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Liang Y, Li L, Chen Y, Zhang S, Li Z, Xiao J, Wei D. Research Progress on the Role of Intermediate Filament Vimentin in Atherosclerosis. DNA Cell Biol 2021; 40:1495-1502. [PMID: 34931866 DOI: 10.1089/dna.2021.0623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The cytoskeleton is a biopolymer network composed of intermediate filaments, actin, and microtubules, which is the main mechanical structure of cells. Vimentin is an intermediate filament protein that regulates the mechanical and contractile properties of cells, thereby reflecting their mechanical properties. In recent years, the "nonmechanical function" of vimentin inside and outside of cells has attracted extensive attention. The content of vimentin in atherosclerotic plaques is increased, and the serum secretion of vimentin in patients with coronary heart disease is remarkably increased. In this review, the mechanistic and nonmechanistic roles of vimentin in atherosclerosis progression were summarized on the basis of current studies.
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Affiliation(s)
- Yamin Liang
- Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Institute of Cardiovascular Disease, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Lu Li
- Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Institute of Cardiovascular Disease, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Yanmei Chen
- Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Institute of Cardiovascular Disease, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Shulei Zhang
- Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Institute of Cardiovascular Disease, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Zhaozhi Li
- Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Institute of Cardiovascular Disease, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Jinyan Xiao
- YueYang Maternal-Child Medicine Health Hospital Hunan Province Innovative Training Base for Medical Postgraduates, University of China South China and Yueyang Women and Children's Medical Center, Yueyang, Hunan, China
| | - Dangheng Wei
- Key Laboratory for Arteriosclerology of Hunan Province, Hunan International Scientific and Technological Cooperation Base of Arteriosclerotic Disease, Institute of Cardiovascular Disease, Hengyang Medical College, University of South China, Hengyang, Hunan, China
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2
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Src and SHP2 coordinately regulate the dynamics and organization of vimentin filaments during cell migration. Oncogene 2019; 38:4075-4094. [PMID: 30696956 PMCID: PMC6755999 DOI: 10.1038/s41388-019-0705-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 11/28/2018] [Accepted: 01/04/2019] [Indexed: 12/27/2022]
Abstract
Vimentin intermediate filaments (VIFs), expressed in most mesenchymal and cancer cells, undergo dramatic reorganization during cell migration; however, the mechanism remains obscure. This study demonstrates that upon growth-factor stimulation, Src directly phosphorylates vimentin at Tyr117, leading to VIF disassembly into squiggles and particles at the cell edge during lamellipodia formation. The protein tyrosine phosphatase SHP2 counteracted the Src effects on VIF tyrosine phosphorylation and organization. VIFs formed by vimentin Y117D mutant were more soluble and dynamic than those formed by the wild-type and Y117F mutant. Increased expression of vimentin promoted growth-factor induced lamellipodia formation and cell migration, whereas the mutants suppressed both. The vimentin-induced increase in lamellipodia formation correlated with the activation of Rac and Vav2, with the latter associated with VIFs and recruited to the plasma membrane upon growth-factor stimulation. These results reveal a novel mechanism for regulating VIF dynamics through Src and SHP2 and demonstrate that proper VIF dynamics are important for Rac activation and cell migration.
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3
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Satelli A, Li S. Vimentin in cancer and its potential as a molecular target for cancer therapy. Cell Mol Life Sci 2011; 68:3033-46. [PMID: 21637948 PMCID: PMC3162105 DOI: 10.1007/s00018-011-0735-1] [Citation(s) in RCA: 1054] [Impact Index Per Article: 81.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/12/2011] [Accepted: 05/16/2011] [Indexed: 02/06/2023]
Abstract
Vimentin, a major constituent of the intermediate filament family of proteins, is ubiquitously expressed in normal mesenchymal cells and is known to maintain cellular integrity and provide resistance against stress. Vimentin is overexpressed in various epithelial cancers, including prostate cancer, gastrointestinal tumors, tumors of the central nervous system, breast cancer, malignant melanoma, and lung cancer. Vimentin's overexpression in cancer correlates well with accelerated tumor growth, invasion, and poor prognosis; however, the role of vimentin in cancer progression remains obscure. In recent years, vimentin has been recognized as a marker for epithelial-mesenchymal transition (EMT). Although EMT is associated with several tumorigenic events, vimentin's role in the underlying events mediating these processes remains unknown. By virtue of its overexpression in cancer and its association with tumor growth and metastasis, vimentin serves as an attractive potential target for cancer therapy; however, more research would be crucial to evaluate its specific role in cancer. Our recent discovery of a vimentin-binding mini-peptide has generated further impetus for vimentin-targeted tumor-specific therapy. Furthermore, research directed toward elucidating the role of vimentin in various signaling pathways would reveal new approaches for the development of therapeutic agents. This review summarizes the expression and functions of vimentin in various types of cancer and suggests some directions toward future cancer therapy utilizing vimentin as a potential molecular target.
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Affiliation(s)
- Arun Satelli
- Department of Pediatrics, Unit 853, The University of Texas MD Anderson Cancer Center, 1515 Holocombe Blvd, Houston, TX 77030 USA
| | - Shulin Li
- Department of Pediatrics, Unit 853, The University of Texas MD Anderson Cancer Center, 1515 Holocombe Blvd, Houston, TX 77030 USA
- UTMD, Graduate School of Biomedical Science, Houston, TX 77030 USA
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4
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Thakkar D, Shervington L, Shervington A. Proteomic studies coupled with RNAi methodologies can shed further light on the downstream effects of telomerase in glioma. Cancer Invest 2011; 29:113-22. [PMID: 21261472 DOI: 10.3109/07357907.2010.543212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A comprehensive proteomic study utilizing 2D-DIGE and MALDI-TOF was used to assess the effect of inhibiting two different regulatory mechanisms of telomerase in glioma. RNAi was used to target hTERT and hsp90α. Inhibition of telomerase activity resulted in downregulation of various cytoskeletal proteins with correlative evidence of the involvement of telomerase in regulating the expression of vimentin. Inhibition of telomerase via sihTERT resulted in the downregulation of vimentin expression in glioma cell lines in a grade-specific manner. This study identified novel downstream role of telomerase in regulating the expression of vimentin, thereby affecting tumor progression and metastasis.
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Affiliation(s)
- Dipti Thakkar
- Brain Tumour North West, Faculty of Science and Technology, University of Central Lancashire, Preston, UK
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5
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Bouamrani A, Ramus C, Gay E, Pelletier L, Cubizolles M, Brugière S, Wion D, Berger F, Issartel JP. Increased phosphorylation of vimentin in noninfiltrative meningiomas. PLoS One 2010; 5:e9238. [PMID: 20169076 PMCID: PMC2821924 DOI: 10.1371/journal.pone.0009238] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 01/24/2010] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Tissue invasion or tissue infiltration are clinical behaviors of a poor-prognosis subset of meningiomas. We carried out proteomic analyses of tissue extracts to discover new markers to accurately distinguish between infiltrative and noninfiltrative meningiomas. METHODOLOGY/PRINCIPAL FINDINGS Protein lysates of 64 different tissue samples (including two brain-invasive and 32 infiltrative tumors) were submitted to SELDI-TOF mass spectrometric analysis. Mass profiles were used to build up both unsupervised and supervised hierarchical clustering. One marker was found at high levels in noninvasive and noninfiltrative tumors and appeared to be a discriminative marker for clustering infiltrative and/or invasive meningiomas versus noninvasive meningiomas in two distinct subsets. Sensitivity and specificity were 86.7% and 100%, respectively. This marker was purified and identified as a multiphosphorylated form of vimentin, a cytoskeletal protein expressed in meningiomas. CONCLUSIONS/SIGNIFICANCE Specific forms of vimentin can be surrogate molecular indicators of the invasive/infiltrative phenotype in tumors.
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Affiliation(s)
- Ali Bouamrani
- Grenoble Institut des Neurosciences, INSERM U836, Université Joseph Fourier, Grenoble, France
| | - Claire Ramus
- Grenoble Institut des Neurosciences, INSERM U836, Université Joseph Fourier, Grenoble, France
| | - Emmanuel Gay
- Department of Neurosurgery and Pathology, Centre Hospitalier Universitaire, Grenoble, France
| | - Laurent Pelletier
- Grenoble Institut des Neurosciences, INSERM U836, Université Joseph Fourier, Grenoble, France
| | | | | | - Didier Wion
- Grenoble Institut des Neurosciences, INSERM U836, Université Joseph Fourier, Grenoble, France
| | - François Berger
- Grenoble Institut des Neurosciences, INSERM U836, Université Joseph Fourier, Grenoble, France
| | - Jean-Paul Issartel
- Grenoble Institut des Neurosciences, INSERM U836, Université Joseph Fourier, Grenoble, France
- Centre National de la Recherche Scientifique (CNRS), Grenoble, France
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6
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Huang SY, Tsai ML, Chen GY, Wu CJ, Chen SH. A Systematic MS-Based Approach for IdentifyinginvitroSubstrates of PKA and PKG in Rat Uteri. J Proteome Res 2007; 6:2674-84. [PMID: 17564427 DOI: 10.1021/pr070134c] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein phosphorylation is an important modulator of many cellular processes, and identification of kinase substrates provides critical insights for signal transduction. However, this identification process is often difficult and many kinase substrates remain unexplored. Herein, a systematic proteomics approach solely depending on MS detection is reported for identifying substrates of PKA and PKG, which are suspected to have similar specificity determinants, in pregnant rat uteri. Instead of radioisotopes that are commonly used to couple with MS for substrate identification, this study developed an efficient in vitro kinase assay on depleted tissue homogenates to reveal substrate candidates directly by MS. To facilitate MS detection, exogenous phosphatases were added to remove intrinsic phosphorylation followed by a heating step to inactivate all enzymes. No observable interference caused by endogenous kinases or background phosphorylation was detected in the control experiment in which no kinase was externally added. A total of 61 and 12 substrate candidates were identified in vitro for PKA and PKG, respectively, and most of these identified sites contain consensus motifs of each kinase with only a few sites overlapped, indicating a good specificity. Moreover, differential phosphoproteomics analysis using stable isotope dimethyl labeling and MS was performed to detect the change of protein phosphorylation upon kinase stimulation in vivo. Four identified in vitro PKA substrates including three reported sites on HSP27 or filamin A were significantly phosphorylated in vivo, giving them high confidence as physiological substrates in pregnant rat uteri. Moreover, telokin, a known PKG substrate on S1880, and actin-binding proteins such as Arp 3, titin, and desmuslin were also identified to be in vitro PKG substrates in pregnant rat uteri. These proteins are all expected to be involved in the regulation of actin-mediated cytoskeletal remodeling.
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Affiliation(s)
- Sheng-Yu Huang
- Department of Chemistry, National Cheng Kung University, No.1, Ta-Hsueh Road, Tainan, 701, Taiwan
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7
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Zamoner A, Corbelini PF, Funchal C, Menegaz D, Silva FRMB, Pessoa-Pureur R. Involvement of calcium-dependent mechanisms in T3-induced phosphorylation of vimentin of immature rat testis. Life Sci 2005; 77:3321-35. [PMID: 15985269 DOI: 10.1016/j.lfs.2005.05.042] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Accepted: 05/09/2005] [Indexed: 11/29/2022]
Abstract
Thyroid hormones have been shown to act at extra nuclear sites, inducing target cell responses by several mechanisms, frequently involving intracellular calcium concentration. It has also been reported that cytoskeletal proteins are a target for thyroid and steroid hormones and cytoskeletal rearrangements are observed during hormone-induced differentiation and development of rat testes. However, little is known about the effect of 3,5,3'-triiodo-L-thyronine (T3) on the intermediate filament (IF) vimentin in rat testes. In this study we investigated the immunocontent and in vitro phosphorylation of vimentin in the cytoskeletal fraction of immature rat testes after a short-term in vitro treatment with T3. Gonads were incubated with or without T3 and 32P orthophosphate for 30 min and the intermediate filament-enriched cytoskeletal fraction was extracted in a high salt Triton-containing buffer. Vimentin immunoreactivity was analyzed by immunoblotting and the in vitro 32P incorporation into this protein was measured. Results showed that 1 microM T3 was able to increase the vimentin immunoreactivity and in vitro phosphorylation in the cytoskeletal fraction without altering total vimentin immunocontent in immature rat testes. Besides, these effects were independent of active protein synthesis. The involvement of Ca2+-mediated mechanisms in vimentin phosphorylation was evident when specific channel blockers (verapamil and nifedipine) or chelating agents (EGTA and BAPTA) were added during pre-incubation and incubation of the testes with T3. The effect of T3 was prevented when Ca2+ influx was blocked or intracellular Ca2+ was chelated. These results demonstrate a rapid nongenomic Ca2+-dependent action of T3 in phosphorylating vimentin in immature rat testes.
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Affiliation(s)
- Ariane Zamoner
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600 anexo CEP 90035-003 Porto Alegre RS Brazil
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8
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Ermakova S, Choi BY, Choi HS, Kang BS, Bode AM, Dong Z. The intermediate filament protein vimentin is a new target for epigallocatechin gallate. J Biol Chem 2005; 280:16882-90. [PMID: 15713670 DOI: 10.1074/jbc.m414185200] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Epigallocatechin gallate (EGCG) is the major active polyphenol in green tea. Protein interaction with EGCG is a critical step in the effects of EGCG on the regulation of various key proteins involved in signal transduction. We have identified a novel molecular target of EGCG using affinity chromatography, two-dimensional electrophoresis, and mass spectrometry for protein identification. Spots of interest were identified as the intermediate filament, vimentin. The identification was confirmed by Western blot analysis using an anti-vimentin antibody. Experiments using a pull-down assay with [3H]EGCG demonstrate binding of EGCG to vimentin with a Kd of 3.3 nm. EGCG inhibited phosphorylation of vimentin at serines 50 and 55 and phosphorylation of vimentin by cyclin-dependent kinase 2 and cAMP-dependent protein kinase. EGCG specifically inhibits cell proliferation by binding to vimentin. Because vimentin is important for maintaining cellular functions and is essential in maintaining the structure and mechanical integration of the cellular space, the inhibitory effect of EGCG on vimentin may further explain its anti-tumor-promoting effect.
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MESH Headings
- Amino Acid Sequence
- Animals
- Anticarcinogenic Agents/pharmacology
- Antineoplastic Agents/pharmacology
- Blotting, Western
- Catechin/analogs & derivatives
- Catechin/chemistry
- Cell Line
- Cell Proliferation
- Chromatography, Affinity
- Cyclic AMP-Dependent Protein Kinases/chemistry
- Dose-Response Relationship, Drug
- Electrophoresis, Gel, Two-Dimensional
- Flavonoids/chemistry
- Genetic Vectors
- Glutathione Transferase/metabolism
- Humans
- Immunoprecipitation
- Inhibitory Concentration 50
- Kinetics
- Mice
- Microscopy, Fluorescence
- Models, Chemical
- Molecular Sequence Data
- Peptides/chemistry
- Phenols/chemistry
- Phosphorylation
- Polyphenols
- Protein Binding
- Protein Structure, Tertiary
- RNA, Small Interfering/metabolism
- Serine/chemistry
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Time Factors
- Vimentin/chemistry
- Vimentin/metabolism
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Affiliation(s)
- Svetlana Ermakova
- Hormel Institute, University of Minnesota, Austin, Minnesota 55912, USA
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9
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Cheng TJ, Tseng YF, Chang WM, Chang MDT, Lai YK. Retaining of the assembly capability of vimentin phosphorylated by mitogen-activated protein kinase-activated protein kinase-2. J Cell Biochem 2003; 89:589-602. [PMID: 12761892 DOI: 10.1002/jcb.10511] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Intermediate filament (IF) networks can be regulated by phosphorylation of unit proteins, such as vimentin, by specific kinases leading to reorganization of the IF filamentous structure. Recently, we identified mitogen-activated protein kinase-activated protein kinase-2 (MAPKAP kinase-2) as a vimentin kinase (Cheng and Lai [1998] J. Cell. Biochem. 71:169-181). Herein we describe the results of further in vitro studies investigating the effects of MAPKAP kinase-2 phosphorylation on vimentin and the effects of the phosphorylation on the filamentous structure. We show that MAPKAP kinase-2 mainly phosphorylates vimentin at Ser-38, Ser-50, Ser-55, and Ser-82, residues all located in the head domain of the protein. Surprisingly, and in stark contrast to phosphorylation by most other kinases, phosphorylation of vimentin by MAPKAP kinase-2 has no discernable effect on its assembly. It suggested that structure disassembly is not the only obligated consequence of phosphorylated vimentin as regulated by other kinases. Finally, a mutational analysis of each of the phosphorylated serine residues in vimentin suggested that no single serine site was primarily responsible for structure maintenance, implying that the retention of filamentous structure may be the result of the coordinated action of several phosphorylated serine sites. This also shed new lights on the functional task(s) of vimentin that is intermediate filament proteins might provide a phosphate reservoir to accommodate the phosphate surge without any structural changes.
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Affiliation(s)
- Ting-Jen Cheng
- Department of Life Science, National Tsing Hua University, Hsinshu, Taiwan 30013, Republic of China
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10
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Pirpignani ML, Rivera E, Hellman U, Biscoglio de Jiménez Bonino M. Structural and immunological aspects of Polybia scutellaris Antigen 5. Arch Biochem Biophys 2002; 407:224-30. [PMID: 12413495 DOI: 10.1016/s0003-9861(02)00554-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vespid venoms contain Antigen 5, an important allergen whose primary structure and immunological behavior have been extensively studied from venoms of vespids of the Northern Hemisphere. We report herein structural and immunological aspects of Antigen 5 from Polybia scutellaris subspecies rioplatensis (vulgar name: camoati) found in South America. Mast cell degranulation, histamine release, and IgE induction experiments performed in mice allow us to suggest that P. scutellaris Antigen 5 is a variant with reduced IgE response and anaphylactic activity. Sequence data indicate that the protein has a 72.5-90.3% similarity to that of members of the vespid Antigen 5 family with an already known primary structure. Moreover, results suggest that the protein-a new member of an extracellular protein superfamily-could be a good candidate for immunotherapy related to vespid allergy.
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Affiliation(s)
- María L Pirpignani
- Instituto de Química y Fisicoquímica Biológicas (UBA-CONICET), Junin 956, Universidad de Buenos Aires, Buenos Aires, Argentina
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11
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Tözsér J, Bagossi P, Boross P, Louis JM, Majerova E, Oroszlan S, Copeland TD. Effect of serine and tyrosine phosphorylation on retroviral proteinase substrates. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 265:423-9. [PMID: 10491200 DOI: 10.1046/j.1432-1327.1999.00756.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vimentin, a cellular substrate of HIV type 1 (HIV-1) proteinase, contains a protein kinase C (PKC) phosphorylation site at one of its cleavage sites. Peptides representing this site were synthesized in P2 Ser-phosphorylated and nonphosphorylated forms. While the nonphosphorylated peptide was a fairly good substrate of the enzyme, phosphorylation prevented hydrolysis. Phosphorylation of human recombinant vimentin by PKC prevented its processing within the head domain, where the phosphorylation occurred. Oligopeptides representing naturally occurring cleavage sites at the C-terminus of the Rous sarcoma virus integrase were assayed as substrates of the avian proteinase. Unlike the nonphosphorylated peptides, a Ser-phosphorylated peptide was not hydrolyzed by the enzyme at the Ser-Pro bond, suggesting the role of previously established phosphorylation in processing at this site. Ser-phosphorylated and Tyr-phosphorylated forms of model substrates were also tested as substrates of the HIV-1 and the avian retroviral proteinases. In contrast to the moderate effect of P4 Ser phosphorylation, phosphorylation of P1 Tyr prevented substrate hydrolysis by HIV-1 proteinase. Substrate phosphorylation had substantially smaller effects on the hydrolysis by the avian retroviral proteinase. As the active retroviral proteinase as well as various protein kinases are incorporated into mature virions, substrate phosphorylation resulting in attenuation or prevention of proteolytic processing may have important consequences in the regulation of the retroviral life cycle as well as in virus-host cell interactions.
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Affiliation(s)
- J Tözsér
- Department of Biochemistry and Molecular Biology, University Medical School of Debrecen, Hungary.
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12
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Gabel S, Benefield J, Meisinger J, Petruzzelli GJ, Young MR. Protein phosphatases 1 and 2A maintain endothelial cells in a resting state, limiting the motility that is needed for the morphogenic process of angiogenesis. Otolaryngol Head Neck Surg 1999; 121:463-8. [PMID: 10504605 DOI: 10.1016/s0194-5998(99)70238-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Angiogenesis that is induced by cancers, including those of the head and neck, requires endothelial cells to shift from a nonmotile resting state to an increased level of motility. Using a human microvascular endothelial cell line, this study shows the importance of the serine/threonine protein phosphatases 1 (PP1) and 2A (PP2A) in restricting endothelial cell motility. Treatment of endothelial cells with increasing concentrations of the PP1 and PP2A inhibitor okadaic acid resulted in cell rounding and increased motility, which was accompanied by cytoskeletal disorganization involving a loss of filamentous beta-tubulin and F-actin. These effects occurred at okadaic acid levels that selectively inhibit PP2A and became more prominent with higher levels that inhibit both PP2A and PP1. This study shows the importance of PP1 and PP2A in maintaining cytoskeletal organization, thereby limiting endothelial cell motility, and suggests that pharmacologic approaches to enhance PP1 and PP2A activities may be useful in preventing key events of the angiogenic process.
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Affiliation(s)
- S Gabel
- Department of Otolaryngology-Head and Neck Surgery, Loyola University Medical Center, Maywood, USA
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13
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Chan WH, Yu JS, Yang SD. PAK2 is cleaved and activated during hyperosmotic shock-induced apoptosis via a caspase-dependent mechanism: evidence for the involvement of oxidative stress. J Cell Physiol 1999; 178:397-408. [PMID: 9989786 DOI: 10.1002/(sici)1097-4652(199903)178:3<397::aid-jcp14>3.0.co;2-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hyperosmotic shock elicits a stress response in mammalian cells and can lead to apoptotic cell death. In the present study, we report that hyperosmotic shock can induce activation of a 36 kDa kinase detected by an in-gel kinase assay in several cell types, including mouse Balb/c 3T3 fibroblasts, and human Hep 3B and A431 cells. This 36 kDa kinase can be recognized by an antibody against the C-terminal region of a family of p21Cdc42/Rac-activated kinases (PAKs) on immunoblot. Further studies with this antibody and a PAK2-specific antibody against the N-terminal region of PAK2 demonstrate that hyperosmotic shock can induce cleavage of PAK2 to generate a 36 kDa C-terminal catalytic fragment in cells. The cleavage and activation of PAK2 was found to be closely associated with both DNA fragmentation and activation of an ICE/CED-3 family cysteine protease termed caspase-3 in hyperosmotically shocked cells. Furthermore, pretreating the cells with two caspase inhibitors (Ac-DEVD-cho and Ac-YVAD-cmk) could inhibit both cleavage/activation of PAK2 and DNA fragmentation induced by hyperosmotic shock. Moreover, all these hyperosmotic shock-induced changes (i.e., activation of caspase-3, cleavage/activation of PAK2, and DNA fragmentation) in cells could be blocked by antioxidants such as ascorbic acid (vitamine C), alpha-tocopherol (vitamine E), dithiothreitol, beta-mercaptoethanol, and glutathione. Taken together, our results show that PAK2 is cleaved and activated via a caspase-dependent mechanism during hyperosmotic shock-induced apoptosis and suggest the involvement of antioxidant-preventable oxidative stress in inducing this process.
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Affiliation(s)
- W H Chan
- Department of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
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14
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Cheng TJ, Lai YK. Identification of mitogen-activated protein kinase-activated protein kinase-2 as a vimentin kinase activated by okadaic acid in 9L rat brain tumor cells. J Cell Biochem 1998. [DOI: 10.1002/(sici)1097-4644(19981101)71:2<169::aid-jcb3>3.0.co;2-t] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Prasad SC, Thraves PJ, Kuettel MR, Srinivasarao GY, Dritschilo A, Soldatenkov VA. Apoptosis-associated proteolysis of vimentin in human prostate epithelial tumor cells. Biochem Biophys Res Commun 1998; 249:332-8. [PMID: 9712696 DOI: 10.1006/bbrc.1998.9137] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Vimentin intermediate filaments (IF) are responsible for regulation of cell attachment and subcellular organization. Using an in vitro model system of human prostate epithelial cells (267B1-XR), we demonstrate that a series of vimentin proteolytic fragments represent some of the differentially expressed proteins in 2D-gel profiles of the apoptotic cells undergoing ionizing radiation-induced cell death. A caspase-sensitive motif search suggests that the type III IF protein (vimentin) is subject to proteolysis to promote the execution phase of apoptosis, in a manner similar to the well-established type V (lamins) and type I (keratins 18, 19) IF proteins. Furthermore, vimentin and a few of its derived polypeptides, reported to be specific to the apoptotic process, correspond to ubiquinated proteins, thus pointing to the complex interrelationships of protein ubiquination in solubilizing the IF network during apoptosis.
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Affiliation(s)
- S C Prasad
- Department of Radiation Medicine, Division of Radiation Research, Vincent T. Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA.
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Yu JS, Chen WJ, Ni MH, Chan WH, Yang SD. Identification of the regulatory autophosphorylation site of autophosphorylation-dependent protein kinase (auto-kinase). Evidence that auto-kinase belongs to a member of the p21-activated kinase family. Biochem J 1998; 334 ( Pt 1):121-31. [PMID: 9693111 PMCID: PMC1219670 DOI: 10.1042/bj3340121] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Autophosphorylation-dependent protein kinase (auto-kinase) was identified from pig brain and liver on the basis of its unique autophosphorylation/activation property [Yang, Fong, Yu and Liu (1987) J. Biol. Chem. 262, 7034-7040; Yang, Chang and Soderling (1987) J. Biol. Chem. 262, 9421-9427]. Its substrate consensus sequence motif was determined as being -R-X-(X)-S*/T*-X3-S/T-. To characterize auto-kinase further, we partly sequenced the kinase purified from pig liver. The N-terminal sequence (VDGGAKTSDKQKKKAXMTDE) and two internal peptide sequences (EKLRTIV and LQNPEK/ILTP/FI) of auto-kinase were obtained. These sequences identify auto-kinase as a C-terminal catalytic fragment of p21-activated protein kinase 2 (PAK2 or gamma-PAK) lacking its N-terminal regulatory region. Auto-kinase can be recognized by an antibody raised against the C-terminal peptide of human PAK2 by immunoblotting. Furthermore the autophosphorylation site sequence of auto-kinase was successfully predicted on the basis of its substrate consensus sequence motif and the known PAK2 sequence, and was further demonstrated to be RST(P)MVGTPYWMAPEVVTR by phosphoamino acid analysis, manual Edman degradation and phosphopeptide mapping via the help of phosphorylation site analysis of a synthetic peptide corresponding to the sequence of PAK2 from residues 396 to 418. During the activation process, auto-kinase autophosphorylates mainly on a single threonine residue Thr402 (according to the sequence numbering of human PAK2). In addition, a phospho-specific antibody against a synthetic phosphopeptide containing this identified sequence was generated and shown to be able to differentially recognize the activated auto-kinase autophosphorylated at Thr402 but not the non-phosphorylated/inactive auto-kinase. Immunoblot analysis with this phospho-specific antibody further revealed that the change in phosphorylation level of Thr402 of auto-kinase was well correlated with the activity change of the kinase during both autophosphorylation/activation and protein phosphatase-mediated dephosphorylation/inactivation processes. Taken together, our results identify Thr402 as the regulatory autophosphorylation site of auto-kinase, which is a C-terminal catalytic fragment of PAK2.
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Affiliation(s)
- J S Yu
- Department of Cell and Molecular Biology, Institute of Basic Medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China.
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Chu JJ, Chen KD, Lin YL, Fei CY, Chiang AS, Chiang CD, Lai YK. Taxol induces concomitant hyperphosphorylation and reorganization of vimentin intermediate filaments in 9l rat brain tumor cells. J Cell Biochem 1998. [DOI: 10.1002/(sici)1097-4644(19980315)68:4<472::aid-jcb7>3.0.co;2-n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Young MR, Lozano Y. Inhibition of tumor invasiveness by 1alpha,25-dihydroxyvitamin D3 coupled to a decline in protein kinase A activity and an increase in cytoskeletal organization. Clin Exp Metastasis 1997; 15:102-10. [PMID: 9062386 DOI: 10.1023/a:1018492525027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The capacity of cloned metastatic Lewis lung carcinoma cells (LLC-LN7) to invade through reconstituted basement membrane-coated filters was reduced after incubation with 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3]. This was observed at doses as low as 10(-10) M 1,25(OH)2D3. The 1,25(OH)2D3-treated cells also had reduced levels of protein kinase A (PKA) activity and an increase in the level of polymerized actin, properties that have previously been demonstrated for less metastatic LLC variants. In addition, levels of the intermediate filament protein vimentin increased in 1,25(OH)2D3-treated LLC-LN7 tumor cells. In contrast, the levels and distribution of tubulin were not affected by 1,25(OH)2D3. The possibility that the decline in PKA activity was involved in the 1,25(OH)2D3 modulation of the cytoskeletal components was evaluated. To accomplish this, LLC-7 transfectants whose PKA levels were blocked due to expression of a mutated PKA R(1alpha) subunit (LN7-REV) were incubated with 1,25(OH)2D3 and their levels of F-actin were measured. In the absence of 1,25(OH)2D3 treatment, the PKA-defective LN7-REV cells had an increased level of polymerized actin as compared to the wild-type LLC-LN7 cells. This level of F-actin was minimally affected by 1,25(OH)2D3, suggesting that PKA activity is required for 1,25(OH)2D3 modulation of actin polymerization. These studies show that 1,25(OH)2D3 can reduce PKA activity in tumor cells, and that this reduction in PKA may be an intermediate signal through which 1,25(OH)2D3 affects the cytoskeleton and diminishes tumor invasiveness.
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Affiliation(s)
- M R Young
- Department of Research Services, Hines V.A. Hospital, IL 60141, USA.
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Meisinger J, Patel S, Vellody K, Bergstrom R, Benefield J, Lozano Y, Young MR. Protein phosphatase-2A association with microtubules and its role in restricting the invasiveness of human head and neck squamous cell carcinoma cells. Cancer Lett 1997; 111:87-95. [PMID: 9022132 DOI: 10.1016/s0304-3835(96)04517-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The role of protein phosphatase-2A (PP-2A) in regulating the motility and adhesion of human head and neck squamous cell carcinomas (HNSCC) was investigated. Immunofluorescent staining of these HNSCC cells showed PP-2A can co-localize with microtubules. That the PP-2A influences motility was shown by the increase in HNSCC cell migration through laminin and vitronectin when PP-2A was selectively inhibited with low dose okadaic acid, and by the reduction in invasion through these same matrix components by elevators of PP-2A activity. Motility of HNSCC cells through collagen I or fibronectin was not modulated by PP-2A. The reduction in HNSCC migration through vitronectin or laminin that resulted from treatment with PP-2A elevators was associated with an increase in cellular adhesiveness to these same ECM components. These studies show the association of PP-2A with the cellular cytoskeleton and its role in restricting the invasiveness of tumor cells through select extracellular matrix components.
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Affiliation(s)
- J Meisinger
- Department of Research Services, Hines V.A. Hospital, IL 60141, USA
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