occurred as two species, both of which could be phosphorylated, potentiating contraction. Here we present evidence that only a single species exists, and that this can be phosphorylated at one or two sites. In relaxed muscle we find evidence for a substantial level of basal phosphorylation at the first site. This is augmented on activation, followed by partial phosphorylation of the second site. We find in addition that Ca2+ has a dual effect on light chain phosphorylation, depending on its concentration. At low concentration (relaxing conditions) only basal phosphorylation is observed, while at higher concentrations (activating conditions) RLC phosphorylation is stimulated. At still higher Ca2+ concentrations we find partial inhibition of RLC phosphorylation, suggesting an additional mechanism by which the muscle cell can fine tune contractile activity by controlling the level of free Ca2+.
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Affiliation(s)
- C Hidalgo
- Departamento de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas.
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39
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CLCA adhesion in site-specific cancer metastasis. CURRENT TOPICS IN MEMBRANES 2002. [DOI: 10.1016/s1063-5823(02)53044-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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40
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Alexanian AR, Bamburg JR, Hidaka H, Mornet D. Calcium-dependent regulation of interactions of caldesmon with calcium-binding proteins found in growth cones of chick forebrain neurons. Cell Mol Neurobiol 2001; 21:437-51. [PMID: 11860183 DOI: 10.1023/a:1013885404738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. This study was undertaken to determine if caldesmon, calmodulin, S100beta, and neurocalcin delta were present in chick forebrain neurons, and if so, to investigate the interactions of these proteins in the presence of different concentrations of calcium. 2. Immunocytochemistry was used to determine the presence and localization of these proteins in cultured forebrain neurons. Western blotting, gel electrophoresis in the presence of different concentrations of calcium, chemical cross-linking, and affinity chromatography were used to investigate the interactions of these proteins with each other. 3. Our data show that caldesmon and three calcium-binding proteins (S100beta, calmodulin, and neurocalcin 3) are localized in growth cones and neurites of chick forebrain neurons in culture. In the presence of different concentration of calcium, these calcium-binding proteins have different affinities to caldesmon and to each other. S100beta binds with greater affinity than calmodulin to caldesmon, and its ability to bind to caldesmon is regulated by neurocalcin delta. 4. These findings suggest a specific calcium-dependent regulatory pathway for modulating actomyosin during growth cone motility.
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Affiliation(s)
- A R Alexanian
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, USA.
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41
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Affiliation(s)
- J B Shabb
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9037, USA.
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42
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Piekny AJ, Wissmann A, Mains PE. Embryonic morphogenesis in Caenorhabditis elegans integrates the activity of LET-502 Rho-binding kinase, MEL-11 myosin phosphatase, DAF-2 insulin receptor and FEM-2 PP2c phosphatase. Genetics 2000; 156:1671-89. [PMID: 11102366 PMCID: PMC1461351 DOI: 10.1093/genetics/156.4.1671] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
let-502 rho-binding kinase and mel-11 myosin phosphatase regulate Caenorhabditis elegans embryonic morphogenesis. Genetic analysis presented here establishes the following modes of let-502 action: (i) loss of only maternal let-502 results in abnormal early cleavages, (ii) loss of both zygotic and maternal let-502 causes elongation defects, and (iii) loss of only zygotic let-502 results in sterility. The morphogenetic function of let-502 and mel-11 is apparently redundant with another pathway since elimination of these two genes resulted in progeny that underwent near-normal elongation. Triple mutant analysis indicated that unc-73 (Rho/Rac guanine exchange factor) and mlc-4 (myosin light chain) act in parallel to or downstream of let-502/mel-11. In contrast mig-2 (Rho/Rac), daf-2 (insulin receptor), and age-1 (PI3 kinase) act within the let-502/mel-11 pathway. Mutations in the sex-determination gene fem-2, which encodes a PP2c phosphatase (unrelated to the MEL-11 phosphatase), enhanced mutations of let-502 and suppressed those of mel-11. fem-2's elongation function appears to be independent of its role in sexual identity since the sex-determination genes fem-1, fem-3, tra-1, and tra-3 had no effect on mel-11 or let-502. By itself, fem-2 affects morphogenesis with low penetrance. fem-2 blocked the near-normal elongation of let-502; mel-11 indicating that fem-2 acts in a parallel elongation pathway. The action of two redundant pathways likely ensures accurate elongation of the C. elegans embryo.
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Affiliation(s)
- A J Piekny
- Genes & Development Research Group and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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43
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Kim I, Je HD, Gallant C, Zhan Q, Riper DV, Badwey JA, Singer HA, Morgan KG. Ca2+-calmodulin-dependent protein kinase II-dependent activation of contractility in ferret aorta. J Physiol 2000; 526 Pt 2:367-74. [PMID: 10896725 PMCID: PMC2270028 DOI: 10.1111/j.1469-7793.2000.00367.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. The present study was undertaken to determine whether Ca2+-calmodulin-dependent protein kinase II (CaMKII) participates in the regulation of vascular smooth muscle contraction, and if so, to investigate the nature of the downstream effectors. 2. The contractility of isolated ferret aorta was measured while inhibiting CaMKII either with antisense oligodeoxynucleotides against CaMKII or with the CaMKII inhibitor KN93. 3. Treatment with antisense oligodeoxynucleotides against CaMKII resulted in, on average, a decrease in protein levels of CaMKII to 56 % of control levels and significantly decreased the magnitude of the contraction in response to 51 mM potassium physiological saline solution (KCl). Contraction in response to the phorbol ester DPBA was not significantly affected. 4. The CaMKII blocker KN93 also resulted in a significant decrease in the force induced by 51 mM KCl but caused no significant change in the contraction in response to DPBA or the alpha-adrenoceptor agonist phenylephrine. 5. During contraction with 51 mM KCl, both CaMKII and mitogen-activated protein kinase (MAPK) activity increased, as determined by phospho-specific antibodies. The MAPK phosphorylation level was inhibited by KN93, PD098059 (a MAPK kinase (MEK) inhibitor) and calcium depletion. 6. Myosin light chain (LC20) phosphorylation also increased during contraction with KCl and the increase was significantly blocked by PD098059 as well as by both KN93 and antisense oligodeoxynucleotides to CaMKII. 7. The data indicate that CaMKII plays a significant role in the regulation of smooth muscle contraction and suggest that CaMKII activates a pathway by which MAPK activation leads to phosphorylation of LC20 via activation of myosin light chain kinase.
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Affiliation(s)
- I Kim
- Boston Biomedical Research Institute, Watertown, MA 02472, USA
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44
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Nguyen DH, Catling AD, Webb DJ, Sankovic M, Walker LA, Somlyo AV, Weber MJ, Gonias SL. Myosin light chain kinase functions downstream of Ras/ERK to promote migration of urokinase-type plasminogen activator-stimulated cells in an integrin-selective manner. J Cell Biol 1999; 146:149-64. [PMID: 10402467 PMCID: PMC2199739 DOI: 10.1083/jcb.146.1.149] [Citation(s) in RCA: 252] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/1998] [Accepted: 06/08/1999] [Indexed: 12/24/2022] Open
Abstract
Urokinase-type plasminogen activator (uPA) activates the mitogen activated protein (MAP) kinases, extracellular signal-regulated kinase (ERK) 1 and 2, in diverse cell types. In this study, we demonstrate that uPA stimulates migration of MCF-7 breast cancer cells, HT 1080 fibrosarcoma cells, and uPAR-overexpressing MCF-7 cells by a mechanism that depends on uPA receptor (uPAR)-ligation and ERK activation. Ras and MAP kinase kinase (MEK) were necessary and sufficient for uPA-induced ERK activation and stimulation of cellular migration, as demonstrated in experiments with dominant-negative and constitutively active mutants of these signaling proteins. Myosin light chain kinase (MLCK) was also required for uPA-stimulated cellular migration, as determined in experiments with three separate MLCK inhibitors. When MCF-7 cells were treated with uPA, MLCK was phosphorylated by a MEK-dependent pathway and apparently activated, since serine-phosphorylation of myosin II regulatory light chain (RLC) was also increased. Despite the transient nature of ERK phosphorylation, MLCK remained phosphorylated for at least 6 h. The uPA-induced increase in MCF-7 cell migration was observed selectively on vitronectin-coated surfaces and was mediated by a beta1-integrin (probably alphaVbeta1) and alphaVbeta5. When MCF-7 cells were transfected to express alphaVbeta3 and treated with uPA, ERK was still phosphorylated; however, the cells did not demonstrate increased migration. Neutralizing the function of alphaVbeta3, with blocking antibody, restored the ability of uPA to promote cellular migration. Thus, we have demonstrated that uPA promotes cellular migration, in an integrin-selective manner, by initiating a uPAR-dependent signaling cascade in which Ras, MEK, ERK, and MLCK serve as essential downstream effectors.
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Affiliation(s)
- Diem H.D. Nguyen
- Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Andrew D. Catling
- Department of Microbiology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Donna J. Webb
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Mauricio Sankovic
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Lori A. Walker
- Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Avril V. Somlyo
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
- Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Michael J. Weber
- Department of Microbiology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Steven L. Gonias
- Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
- Department of Pathology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
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45
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Garcia JG, Verin AD, Schaphorst K, Siddiqui R, Patterson CE, Csortos C, Natarajan V. Regulation of endothelial cell myosin light chain kinase by Rho, cortactin, and p60(src). THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:L989-98. [PMID: 10362724 DOI: 10.1152/ajplung.1999.276.6.l989] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inflammatory diseases of the lung are characterized by increases in vascular permeability and enhanced leukocyte infiltration, reflecting compromise of the endothelial cell (EC) barrier. We examined potential molecular mechanisms that underlie these alterations and assessed the effects of diperoxovanadate (DPV), a potent tyrosine kinase activator and phosphatase inhibitor, on EC contractile events. Confocal immunofluorescent microscopy confirmed dramatic increases in stress-fiber formation and colocalization of EC myosin light chain (MLC) kinase (MLCK) with the actin cytoskeleton, findings consistent with activation of the endothelial contractile apparatus. DPV produced significant time-dependent increases in MLC phosphorylation that were significantly attenuated but not abolished by EC MLCK inhibition with KT-5926. Pretreatment with the Rho GTPase-inhibitory C3 exotoxin completely abolished DPV-induced MLC phosphorylation, consistent with Rho-mediated MLC phosphatase inhibition and novel regulation of EC MLCK activity. Immunoprecipitation of EC MLCK after DPV challenge revealed dramatic time-dependent tyrosine phosphorylation of the kinase in association with increased MLCK activity and a stable association of MLCK with the p85 actin-binding protein cortactin and p60(src). Translocation of immunoreactive cortactin from the cytosol to the cytoskeleton was noted after DPV in concert with cortactin tyrosine phosphorylation. These studies indicate that DPV activates the endothelial contractile apparatus in a Rho GTPase-dependent fashion and suggests that p60(src)-induced tyrosine phosphorylation of MLCK and cortactin may be important features of contractile complex assembly.
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Affiliation(s)
- J G Garcia
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA.
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46
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Wu X, Haystead TA, Nakamoto RK, Somlyo AV, Somlyo AP. Acceleration of myosin light chain dephosphorylation and relaxation of smooth muscle by telokin. Synergism with cyclic nucleotide-activated kinase. J Biol Chem 1998; 273:11362-9. [PMID: 9556631 DOI: 10.1074/jbc.273.18.11362] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Incorporation of 32P into telokin, a smooth muscle-specific, 17-18-kDa, acidic (pI 4.2-4.4) protein, was increased by forskolin (20 microM) in intact rabbit ileum smooth muscle (ileum) and by 8-bromo-cyclic GMP (100 microM) in alpha-toxin-permeabilized ileum. Native telokin (5-20 microM), purified from turkey gizzard, and recombinant rabbit telokin, expressed in Escherichia coli and purified to >90% purity, induced dose-dependent relaxation, associated with a significant decrease in regulatory myosin light chain phosphorylation, without affecting the rate of thiophosphorylation of regulatory myosin light chain of ileum permeabilized with 0.1% Triton X-100. Endogenous telokin was lost from ileum during prolonged permeabilization (>20 min) with 0.1% Triton X-100, and the time course of loss was correlated with the loss of 8-bromo-cyclic GMP-induced calcium desensitization. Recombinant and native gizzard telokins were phosphorylated, in vitro, by the catalytic subunit of cAMP-dependent protein kinase, cGMP-dependent protein kinase, and p42/44 mitogen-activated protein kinase; the recombinant protein was also phosphorylated by calmodulin-dependent protein kinase II. Exogenous cGMP-dependent protein kinase (0.5 microM) activated by 8-bromo-cyclic GMP (50 microM) phosphorylated recombinant telokin (10 microM) when added concurrently to ileum depleted of its endogenous telokin, and their relaxant effects were mutually potentiated. Forskolin (20 microM) also increased phosphorylation of telokin in intact ileum. We conclude that telokin induces calcium desensitization in smooth muscle by enhancing myosin light chain phosphatase activity, and cGMP- and/or cAMP-dependent phosphorylation of telokin up-regulates its relaxant effect.
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Affiliation(s)
- X Wu
- Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22906-0011, USA
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47
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Miralem T, Templeton DM. Heparin inhibits Ca2+/calmodulin-dependent kinase II activation and c-fos induction in mesangial cells. Biochem J 1998; 330 ( Pt 2):651-7. [PMID: 9480871 PMCID: PMC1219186 DOI: 10.1042/bj3300651] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Like vascular smooth-muscle cells, rat mesangial cells (RMCs) display an anti-mitogenic response to heparin. In particular, heparin partially suppresses the ability of quiescent RMCs to enter the cell cycle and induce c-fos expression. When the mitogenic stimulus is serum, phorbol ester or platelet-derived growth factor, this response appears to result from the ability of heparin to suppress activation of the extracellular-signal-regulated kinase family of mitogen-activated protein kinases. However, we have also shown that heparin suppresses c-fos expression in response to ionophores such as ionomycin, an event independent of mitogen-activated protein kinase [Miralem, Wang, Whiteside and Templeton (1996) J. Biol. Chem. 271, 17100-17106]. Here we identify this second heparin-sensitive pathway as involving Ca2+/calmodulin-dependent kinase (CaMK) II. Ionomycin (100 nM) caused a transient rise in intracellular Ca2+ concentration ([Ca2+]i) in quiescent RMCs to 386+/-55 nM, with an increase in CaMK II activity that peaked 30 s later. The accumulation of c-fos mRNA that ensued 30 min later was prevented when the increase in [Ca2+]i was prevented with the intracellular Ca2+ chelator, 1,2-bis-(2-aminophenyoxy)ethane-N,N,N',N'-tetra-acetic acid. The broad-specificity CaMK inhibitor, KT 5926, inhibited ionomycin-dependent c-fos induction at a concentration at which it was without effect on induction by serum or phorbol ester. The CaMK II-specific inhibitor, KN-93, likewise inhibited c-fos induction by ionomycin, but not by serum or phorbol ester. ML-7, an inhibitor of the CaMK-related myosin light-chain kinase (MLCK), was without effect. Heparin (1 microg/ml) suppressed ionomycin-dependent c-fos induction. It was without effect on [Ca2+]i, but inhibited the development of autonomous CaMK II activity. However, when heparin was added to the CaMK II assay solution in vitro, it was without effect on autonomous activity. Furthermore, heparin did not prevent full activation of CaMK II by the Ca2+-calmodulin complex in vitro. Heparin did not affect myosin light-chain phosphorylation or RMC contraction, processes mediated by MLCK. We conclude that ionomycin induces c-fos in RMCs through the CaMK II pathway, and that heparin prevents CaMK II activation by an indirect process mediated by other cell components. Heparin does not affect activation of the closely related CaMK, MLCK.
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Affiliation(s)
- T Miralem
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
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48
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Babiychuk EB, Sobieszek A. Oligomerization of smooth muscle myosin light chain kinase and its modifications by melittin and calmodulin. Biopolymers 1997; 42:673-86. [PMID: 9358732 DOI: 10.1002/(sici)1097-0282(199711)42:6<673::aid-bip6>3.0.co;2-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The catalytic activity of smooth muscle myosin light chain kinase (MLCKase) requires the presence of calcium and calmodulin [CM; J. T. Stull et al. (1993) Molecular and Cellular Biochemistry, Vols. 127/128, pp. 229-237] and can also be modified through its own oligomerization [E. B. Babiychuk et al. (1995) Biochemistry, Vol. 34, pp. 6366-6372]. In the present report we demonstrate that melittin, one of the most potent CM antagonists, interacted reversibly with the MLCKase apoenzyme with affinities comparable to those of CM and influenced the oligomeric state of the kinase. At low melittin to kinase ratios the kinase formed insoluble oligomers (aggregates) while at higher melittin concentrations it existed predominantly as soluble oligomers revealed by cross-linking as octamers and hexamers. The kinase alone exhibited similar biphasic solubility within a 5-30 microM range and its solubility was strongly influenced by the ionic strength of the medium. Melittin was also found to promote both the aggregation of the purified 24-kDa C-terminal fragment of the kinase and its analogue telokin, as well as of myosin light chains, but had no effect on the solubility of bovine serum albumin, caldesmon, or calmodulin. These data and our cross-linkage experiments indicate that the insoluble kinase oligomers arose via melittin-induced aggregation of the kinase dimers in which the relokin-like domain played a main role. The soluble oligomers, in turn, were formed after saturation of the kinase with melittin, which resulted in a weakening of the interaction between the protomers with an increase of the long-range order within the oligomers. This interpretation is consistent with the observed effects of melittin on MLCKase catalytic and autocatalytic activities. At concentrations of melittin required to produce soluble oligomers, the binding of the kinase to myosin filaments was considerably enhanced. A plausible mechanism for the formation of the soluble oligomers and aggregates is suggested and its relation to the possible MLCKase assemblies discussed in terms of a model.
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Affiliation(s)
- E B Babiychuk
- Institute of Molecular Biology, Austrian Academy of Sciences, Salzburg, Austria
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49
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Filenko AM, Danilova VM, Sobieszek A. Smooth muscle myosin light chain kinase, supramolecular organization, modulation of activity, and related conformational changes. Biophys J 1997; 73:1593-606. [PMID: 9284326 PMCID: PMC1181058 DOI: 10.1016/s0006-3495(97)78191-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It has recently been suggested that activation of smooth muscle myosin light chain kinase (MLCK) can be modulated by formation of supramolecular structures (Sobieszek, A. 1991. Regulation of smooth muscle myosin light chain kinase. Allosteric effects and co-operative activation by CaM. J. Mol. Biol. 220:947-957). The present light scattering data demonstrate that the inactive (calmodulin-free) MLCK apoenzyme exists in solution as a mixture of oligomeric (2% by weight), dimeric (53%), and monomeric (45%) species at physiological ionic strength (160 mM salt). These long-living assemblies, the lifetime of which was measured by minutes, were in equilibrium with each other. The most likely form of the oligomer was a spiral-like hexamer, the dimensions of which fit very well the helical structure of self-assembled myosin filaments (Sobieszek, A. 1972. Cross-bridges on self-assembled smooth muscle myosin filaments. J. Mol. Biol. 70:741-744). After activation of the kinase by calmodulin (CaM) we could not detect any appreciable changes in the distribution of the kinase species either when the kinase was saturated with CaM or when its molar concentration exceeded that of CaM. Our fluorescent measurements suggest that the earlier observed inhibition of kinase at substoichiometric amounts of CaM (Sobieszek, A., A. Strobl, B. Ortner, and E. Babiychuk. 1993. Ca2+-calmodulin-dependent modification of smooth-muscle myosin light chain kinase leading to its co-operative activation by calmodulin. Biochem. J. 295:405-411) is associated with slow conformational change(s) of the activated (CaM-bound) kinase molecules. Such conformational rearrangements also took place with equimolar kinase to CaM; however, in this case there was no decrease in MLCK activity. The nature of these conformational changes, which are accompanied by reduction of the kinase for CaM affinity, is discussed.
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Affiliation(s)
- A M Filenko
- Institute of Physiology, Taras Shevchenko Kiev University, Ukraine
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50
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Zhou X, Li C, Dlugosz J, Kapor-Drezgic J, Munk S, Whiteside C. Mesangial cell actin disassembly in high glucose mediated by protein kinase C and the polyol pathway. Kidney Int 1997; 51:1797-808. [PMID: 9186869 DOI: 10.1038/ki.1997.247] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
High glucose alters mesangial cell cytoskeletal structure and function. We postulated that high glucose causes mesangial cell filamentous (F) actin disassembly through a protein kinase C (PKC) mechanism involving the polyol pathway. Rat mesangial cells (passage < 10, N = 60/group) were growth-arrested and then cultured in glucose 5.6 mM (NG), 15 mM (MG) or 30 mM (HG) for 48 hours, with or without the aldose reductase inhibitor Tolrestat 0.3 mM. F and globular (G) actin were labeled with rhodamine-phalloidin and FTTC-DNase-1, respectively. Both fluorescence probes were imaged simultaneously in each cell using dual-channel confocal laser microscopy. In HG, F-actin disassembly was observed and measured by a 40% decrease in F-/G-actin fluorescence intensity ratio (no change in NG + mannitol 24.4 mM). In separate experiments, cells were labeled with BODIPY FL-bisindolylmaleimide, specific for most PKC isoforms, and fluorescence intensity/cell was measured. In NG, exposure to phorbol 12-myristate 13-acetate (PMA) 0.1 microM for 15 minutes caused perinuclear and nuclear translocation of PKC, and F-actin disassembly identical to observations in HG alone. In HG, total PKC fluorescence increased by 50% and PMA exposure for 24 hours normalized both the total PKC and F-/G-actin fluorescence ratio. In NG and HG, exposure (15 min) to PMA 0.1 microM increased PKC activity three to four times, measured by in situ 32P-phosphorylation of EGF-receptor substrate. By immunofluorescence and confocal imaging, diacylglycerol-sensitive PKC-delta was localized to the cytosol in NG, and after 15 minutes exposure to PMA, translocated to the perinuclear region and plasma membrane. In HG. PKC-delta immunofluorescence was significantly increased/cell, distributed in a cytoskeletal pattern and the intensity was glucose-concentration dependent (30 > 15 > 5.6 mM). In HG, exposure to PMA for 24 hours returned the PKC-delta fluorescence to the intensity and cytosolic pattern observed in NG, and simultaneously prevented F-actin disassembly. Tolrestat significantly reduced the total PKC and PKC-delta fluorescence intensity and F-actin disassembly observed in HG. Immunoblot confirmed increased PKC-delta in HG, which was normalized by Tolrestat. The immunofluorescence pattern of diacylglycerol-insensitive PKC-delta was unchanged in HG, with PMA or Tolrestat. We conclude that mesangial cell F-actin disassembly in high glucose is likely mediated through diacylglycerol-sensitive PKC isoforms, including PKC-delta and involves the polyol pathway.
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Affiliation(s)
- X Zhou
- Department of Medicine, University of Toronto, Ontario, Canada
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