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Schopfer LM, Onder S, Lockridge O. Evaluation of mass spectrometry MS/MS spectra for the presence of isopeptide crosslinked peptides. PLoS One 2021; 16:e0254450. [PMID: 34242352 PMCID: PMC8270460 DOI: 10.1371/journal.pone.0254450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/25/2021] [Indexed: 12/14/2022] Open
Abstract
Isopeptide crosslinked proteins can be the product of transglutaminase or of exposure to organophosphorus toxicants (OP). Transglutaminase links glutamine to lysine with loss of ammonia. OP toxicants induce a link between glutamic acid and lysine with loss of water. Our goal was to establish criteria to distinguish real from false isopeptide crosslinks reported by software searches of mass spectrometry data. We used fragmentation spectra of tryptic peptides from MAP-rich tubulin Sus scrofa as a test system for detection of naturally-occurring isopeptide crosslinks. Data were analyzed with Protein Prospector. Criteria for the assignments included the presence of at least 1 crosslink specific product ion, fragment ions from both peptides, Protein Prospector scores ≥20, and best fit of the MS/MS data to the crosslinked peptide as opposed to a linear peptide. Out of 301,364 spectra, 15 potential transglutaminase-type crosslinked peptide candidates were identified. Manual evaluation of these MS/MS spectra reduced the number to 1 valid crosslink between Q112 of NFH and K368 of Tau. Immunopurification with anti-isopeptide 81D1C2 confirmed that MAP-rich tubulin contained only one isopeptide. Support for this isopeptide bond was obtained by showing that transglutaminase was capable of incorporating dansyl-aminohexyl -QQIV into K368. A model of the KIETHK-QLEAHNR isopeptide was synthesized with the aid of transglutaminase. MS/MS spectra of the model validated our interpretation of the native isopeptide. An OP-induced isopeptide bond between K163 of tubulin alpha-1A and E158 of tubulin beta-4B was induced by treating MAP-rich tubulin with 100 μM chlorpyrifos oxon. This crosslink was supported by the criteria described above and by the presence of diethoxyphospho-lysine 163 in the tubulin alpha-1A peptide. The information obtained in this work is valuable for future studies that aim to understand why exposure to OP is associated with increased risk of neurodegenerative disease.
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Affiliation(s)
- Lawrence M. Schopfer
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Seda Onder
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
- Department of Biochemistry, School of Pharmacy, Hacettepe University, Ankara, Turkey
| | - Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
- * E-mail:
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Cheng M, Liu Z, Ji W, Zheng J, Zeng H, Guo F, He P. Tissue Transglutaminase Impairs HTR-8/SVneo Trophoblast Cell Invasion via the PI3K/AKT Signaling Pathway. Gynecol Obstet Invest 2021; 86:264-272. [PMID: 34139701 DOI: 10.1159/000515086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/06/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The pathogenesis of preeclampsia (PE) is associated with impaired trophoblast invasion, which results in placental insufficiency. Our earlier studies demonstrated that tissue transglutaminase (tTG) is highly expressed in human PE serum. However, whether tTG participates in trophoblast invasion remains unclear. The aim of the present study was to determine the role and mechanism of tTG in regulating matrix metalloproteinase (MMP)-2/MMP-9 expression to reduce trophoblast invasiveness in PE. METHODS HTR-8/SVneo cells were transfected with a lentivirus vector and small interfering RNA targeting tTG. The protein level was detected by Western blotting. Cell proliferation and apoptosis were assessed by MTS and flow cytometry assays, respectively. Cell invasion was investigated by Transwell assay. In addition, the influence of tTG on PI3K and AKT mRNA levels in HTR-8/SVneo cells was evaluated using reverse transcription-quantitative PCR. RESULTS tTG-overexpression inhibited HTR-8/SVneo cell proliferation and invasion and promoted apoptosis. In addition, upregulation of tTG induced an increase of PI3K and phosphorylated AKT and a decrease of MMP-2 and MMP-9 expression. tTG-knockdown significantly promoted the proliferation and invasion of HTR-8/SVneo cells and inhibited the apoptosis. Furthermore, the PI3K expression level was reduced, and the MMP-2/MMP-9 protein levels were increased. CONCLUSION Taken together, the present study demonstrated that tTG-overexpression inhibited HTR-8/SVneo cell invasion via reducing the expression of MMP-2 and MMP-9 by activating PI3K/AKT signaling pathway, which may lead to the occurrence or development of PE. The present data provide new insights into modulation of tTG expression as a potential therapeutic target for PE.
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Affiliation(s)
- Mi Cheng
- Department of Obstetrics, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Zequn Liu
- Department of Prenatal Diagnostic Center, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Wanqing Ji
- Department of Obstetrics, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Jie Zheng
- Department of Obstetrics, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Huiqian Zeng
- Department of Obstetrics, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Fang Guo
- Department of Obstetrics, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
| | - Ping He
- Department of Obstetrics, Guangzhou Medical University Affiliated Guangzhou Women and Children's Medical Center, Guangzhou, China
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Characteristic fragment ions associated with dansyl cadaverine and biotin cadaverine adducts on glutamine. Anal Biochem 2020; 600:113718. [PMID: 32335065 DOI: 10.1016/j.ab.2020.113718] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/18/2020] [Accepted: 04/03/2020] [Indexed: 12/16/2022]
Abstract
Glutamine residues susceptible to transglutaminase-catalyzed crosslinking can be identified by incorporation of dansyl cadaverine or biotin cadaverine. Bacterial transglutaminase and human transglutaminase 2 were used to modify residues in beta-casein with dansyl cadaverine. Bacterial transglutaminase was used to modify residues in human butyrylcholinesterase with biotin cadaverine. Tryptic peptides were analyzed by LC-MS/MS on an Orbitrap Fusion Lumos mass spectrometer. Modified residues were identified in Protein Prospector searches of mass spectrometry data. The MS/MS spectra from modified casein included intense peaks at 336.2, 402.2, and 447.2 for fragments of dansyl cadaverine adducts on glutamine. The MS/MS spectra from modified butyrylcholinesterase included intense peaks at 329.2, 395.2, and 440.2 for fragments of biotin cadaverine adducts on glutamine. No evidence for transglutaminase-catalyzed adducts on glutamic acid, aspartic acid, or asparagine was found. Consistent with expectation, it was concluded that bacterial transglutaminase and human transglutaminase 2 specifically modify glutamine. The characteristic ions associated with dansyl cadaverine and biotin cadaverine adducts on glutamine are useful markers for modified peptides.
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4
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Affiliation(s)
- Laszlo Lorand
- Department of Cell and Molecular BiologyNorthwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Siiri E. Iismaa
- Molecular Cardiology and Biophysics DivisionVictor Chang Cardiac Research Institute Darlinghurst New South Wales Australia
- St Vincent's Clinical SchoolUniversity of New South Wales Kensington New South Wales Australia
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5
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Wang Q, Wang D, Yan G, Qiao Y, Sun L, Zhu B, Wang X, Tang C. SERCA2a was serotonylated and may regulate sino-atrial node pacemaker activity. Biochem Biophys Res Commun 2016; 480:492-497. [DOI: 10.1016/j.bbrc.2016.10.082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 10/22/2016] [Indexed: 10/20/2022]
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Ahmad E, Fatima MT, Hoque M, Owais M, Saleemuddin M. Fibrin matrices: The versatile therapeutic delivery systems. Int J Biol Macromol 2015; 81:121-36. [PMID: 26231328 DOI: 10.1016/j.ijbiomac.2015.07.054] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 07/24/2015] [Accepted: 07/26/2015] [Indexed: 12/12/2022]
Abstract
Fibrin sealants, that have been employed for over a century by surgeons to stop post surgery bleeding, are finding novel applications in the controlled delivery of antibiotics and several other therapeutics. Fibrinogen can be easily purified from blood plasma and converted by thrombolysis to fibrin that undergoes spontaneous aggregation to form insoluble clot. During the gelling, fibrin can be formulated into films, clots, threads, microbeads, nanoconstructs and nanoparticles. Whole plasma clots in the form of beads and microparticles can also be prepared by activating endogenous thrombin, for possible drug delivery. Fibrin formulations offer remarkable scope for controlling the porosity as well as in vivo degradability and hence the release of the associated therapeutics. Binding/covalent-linking of therapeutics to the fibrin matrix, crosslinking of the matrix with bifunctional reagents and coentrapment of protease inhibitors have been successful in regulating both in vitro and in vivo release of the therapeutics. The release rates can also be remarkably lowered by preentrapment of therapeutics in insoluble particles like liposomes or by anchoring them to the matrix via molecules that bind them as well as fibrin.
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Affiliation(s)
- Ejaj Ahmad
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | | | - Mehboob Hoque
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Mohammad Owais
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Mohammed Saleemuddin
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
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7
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Effect of salmon plasma protein on Pacific whiting surimi gelation under various ohmic heating conditions. Lebensm Wiss Technol 2015. [DOI: 10.1016/j.lwt.2014.12.049] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Transglutaminase 2 is essential for adherence of Porphyromonas gingivalis to host cells. Proc Natl Acad Sci U S A 2014; 111:5355-60. [PMID: 24706840 DOI: 10.1073/pnas.1402740111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Porphyromonas gingivalis is the major causative agent of periodontitis, and it may also be involved in the development of systemic diseases (atherosclerosis, rheumatoid arthritis). P. gingivalis is found on and within oral and gingival epithelial cells following binding to surface components of host cells, which serve as receptors for the bacterium. Evidence is presented in this study that shows that transglutaminase 2 (TG2) plays a critical role in the adherence of P. gingivalis to host cells. Studies of confocal microscopy indicate colocalization of P. gingivalis with TG2 on the surface of HEp-2 epithelial cells, with clusters of TG2 seen at bacterial attachment sites. By silencing the expression of TG2 with siRNA in HEp-2 cells, P. gingivalis association was greatly diminished. The bacterium does not bind well to a mouse fibroblast cell line that produces low amounts of surface TG2, but binding can be restored by introduction of TG2 expressed on a plasmid. TG2 can form very tight complexes with fibronectin (FN), and the complementary binding sites of the two proteins are known. A synthetic peptide that mimics the main FN-binding sequence of TG2 blocks the formation of TG2-FN complexes and is highly effective in inhibiting adherence of P. gingivalis to host cells. These findings provide evidence of a role for cell-surface TG2 in bacterial attachment and subsequent internalization.
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Detyrosinated Glu-tubulin is a substrate for cellular Factor XIIIA transglutaminase in differentiating osteoblasts. Amino Acids 2014; 46:1513-26. [DOI: 10.1007/s00726-014-1719-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 02/26/2014] [Indexed: 11/26/2022]
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10
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Fatima MT, Ahmad E, Saleemuddin M. Entrapment in plasma microparticles: A promising strategy for antigen delivery. J Biomed Mater Res B Appl Biomater 2014; 102:1244-54. [DOI: 10.1002/jbm.b.33108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/21/2013] [Accepted: 01/04/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Munazza T. Fatima
- The Interdisciplinary Biotechnology Unit; Aligarh Muslim University; Aligarh 202002 India
| | - Ejaj Ahmad
- The Interdisciplinary Biotechnology Unit; Aligarh Muslim University; Aligarh 202002 India
| | - Mohammed Saleemuddin
- The Interdisciplinary Biotechnology Unit; Aligarh Muslim University; Aligarh 202002 India
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Bergamini CM, Collighan RJ, Wang Z, Griffin M. Structure and regulation of type 2 transglutaminase in relation to its physiological functions and pathological roles. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2011; 78:1-46. [PMID: 22220471 DOI: 10.1002/9781118105771.ch1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Carlo M Bergamini
- Deparment of Biochemistry and Molecular Biology, University of Ferrara, Italy
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12
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Hoffmann BR, Annis DS, Mosher DF. Reactivity of the N-terminal region of fibronectin protein to transglutaminase 2 and factor XIIIA. J Biol Chem 2011; 286:32220-30. [PMID: 21757696 DOI: 10.1074/jbc.m111.255562] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Transglutaminase 2 (TG2) is secreted by a non-classical pathway into the extracellular space, where it has several activities pertinent to fibronectin (FN), including binding to the gelatin-binding domain of FN and acting as an integrin co-receptor. Glutamines in the N-terminal tail of FN are known to be susceptible to transamidation by both TG2 and activated blood coagulation factor XIII (FXIIIa). We used immunoblotting, limited proteolysis, and mass spectrometry to localize glutamines within FN that are subject to TG2-catalyzed incorporation of dansylcadaverine in comparison to residues modified by FXIIIa. Such analysis of plasma FN indicated that Gln-3, Gln-7, and Gln-9 in the N-terminal tail and Gln-246 of the linker between fifth and sixth type I modules ((5)F1 and (6)F1) are transamidated by both enzymes. Only minor incorporation of dansylcadaverine was detected elsewhere. Labeling of C-terminally truncated FN constructs revealed efficient TG2- or FXIIIa-catalyzed dansylcadaverine incorporation into the N-terminal residues of constructs as small as the 29-kDa fragment that includes (1-5)F1 and lacks modules from the adjacent gelatin-binding domain. However, when only (1-3)F1 were present, dansylcadaverine incorporation into the N-terminal residues of FN was lost and instead was in the enzymes, near the active site of TG2 and terminal domains of FXIIIa. Thus, these results demonstrate that FXIIIa and TG2 act similarly on glutamines at either end of (1-5)F1 and transamidation specificity of both enzymes is achieved through interactions with the intact 29K fragment.
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Affiliation(s)
- Brian R Hoffmann
- Department of Biomolecular Chemistry and Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Abstract
Aim: The aim of the study was to prepare a drug-entrapped, beaded form of blood plasma for possible sustained drug delivery. Method: Blood plasma mixed with various drugs was enriched with CaCl2 and transferred in the form of small droplets on to a glass slide covered with parafilm. Clot formation was induced by incubation at 37°C. Results: Plasma-bead entrapped tetracycline, amphotericin B and daunorubicin were released gradually in vitro. Crosslinking of the beads with glutaraldehyde decreased the release rate of drugs remarkably. The plasma bead-entrapped cefotaxime administered subcutaneously in mice was released in a slow and sustained fashion and remained in circulation for a longer duration than the antibiotic administered in the free form. Conclusion: The plasma beads have potential for the sustained delivery of drugs in vivo, since their preparation does not require additional thrombin or other proteins and can be readily accomplished by using autologous plasma, thereby minimizing the risk of immunological complications.
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Dihydroisoxazole analogs for labeling and visualization of catalytically active transglutaminase 2. ACTA ACUST UNITED AC 2011; 18:58-66. [PMID: 21276939 DOI: 10.1016/j.chembiol.2010.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 11/02/2010] [Accepted: 11/02/2010] [Indexed: 01/31/2023]
Abstract
We report the synthesis and preliminary characterization of "clickable" inhibitors of human transglutaminase 2 (TG2). These inhibitors possess the 3-halo-4,5-dihydroisoxazole warhead along with bioorthogonal groups such as azide or alkyne moieties that enable subsequent covalent modification with fluorophores. Their mechanism for inhibition of TG2 is based on halide displacement, resulting in the formation of a stable imino thioether. Inhibition assays against recombinant human TG2 revealed that some of the clickable inhibitors prepared in this study have comparable specificity as benchmark dihydroisoxazole inhibitors reported earlier. At low micromolar concentrations they completely inhibited transiently activated TG2 in a WI-38 fibroblast scratch assay and could subsequently be used to visualize the active enzyme in situ. The potential use of these inhibitors to probe the role of TG2 in celiac sprue as well as other diseases is discussed.
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Kristiansen GK, Andersen MD. Reversible activation of cellular factor XIII by calcium. J Biol Chem 2011; 286:9833-9. [PMID: 21245142 DOI: 10.1074/jbc.m110.174128] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Factor XIII (FXIII) is a pro-transglutaminase found in the plasma as well as intracellularly in platelets and macrophages. Plasma FXIII is activated by thrombin cleavage (FXIIIa*) and acts in the final stages of blood coagulation cascade. In contrast, the function and activation of cellular FXIII are less characterized. Cellular FXIII relies on a conformational activation of the protein. The nonproteolytic activation of FXIII to FXIIIa° induced by Ca(2+) alone is well known, but up until now it has been discussed under which conditions the process can be induced and whether it can be reversed. Here, we study the nature of the Ca(2+)-induced FXIII activation. Previously used methods to evaluate FXIII activity detect both FXIIIa* and FXIIIa° because they rely on occurrence of enzyme activity or on active site Cys-314 solvent accessibility. Therefore, an analytical HPLC method was developed that separates zymogen recombinant FXIII (rFXIII) from rFXIIIa°. The data demonstrate that nonproteolytic activation and deactivation are highly dependent on Ca(2+) concentration, buffer, and salt components. Moreover, it is established that Ca(2+) activation of rFXIII is fully reversible, and only 2-5 mm CaCl(2) is sufficient to retain full rFXIIIa° activity. However, below 2 mm CaCl(2) the rFXIIIa° molecule deactivates. The deactivated molecule can subsequently undergo a new activation round. Furthermore, it is demonstrated that thermal stress of freeze-dried rFXIII can induce a new predisposed form that activates faster than nonstressed rFXIII.
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Liu Y, Wei L, Laskin DL, Fanburg BL. Role of protein transamidation in serotonin-induced proliferation and migration of pulmonary artery smooth muscle cells. Am J Respir Cell Mol Biol 2010; 44:548-55. [PMID: 20558776 DOI: 10.1165/rcmb.2010-0078oc] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Pulmonary hypertension is characterized by elevated pulmonary artery pressure and pulmonary artery smooth muscle cell (SMC) proliferation and migration. Clinical and experimental evidence suggests that serotonin (5-HT) is important in these responses. We previously demonstrated the participation of the 5-HT transporter and intracellular 5-HT (5-HTi) in the pulmonary vascular SMC-proliferative response to 5-HT. However, the mechanism underlying the intracellular actions of 5-HT is unknown. We speculated that 5-HTi activates SMC growth by post-translational transamidation of proteins via transglutaminase (TGase) activity, a process referred to as serotonylation. To test this hypothesis, serotonylation of pulmonary artery SMC proteins, and their role in 5-HT-induced proliferative and migratory responses, were assessed. 5-HT caused dose- and time-dependent increase in serotonylation of multiple proteins in both bovine and rat pulmonary artery SMCs. Inhibition of TGase with dansylcadaverin blocked this activity, as well as SMC-proliferative and migratory responses to 5-HT. Serotonylation of proteins also was blocked by 5-HT transporter inhibitors, and was enhanced by inhibition of monoamine oxidase, an enzyme known to degrade 5-HTi, indicating that 5-HTi levels regulate serotonylation. Immunoprecipitation assays and HPLC-mass spectral peptide sequencing revealed that a major protein serotonylated by TGase was fibronectin (FN). 5-HT-stimulated SMC serotonylation and proliferation were blocked by FN small interfering (si) RNA. These findings, together with previous observations that FN expression in the lung strongly correlates with the progression of pulmonary hypertension in both experimental animals and humans, suggest an important role of FN serotonylation in the pathogenesis of this disease.
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Affiliation(s)
- Yinglin Liu
- Rutgers University, Piscataway, New Jersey, USA
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Elli L, Bergamini CM, Bardella MT, Schuppan D. Transglutaminases in inflammation and fibrosis of the gastrointestinal tract and the liver. Dig Liver Dis 2009; 41:541-50. [PMID: 19195940 DOI: 10.1016/j.dld.2008.12.095] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 11/28/2008] [Accepted: 12/02/2008] [Indexed: 12/11/2022]
Abstract
Transglutaminases are a family of eight currently known calcium-dependent enzymes that catalyze the cross-linking or deamidation of proteins. They are involved in important biological processes such as wound healing, tissue repair, fibrogenesis, apoptosis, inflammation and cell-cycle control. Therefore, they play important roles in the pathomechanisms of autoimmune, inflammatory and degenerative diseases, many of which affect the gastrointestinal system. Transglutaminase 2 is prominent, since it is central to the pathogenesis of celiac disease, and modulates inflammation and fibrosis in inflammatory bowel and chronic liver diseases. This review highlights our present understanding of transglutaminase function in gastrointestinal and liver diseases and therapeutic strategies that target transglutaminase activities.
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Affiliation(s)
- L Elli
- Center for Prevention and Diagnosis of Celiac Disease, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, via F. Sforza, Milan, Italy.
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Singh P, Shaffer SA, Scherl A, Holman C, Pfuetzner RA, Larson Freeman TJ, Miller SI, Hernandez P, Appel RD, Goodlett DR. Characterization of protein cross-links via mass spectrometry and an open-modification search strategy. Anal Chem 2008; 80:8799-806. [PMID: 18947195 DOI: 10.1021/ac801646f] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Protein-protein interactions are key to function and regulation of many biological pathways. To facilitate characterization of protein-protein interactions using mass spectrometry, a new data acquisition/analysis pipeline was designed. The goal for this pipeline was to provide a generic strategy for identifying cross-linked peptides from single LC/MS/MS data sets, without using specialized cross-linkers or custom-written software. To achieve this, each peptide in the pair of cross-linked peptides was considered to be "post-translationally" modified with an unknown mass at an unknown amino acid. This allowed use of an open-modification search engine, Popitam, to interpret the tandem mass spectra of cross-linked peptides. False positives were reduced and database selectivity increased by acquiring precursors and fragments at high mass accuracy. Additionally, a high-charge-state-driven data acquisition scheme was utilized to enrich data sets for cross-linked peptides. This open-modification search based pipeline was shown to be useful for characterizing both chemical as well as native cross-links in proteins. The pipeline was validated by characterizing the known interactions in the chemically cross-linked CYP2E1-b5 complex. Utility of this method in identifying native cross-links was demonstrated by mapping disulfide bridges in RcsF, an outer membrane lipoprotein involved in Rcs phosphorelay.
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Affiliation(s)
- Pragya Singh
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, USA
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