1
|
Kumar GS. Preparation of Oxidized and Reduced PTP4A1 for Structural and Functional Studies. Methods Mol Biol 2024; 2743:211-222. [PMID: 38147218 DOI: 10.1007/978-1-0716-3569-8_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
The formation of a reversible disulfide bond between the catalytic cysteine and a spatially neighboring cysteine (backdoor) in protein tyrosine phosphatases (PTPs) serves as a critical regulatory mechanism for maintaining the activity of protein tyrosine phosphatases. The failure of such protection results in the formation of irreversibly oxidized cysteines into sulfonic acid in a highly oxidative cellular environment in the presence of free radicals. Hence, it is important to develop methods to interconvert PTPs into reduced and oxidized forms to understand their catalytic function in vitro. Protein tyrosine phosphatase 4A type 1 (PTP4A1), a dual-specificity phosphatase, is catalytically active in the reduced form. Unexpectedly, also its oxidized form performs a key biological function in systemic sclerosis (SSc) by forming a kinase-phosphatase complex with Src kinases. Thus, we developed simple and efficient protocols for producing oxidized and reduced PTP4A1 to elucidate their biological function, which can be extended to study other protein tyrosine phosphatases and other recombinantly produced proteins.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Integrative Structural Biology Laboratory, National Institute of Immunology, New Delhi, India.
| |
Collapse
|
2
|
Hunashal Y, Kumar GS, Choy MS, D'Andréa ÉD, Da Silva Santiago A, Schoenle MV, Desbonnet C, Arthur M, Rice LB, Page R, Peti W. Molecular basis of β-lactam antibiotic resistance of ESKAPE bacterium E. faecium Penicillin Binding Protein PBP5. Nat Commun 2023; 14:4268. [PMID: 37460557 DOI: 10.1038/s41467-023-39966-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
Penicillin-binding proteins (PBPs) are essential for the formation of the bacterial cell wall. They are also the targets of β-lactam antibiotics. In Enterococcus faecium, high levels of resistance to β-lactams are associated with the expression of PBP5, with higher levels of resistance associated with distinct PBP5 variants. To define the molecular mechanism of PBP5-mediated resistance we leveraged biomolecular NMR spectroscopy of PBP5 - due to its size (>70 kDa) a challenging NMR target. Our data show that resistant PBP5 variants show significantly increased dynamics either alone or upon formation of the acyl-enzyme inhibitor complex. Furthermore, these variants also exhibit increased acyl-enzyme hydrolysis. Thus, reducing sidechain bulkiness and expanding surface loops results in increased dynamics that facilitates acyl-enzyme hydrolysis and, via increased β-lactam antibiotic turnover, facilitates β-lactam resistance. Together, these data provide the molecular basis of resistance of clinical E. faecium PBP5 variants, results that are likely applicable to the PBP family.
Collapse
Affiliation(s)
- Yamanappa Hunashal
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Ganesan Senthil Kumar
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
- National Institute of Immunology, New Delhi, India
| | - Meng S Choy
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Éverton D D'Andréa
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | | | - Marta V Schoenle
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Charlene Desbonnet
- Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Michel Arthur
- INSERM, Sorbonne Université, Université Paris Cité, Paris, France
| | - Louis B Rice
- Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA.
| |
Collapse
|
3
|
Zhang R, Kumar GS, Hansen U, Zoccheddu M, Sacchetti C, Holmes ZJ, Lee MC, Beckmann D, Wen Y, Mikulski Z, Yang S, Santelli E, Page R, Boin F, Peti W, Bottini N. Oxidative stress promotes fibrosis in systemic sclerosis through stabilization of a kinase-phosphatase complex. JCI Insight 2022; 7:155761. [PMID: 35451370 PMCID: PMC9089796 DOI: 10.1172/jci.insight.155761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/02/2022] [Indexed: 11/23/2022] Open
Abstract
Systemic sclerosis (SSc) is a fibrotic autoimmune disease characterized by pathogenic activation of fibroblasts enhanced by local oxidative stress. The tyrosine phosphatase PTP4A1 was identified as a critical promoter of TGF-β signaling in SSc. Oxidative stress is known to functionally inactivate tyrosine phosphatases. Here, we assessed whether oxidation of PTP4A1 modulates its profibrotic action and found that PTP4A1 forms a complex with the kinase SRC in scleroderma fibroblasts, but surprisingly, oxidative stress enhanced rather than reduced PTP4A1’s association with SRC and its profibrotic action. Through structural assessment of the oxo-PTP4A1-SRC complex, we unraveled an unexpected mechanism whereby oxidation of a tyrosine phosphatase promotes its function through modification of its protein complex. Considering the importance of oxidative stress in the pathogenesis of SSc and fibrosis, our findings suggest routes for leveraging PTP4A1 oxidation as a potential strategy for developing antifibrotic agents.
Collapse
Affiliation(s)
- Ruiyuan Zhang
- Department of Medicine and.,Department of Biological Sciences, University of California, San Diego, La Jolla, California, USA
| | - Ganesan Senthil Kumar
- Department of Molecular Biology & Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Uwe Hansen
- Institute for Musculoskeletal Medicine, University of Munster, Munster, Germany
| | | | | | | | | | | | | | - Zbigniew Mikulski
- Microscopy and Histology Core Facility, La Jolla Institute for Immunology, La Jolla, California, USA
| | | | | | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Francesco Boin
- Division of Rheumatology, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Wolfgang Peti
- Department of Molecular Biology & Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | | |
Collapse
|
4
|
Kumar GS, Page R, Peti W. 1H, 15N and 13C sequence specific backbone assignment of the MAP kinase binding domain of the dual specificity phosphatase 1 and its interaction with the MAPK p38. Biomol NMR Assign 2021; 15:243-248. [PMID: 34101142 DOI: 10.1007/s12104-021-10012-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
The sequence-specific backbone assignment of the mitogen-activated protein kinase (MAPK) binding domain of the dual-specificity phosphatase 1 (DUSP1) has been accomplished using a uniformly [13C, 15N]-labeled protein. These assignments will facilitate further studies of DUSP1 in the presence of inhibitors/ligands to target MAPK associated diseases and provide further insights into the function of dual-specificity phosphatase 1 in MAPK regulation.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA.
- Integrative Structural Biology Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| |
Collapse
|
5
|
Balachandra SS, Sawant PS, Huilgol PG, Vithya T, Kumar GS, Prasad R. Antimicrobial resistance (AMR) at the community level: An urban and rural case study from Karnataka. J Family Med Prim Care 2021; 10:1404-1411. [PMID: 34041186 PMCID: PMC8140222 DOI: 10.4103/jfmpc.jfmpc_888_20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/14/2020] [Accepted: 10/14/2020] [Indexed: 11/14/2022] Open
Abstract
Context: The emergence of antimicrobial resistance (AMR) is a major public health crisis in India and globally. While national guidelines exist, the sources of data which form the basis of these guidelines are limited to a few well-established tertiary care centres. There is inadequate literature on AMR and antibiotic mismatch from India at community level and even less literature on AMR patterns from rural India. Aims: The aims of this study were as follows: 1) to describe the patterns of AMR at an urban tertiary care hospital and a rural 100 bedded hospital; 2) to compare and contrast the AMR patterns noted with published ICMR guidelines; 3) to examine the issue of AMR and antibiotic mismatch; and 4) to identify local factors influencing drug-bug mismatch at the local level. Settings and Design: The data were obtained from two independently conceived projects (Site 1: Urban tertiary care hospital, Site 2: Rural 100-bedded hospital). Methods and Materials: Local antibiograms were made, and the antibiotic resistance patterns were compared between the urban and rural sites and with data published in the 2017 ICMR national guideline for AMR. Statistical Analysis Used: Descriptive statistics including means and medians were used. Results: Our data reveal: a) a significant mismatch between sensitivity patterns and antibiotics prescribed; b) The national guidelines fail to capture the local picture of AMR, highlighting the need for local data; and c) challenges with data collection/retrieval, access and accuracy of diagnostic tools, administrative issues, and lack of local expertise limit antimicrobial stewardship efforts. Conclusions: Our study finds the burden of AMR high in both rural and urban sites, reinforcing that AMR burden cannot be ignored in rural settings. It also highlights that national data obtained from tertiary care settings fail to capture the local picture, highlighting the need for local data. Mechanisms of linking rural practices, primary health centres, and small hospitals with a common microbiology laboratory and shared data platforms will facilitate antibiotic stewardship at the community level.
Collapse
Affiliation(s)
- Swathi S Balachandra
- Primary Care Physician & Researcher, PCMH Restore Health, Bangalore & Coordinator, Spice Route Movement, Karnataka, Academy of Family Physicians of India (AFPI), Karnataka, India
| | - Prathamesh S Sawant
- Clinical Pharmacist Practitioner, Division of Family Medicine & Primary Care, PCMH Restore Health, Bengaluru, Karnataka, India
| | - Poorva G Huilgol
- Lab Manager, Molecular Solutions Care Health (MSCH), Bengaluru, Karnataka, India
| | - T Vithya
- Department of Clinical Pharmacy Practice, Al Ameen College of Pharmacy, Bengaluru, Karnataka, India
| | - G S Kumar
- Department of Paediatrics, Vivekananda Memorial Hospital (VMH), Swami Vivekananda Youth Movement (SVYM), Saragur, Karnataka, India
| | - Ramakrishna Prasad
- Division of Family Medicine & Primary Care, PCMH Restore Health, AFPI National Centre for Primary Care Research and Policy, Bengaluru, Karnataka, India
| |
Collapse
|
6
|
Kumar GS, Page R, Peti W. The interaction of p38 with its upstream kinase MKK6. Protein Sci 2021; 30:908-913. [PMID: 33554397 DOI: 10.1002/pro.4039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 02/06/2023]
Abstract
Mitogen-activated protein kinase (MAPK; p38, ERK, and JNK) cascades are evolutionarily conserved signaling pathways that regulate the cellular response to a variety of extracellular stimuli, such as growth factors and interleukins. The MAPK p38 is activated by its specific upstream MAPK kinases, MKK6 and MKK3. However, a comprehensive molecular understanding of how these cognate upstream kinases bind and activate p38 is still missing. Here, we combine NMR spectroscopy and isothermal titration calorimetry to define the binding interface between full-length MKK6 and p38. It was shown that p38 engages MKK6 not only via its hydrophobic docking groove, but also influences helix αF, a secondary structural element that plays a key role in organizing the kinase core. It was also shown that, unlike MAPK phosphatases, the p38 conserved docking (CD) site is much less affected by MKK6 binding. Finally, it was demonstrated that these interactions with p38 are conserved independent of the MKK6 activation state. Together, the results revealed differences between specificity markers of p38 regulation by upstream kinases, which do not effectively engage the CD site, and downstream phosphatases, which require the CD site for productive binding.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| |
Collapse
|
7
|
SriChinthu KK, Pavithra V, Kumar GS, Prasad H, Prema P, Yoithapprabhunath TR, Rangarajan N. Evaluation of gingival and periodontal status in obese and non-obese type II diabetic patients - a cross sectional study. Med Pharm Rep 2021; 94:94-98. [PMID: 33629055 PMCID: PMC7880060 DOI: 10.15386/mpr-1686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/14/2020] [Accepted: 05/30/2020] [Indexed: 01/05/2023] Open
Abstract
Objective The aim of this study was to evaluate gingival and periodontal status in obese and non-obese type II Diabetic Patients. Methods The study population comprised of 75 subjects visiting the outpatient department of our institution, divided into three different groups, group 1 (obese diabetic), group 2 (non-obese diabetic), and group 3 (obese, non-diabetic). Diabetic status was assessed with HbA1c values and obesity status was assessed by body mass index (BMI) score greater than or equal to 30 kg/m2. Gingival and periodontal status were assessed using the Gingival Index (GI) and Community Periodontal Index (CPI) respectively. Results The mean gingival index score in group 1, group 2, and group 3 were 1.58, 1.54, and 1.25, respectively. Gingival status was poor among obese and non-obese diabetic subjects (Groups 1 and 2) when compared with obese non-diabetic patients (Group 3). The periodontal status showed that periodontal pockets were increased in diabetic obese group (15.4%), followed by diabetic non obese (4.66%), and non-diabetic obese (2%) group respectively and loss of attachment was severe in diabetic obese group (60.7%), followed by diabetic non obese (45.9%) and non-diabetic obese (15.3%) respectively. Conclusion Gingival and periodontal status was poor in the obese diabetic group compared to non-obese diabetic and obese non diabetic group. Hence, the risk of gingivitis and periodontitis in obese diabetic patients should be addressed earlier to prevent further complications and achieve a good oral health status.
Collapse
Affiliation(s)
- Kenniyan Kumar SriChinthu
- Oral and Maxillofacial Pathology Department, KSR Institute of Dental Science & Research, Tamilnadu, India
| | - Velusamy Pavithra
- Oral and Maxillofacial Pathology Department, KSR Institute of Dental Science & Research, Tamilnadu, India
| | - G S Kumar
- Oral and Maxillofacial Pathology Department, KSR Institute of Dental Science & Research, Tamilnadu, India
| | - Harikrishnan Prasad
- Oral and Maxillofacial Pathology Department, KSR Institute of Dental Science & Research, Tamilnadu, India
| | - Perumal Prema
- Oral and Maxillofacial Pathology Department, KSR Institute of Dental Science & Research, Tamilnadu, India
| | | | - Nagarajan Rangarajan
- Oral and Maxillofacial Pathology Department, Vivekanandha Dental College for Women, Tamilnadu, India
| |
Collapse
|
8
|
Srichinthu KK, Kumar GS, Prasad H, Rajmohan M, Anuthama K, Yoithapprabhunath TR. Expression of epithelial glycoprotein (EGP40) in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC). Indian J Dent Res 2021; 31:738-742. [PMID: 33433512 DOI: 10.4103/ijdr.ijdr_929_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Aim To study the expression of Epithelial Glycoprotein (EGP40) in various grades of Oral Epithelial Dysplasia namely mild, moderate and severe epithelial dysplasia and in various grades of Oral Squamous Cell Carcinoma (OSCC) namely well, moderate & in poorly differentiated squamous cell carcinoma. Material and Methods This laboratory study comprised of 47 samples in which 27 samples were of three different grades of OSCC, Well (n=10), Moderate (n=10) and Poorly differentiated (n=7) and remaining 20 samples were of three different grades of dysplasia [Mild (n=7), Moderate (n=8), Severe dysplasia (n=5)]. All the 47 cases were subjected to immunohistochemical staining to evaluate the expression of EGP40. Chi square was used to analyze the significance of differences in different grades of oral epithelial dysplasia & in different grades of OSCC. Results The percentage of EGP40 immuno positivity was increased from mild to severe dysplasia and the percentage of EGP40 immuno positivity was increased from well to poorly differentiated carcinoma No statistical significance was observed in the immunoreactivity and in the intensity of expression between various grades of oral epithelial dysplasia and oral squamous cell carcinoma. Conclusion The epithelial cell adhesion molecule can be considered as an early marker for predicting malignant transformation of dysplastic epithelial lesions and used as a marker in predicting the OSCC prognosis.
Collapse
Affiliation(s)
- Kenniyan Kumar Srichinthu
- Department of Oral and Maxillofacial Pathology, KSR Institute of Dental Science and Research, Thiruchengodu, Tamil Nadu, India
| | - G S Kumar
- Department of Oral and Maxillofacial Pathology, KSR Institute of Dental Science and Research, Thiruchengodu, Tamil Nadu, India
| | - Harikrishnan Prasad
- Department of Oral and Maxillofacial Pathology, KSR Institute of Dental Science and Research, Thiruchengodu, Tamil Nadu, India
| | - Muthusamy Rajmohan
- Department of Oral and Maxillofacial Pathology, KSR Institute of Dental Science and Research, Thiruchengodu, Tamil Nadu, India
| | | | | |
Collapse
|
9
|
Kirsch K, Zeke A, Tőke O, Sok P, Sethi A, Sebő A, Kumar GS, Egri P, Póti ÁL, Gooley P, Peti W, Bento I, Alexa A, Reményi A. Co-regulation of the transcription controlling ATF2 phosphoswitch by JNK and p38. Nat Commun 2020; 11:5769. [PMID: 33188182 PMCID: PMC7666158 DOI: 10.1038/s41467-020-19582-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/21/2020] [Indexed: 01/26/2023] Open
Abstract
Transcription factor phosphorylation at specific sites often activates gene expression, but how environmental cues quantitatively control transcription is not well-understood. Activating protein 1 transcription factors are phosphorylated by mitogen-activated protein kinases (MAPK) in their transactivation domains (TAD) at so-called phosphoswitches, which are a hallmark in response to growth factors, cytokines or stress. We show that the ATF2 TAD is controlled by functionally distinct signaling pathways (JNK and p38) through structurally different MAPK binding sites. Moreover, JNK mediated phosphorylation at an evolutionarily more recent site diminishes p38 binding and made the phosphoswitch differently sensitive to JNK and p38 in vertebrates. Structures of MAPK-TAD complexes and mechanistic modeling of ATF2 TAD phosphorylation in cells suggest that kinase binding motifs and phosphorylation sites line up to maximize MAPK based co-regulation. This study shows how the activity of an ancient transcription controlling phosphoswitch became dependent on the relative flux of upstream signals.
Collapse
Affiliation(s)
- Klára Kirsch
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - András Zeke
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - Orsolya Tőke
- Laboratory for NMR Spectroscopy, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - Péter Sok
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - Ashish Sethi
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Anna Sebő
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | | | - Péter Egri
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - Ádám L Póti
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - Paul Gooley
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Isabel Bento
- European Molecular Biology Laboratory, Hamburg, Germany
| | - Anita Alexa
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary
| | - Attila Reményi
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, H-1117, Budapest, Hungary.
| |
Collapse
|
10
|
Torgeson KR, Clarkson MW, Kumar GS, Page R, Peti W. Cooperative dynamics across distinct structural elements regulate PTP1B activity. J Biol Chem 2020; 295:13829-13837. [PMID: 32737198 DOI: 10.1074/jbc.ra120.014652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/30/2020] [Indexed: 12/14/2022] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) is the canonical enzyme for investigating how distinct structural elements influence enzyme catalytic activity. Although it is recognized that dynamics are essential for PTP1B function, the data collected thus far have not resolved whether distinct elements are dynamically coordinated or, alternatively, whether they fulfill their respective functions independently. To answer this question, we performed a comprehensive 13C-methyl relaxation study of Ile, Leu, and Val (ILV) residues of PTP1B, which, because of its substantially increased sensitivity, provides a comprehensive understanding of the influence of protein motions on different time scales for enzyme function. We discovered that PTP1B exhibits dynamics at three distinct time scales. First, it undergoes a distinctive slow motion that allows for the dynamic binding and release of its two most N-terminal helices from the catalytic core. Second, we showed that PTP1B 13C-methyl group side chain fast time-scale dynamics and 15N backbone fast time-scale dynamics are fully consistent, demonstrating that fast fluctuations are essential for the allosteric control of PTP1B activity. Third, and most importantly, using 13C ILV constant-time Carr-Purcell-Meiboom-Gill relaxation measurements experiments, we demonstrated that all four catalytically important loops-the WPD, Q, E, and substrate-binding loops-work in dynamic unity throughout the catalytic cycle of PTP1B. Thus, these data show that PTP1B activity is not controlled by a single functional element, but instead all key elements are dynamically coordinated. Together, these data provide the first fully comprehensive picture on how the validated drug target PTP1B functions.
Collapse
Affiliation(s)
- Kristiane R Torgeson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Michael W Clarkson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA.
| |
Collapse
|
11
|
Abstract
Protein tyrosine phosphatase 1B (PTP1B) is a validated therapeutic target for the treatment of diabetes and obesity. Ertiprotafib is a PTP1B inhibitor that reached the clinical trial stage for the treatment of diabetes. Interestingly, Ertiprotafib reduces the melting temperature of PTP1B in differential scanning fluorimetry (DSF) assays, different from most drugs that increase the stability of their target upon binding. No molecular data on how Ertiprotafib functions has been published. Thus, to gain molecular insights into the mode of action of Ertiprotafib, we used biomolecular NMR spectroscopy to characterize the molecular details of the PTP1B:Ertiprotafib interaction. Our results show that Ertiprotafib induces aggregation of PTP1B in a concentration dependent manner. This shows that the insufficient clinical efficacy and adverse effects caused by Ertiprotafib is due to its tendency to cause aggregation of PTP1B.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, United States of America
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, United States of America
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, United States of America
| |
Collapse
|
12
|
Sok P, Gógl G, Kumar GS, Alexa A, Singh N, Kirsch K, Sebő A, Drahos L, Gáspári Z, Peti W, Reményi A. MAP Kinase-Mediated Activation of RSK1 and MK2 Substrate Kinases. Structure 2020; 28:1101-1113.e5. [PMID: 32649858 DOI: 10.1016/j.str.2020.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/03/2020] [Accepted: 06/22/2020] [Indexed: 11/17/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) control essential eukaryotic signaling pathways. While much has been learned about MAPK activation, much less is known about substrate recruitment and specificity. MAPK substrates may be other kinases that are crucial to promote a further diversification of the signaling outcomes. Here, we used a variety of molecular and cellular tools to investigate the recruitment of two substrate kinases, RSK1 and MK2, to three MAPKs (ERK2, p38α, and ERK5). Unexpectedly, we identified that kinase heterodimers form structurally and functionally distinct complexes depending on the activation state of the MAPK. These may be incompatible with downstream signaling, but naturally they may also form structures that are compatible with the phosphorylation of the downstream kinase at the activation loop, or alternatively at other allosteric sites. Furthermore, we show that small-molecule inhibitors may affect the quaternary arrangement of kinase heterodimers and thus influence downstream signaling in a specific manner.
Collapse
Affiliation(s)
- Péter Sok
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary
| | - Gergő Gógl
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary
| | | | - Anita Alexa
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary
| | - Neha Singh
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary
| | - Klára Kirsch
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary
| | - Anna Sebő
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary
| | - László Drahos
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Budapest, Hungary
| | - Zoltán Gáspári
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, USA
| | - Attila Reményi
- Biomolecular Interactions Research Group, Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja 2., 1117 Budapest, Hungary.
| |
Collapse
|
13
|
Nguyen KT, Moorman R, Kuykendall V, Bura L, Erbe EE, Essig K, Galoux IM, Gentry GM, Kersten S, Kho CC, Kim CH, Kumar GS, Lisowski GT, Manso DL, Ochieng CD, Ritland C, Sriplarich C, Sundquist DL, Tam KC, Vaida M, Weiping G. Determination of N-Octyl Bicycloheptene Dicarboximide, Pyrethrins, and Butylcarbityl 6-Propylpiperonyl Ether in Technical Materials, Concentrates, and Finished Products by Capillary Gas Chromatography: Collaborative Study. J AOAC Int 2020. [DOI: 10.1093/jaoac/81.3.503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
abstract
Nineteen collaborating laboratories (including the authors') analyzed 6 blind, duplicate pairs of various technical materials, pyrethrum extracts, concentrates, and finished products by split injection capillary gas chromatography (GC) with flame ionization detection. This procedure simultaneously quantitates with speed, ease, accuracy, and precision all 6 insecticidal compounds in pyrethrum: pyrethrin I, jasmolin I, cinerin I, pyrethrin II, jasmolin II, and cinerin II, as well as butylcarbityl 6-propylpiperonyl ether (BPE, the predominant compound in technical piperonyl butoxide, also commonly known as piperonyl butoxide) and both the endo and exo isomers of N-octyl bicycloheptene dicarboximide (MGK 264). Repeatability ranged from 4.28 to 7.22% for total pyrethrins, from 2.41 to 7.04% for BPE, and from 2.20 to 4.91 % for total MGK 264. Reproducibility ranged from 5.22 to 9.71 % for total pyrethrins, from 4.37 to 7.04% for BPE, and from 2.66 to 6.01 % for total MGK 264. The capillary GC method for these insecticidal compounds in technical materials, concentrates, and finished products has been adopted first action by AOAC INTERNATIONAL.
Collapse
Affiliation(s)
- Khanh T Nguyen
- Sandoz Agro, Inc., Animal Health Division, 12200 Denton Dr, Dallas, TX 75234
| | - Richard Moorman
- Sandoz Agro, Inc., Animal Health Division, 12200 Denton Dr, Dallas, TX 75234
| | - Virginia Kuykendall
- Sandoz Agro, Inc., Animal Health Division, 12200 Denton Dr, Dallas, TX 75234
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Abstract
Phosphorylation is a ubiquitous posttranslational modification that is essential for the regulation of many cellular processes. The human genome consists of more than 200,000 phosphorylation sites, whose phosphorylation is tightly controlled by ≥500 kinases and ~200 phosphatases. Given the large number of phosphorylation sites and the key role phosphorylation plays in regulating cellular processes, it is essential to characterize the impact of phosphorylation on substrate structure, dynamics, and function. However, a major challenge is the large-scale production of phosphorylated proteins in vitro for these structural, functional, and dynamic studies. Here, we describe an efficient protocol used routinely in our laboratory for the production of phosphorylated proteins. We also describe the methods used for identifying, characterizing, and separating the resulting phosphorylated proteins for subsequent studies.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States.
| |
Collapse
|
15
|
Bertran MT, Mouilleron S, Zhou Y, Bajaj R, Uliana F, Kumar GS, van Drogen A, Lee R, Banerjee JJ, Hauri S, O'Reilly N, Gstaiger M, Page R, Peti W, Tapon N. ASPP proteins discriminate between PP1 catalytic subunits through their SH3 domain and the PP1 C-tail. Nat Commun 2019; 10:771. [PMID: 30770806 PMCID: PMC6377682 DOI: 10.1038/s41467-019-08686-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 01/25/2019] [Indexed: 11/26/2022] Open
Abstract
Serine/threonine phosphatases such as PP1 lack substrate specificity and associate with a large array of targeting subunits to achieve the requisite selectivity. The tumour suppressor ASPP (apoptosis-stimulating protein of p53) proteins associate with PP1 catalytic subunits and are implicated in multiple functions from transcriptional regulation to cell junction remodelling. Here we show that Drosophila ASPP is part of a multiprotein PP1 complex and that PP1 association is necessary for several in vivo functions of Drosophila ASPP. We solve the crystal structure of the human ASPP2/PP1 complex and show that ASPP2 recruits PP1 using both its canonical RVxF motif, which binds the PP1 catalytic domain, and its SH3 domain, which engages the PP1 C-terminal tail. The ASPP2 SH3 domain can discriminate between PP1 isoforms using an acidic specificity pocket in the n-Src domain, providing an exquisite mechanism where multiple motifs are used combinatorially to tune binding affinity to PP1.
Collapse
Affiliation(s)
- M Teresa Bertran
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Stéphane Mouilleron
- Structural Biology - Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
| | - Yanxiang Zhou
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Rakhi Bajaj
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Federico Uliana
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Ganesan Senthil Kumar
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Audrey van Drogen
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Rebecca Lee
- Structural Biology - Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Jennifer J Banerjee
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Simon Hauri
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Nicola O'Reilly
- Peptide Chemistry Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Matthias Gstaiger
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Rebecca Page
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Wolfgang Peti
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
| |
Collapse
|
16
|
Kumar GS, Choy MS, Koveal DM, Lorinsky MK, Lyons SP, Kettenbach AN, Page R, Peti W. Identification of the substrate recruitment mechanism of the muscle glycogen protein phosphatase 1 holoenzyme. Sci Adv 2018; 4:eaau6044. [PMID: 30443599 PMCID: PMC6235537 DOI: 10.1126/sciadv.aau6044] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/15/2018] [Indexed: 05/04/2023]
Abstract
Glycogen is the primary storage form of glucose. Glycogen synthesis and breakdown are tightly controlled by glycogen synthase (GYS) and phosphorylase, respectively. The enzyme responsible for dephosphorylating GYS and phosphorylase, which results in their activation (GYS) or inactivation (phosphorylase) to robustly stimulate glycogen synthesis, is protein phosphatase 1 (PP1). However, our understanding of how PP1 recruits these substrates is limited. Here, we show how PP1, together with its muscle glycogen-targeting (GM) regulatory subunit, recruits and selectively dephosphorylates its substrates. Our molecular data reveal that the GM carbohydrate binding module (GM CBM21), which is amino-terminal to the GM PP1 binding domain, has a dual function in directing PP1 substrate specificity: It either directly recruits substrates (i.e., GYS) or recruits them indirectly by localization (via glycogen for phosphorylase). Our data provide the molecular basis for PP1 regulation by GM and reveal how PP1-mediated dephosphorylation is driven by scaffolding-based substrate recruitment.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Meng S. Choy
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Dorothy M. Koveal
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Michael K. Lorinsky
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Scott P. Lyons
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Arminja N. Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Corresponding author.
| |
Collapse
|
17
|
Abstract
AIM The aim of this study is to analyze and compare the immunohistochemical expression of cathepsin B in primary oral squamous cell carcinoma (OSCC) and recurrent OSCC. MATERIALS AND METHODS A total of 50 cases were studied immunohistochemically for rabbit polyclonal antihuman cathepsin D expression. A total of 10 cases of breast carcinoma were taken as positive controls. Immunohistochemical staining was performed using labeled streptavidin-biotin technique. RESULTS All the 45 cases of OSCC, both primary and recurrent cases included, showed varying grades of cathepsin D immu-noreactivity. Statistical significance at 5% level was observed in cathepsin D expression between the different grades of well, moderate, and poorly differentiated primary squamous cell carcinomas. In the comparison of cathepsin D staining intensity among primary squamous cell carcinomas with and without recurrence, a statistical significance between the groups was observed when the p-value was at 10%, but the same comparison was not significant when the p-value was at 5%. CONCLUSION Cathepsin D expression in primary squamous cell carcinomas with recurrences was very variable as compared with primary squamous cell carcinomas without recurrences. Comparison of cathepsin D expression in primary with their recurrent counterparts showed mostly similar intensity of expression in recurrent carcinomas, thus suggesting its limited usefulness in predicting recurrence. CLINICAL SIGNIFICANCE Although cathepsin D might have shown limited usefulness in predicting cancer recurrence, it, however, is a proven valuable tool to detect the aggressiveness of various other tumors, and if corroborated with a larger sample may hold the key to early, more effective, and more specific treatment modalities for cases of oral cancer also.
Collapse
Affiliation(s)
- Krishnanand P Satelur
- Department of Oral Pathology, Krishnadevaraya College of Dental Sciences, Bengaluru, Karnataka, India, e-mail:
| | - G S Kumar
- Department of Oral Pathology, KSR Institute of Dental Sciences, Tiruchengode, Tamil Nadu, India
| |
Collapse
|
18
|
Reddy VR, Chowdhary N, Kumar GS, Ambareen Z. Bilateral fusion of mandibular primary teeth with partial anodontia of permanent teeth: A report of a rare case. Saudi J Health Sci 2017. [DOI: 10.4103/sjhs.sjhs_43_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
19
|
Abstract
OBJECTIVES To describe aerobic physical activity among middle-aged and older adults by their self-reported cognitive decline and their receipt of informal care for declines in cognitive functioning and most common type of physical activity. DESIGN Cross-sectional study using data from the 2011 Behavioral Risk Factor Surveillance System. SETTING Landline and cellular telephone survey. PARTICIPANTS 93,082 respondents aged 45 years and older from 21 US states in 2011. MEASUREMENTS Subjective cognitive decline (SCD) was defined as experiencing confusion or memory loss that was happening more often or getting worse during the past 12 months. Regular care was defined as always, usually, or sometimes receiving care from family or friends because of SCD. Using the 2008 Physical Activity Guidelines for Americans, respondents were classified as being inactive, insufficiently active, or sufficiently active based on their reported aerobic exercise. We calculated weighted proportions and used chi-square tests for differences across categories by SCD status and receipt of care. We estimated the prevalence ratio (PR) for being inactive, insufficiently active, and sufficiently active using separate log-binomial regression models, adjusting for covariates. RESULTS 12.3% of respondents reported SCD and 23.1% of those with SCD received regular care. 29.6% (95%CI: 28.9-30.4) of respondents without SCD were inactive compared to 37.1% (95%CI: 34.7-39.5) of those with SCD who did not receive regular care and 50.2% (95%CI: 45.2-55.1) of those with SCD who received regular care. 52.4% (95%CI: 51.6-53.2) of respondents without SCD were sufficiently active compared to 46.4% (95%CI: 43.8-49.0) of respondents with SCD and received no regular care and 30.6% (95%CI: 26.1-35.6) of respondents with SCD who received regular care. After adjusting for demographic and health status differences, people receiving regular care for SCD had a significantly lower prevalence of meeting aerobic guidelines compared to people without SCD (PR=0.80, 95%CI: 0.69-0.93, p=0.005). The most prevalent physical activity was walking for adults aged ≥ 45 years old (41-52%) regardless of SCD status or receipt of care. CONCLUSION Overall, the prevalence of inactivity was high, especially among people with SCD. These findings suggest a need to increase activity among middle-aged and older adults, particularly those with SCD who receive care. Examining ways to increase walking, potentially by involving informal caregivers, could be a promising way for people with SCD to reduce inactivity and gain the health benefits associated with meeting physical activity guidelines.
Collapse
Affiliation(s)
- C E Miyawaki
- Christina E Miyawaki, University of Houston, Graduate College of Social Work, 3511 Cullen Blvd. Room 110HA, Houston, TX 77204-4013, USA, PHONE: 713-743-0320, FAX: 713-743-8016,
| | | | | | | |
Collapse
|
20
|
Niranjan KC, Tayaar A, Kumar GS, Krishnapillai R, Hallikeri K, Hunasgi S. Immunohistochemical Expression of Cyclin B1 in Epithelial Hyperplasia, Dysplasia and Oral Squamous Cell Carcinomas - A Comparative Study. J Clin Diagn Res 2016; 10:ZC85-ZC90. [PMID: 27790587 DOI: 10.7860/jcdr/2016/19820.8563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 06/06/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Cyclin B1 is important in the cell cycle progression from G2 to M phase. Cyclin B1 binds to CDC2, which then becomes dephosphorylated and gets relocated to the nucleus, ensuring the transition toward mitosis. AIM Over expression of Cyclin B1, has been reported more recently in breast, colon, prostate, oral and esophageal carcinomas. Thus, the aim of the present study was to examine the expression of Cyclin B1 in hyperplasia, dysplasia and Oral Squamous Cell Carcinomas (OSCC). MATERIALS AND METHODS A total of 64 histopathologically diagnosed cases of epithelial hyperplasias, dysplastic oral epithelium and OSCC were included in the study. Immunohistochemical procedure was carried out using the monoclonal mouse Cyclin B1 antibody (Clone V-152). The Cyclin B1 positive tumor cells counted were expressed as percentage of positive tumor cells. Nuclear and cytoplasmic labeling index (n&cLI) were calculated. The results were tabulated and statistically analyzed by Kruskal Wallis test- One Way ANOVA and Mann Whitney U- test. RESULTS Combined n&cLI was considered only in 28.57% of epithelial hyperplasias, 40.7% of oral epithelial dysplasias and 72% of OSCC showed over expression of Cyclin B1 with p value being 0.029. Cyclin B1 expression was not significantly different between the grades of dysplasia, between the grades of OSCC and between the marginal groups. CONCLUSION The present study demonstrates more than 50% of the study group showing less than 20% of nuclear staining. The importance of such variations within a type of lesion requires further investigation, since Cyclin B1 has proved useful in many studies from esophageal and laryngeal squamous cell carcinoma as a prognostic indicator, an indicator of recurrence and as an indicator for tumor sensitivity to radiotherapy. Further studies are to be extended towards evaluating the role of Cyclin B1 as a prognostic indicator.
Collapse
Affiliation(s)
- Kochli Channappa Niranjan
- Reader, Department of Oral and Maxillofacial Pathology, SDM College of Dental Sciences and Hospital , Dharwad, Karnataka, India
| | - Amsavardani Tayaar
- Professor, Department of Oral and Maxillofacial Pathology, SDM College of Dental Sciences and Hospital , Dharwad, Karnataka, India
| | - G S Kumar
- Principal, Professor and Head of Department, Department of Oral and Maxillofacial Pathology, K.S.R. Institute of Dental Science and Research , Tiruchengode, Tamil Nadu, India
| | - Rekha Krishnapillai
- Professor, Department of Oral and Maxillofacial Pathology, Anoor Dental College , Ernakulam, Kerala, India
| | - Kaveri Hallikeri
- Professor, Department of Oral and Maxillofacial Pathology, SDM College of Dental Sciences and Hospital , Dharwad, Karnataka, India
| | - Santosh Hunasgi
- Professor, Department of Oral and Maxillofacial Pathology, Navodaya Dental College , Raichur, Karnataka, India
| |
Collapse
|
21
|
Kumar GS, Gokhan E, De Munter S, Bollen M, Vagnarelli P, Peti W, Page R. The Ki-67 and RepoMan mitotic phosphatases assemble via an identical, yet novel mechanism. eLife 2016; 5. [PMID: 27572260 PMCID: PMC5005033 DOI: 10.7554/elife.16539] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/16/2016] [Indexed: 12/26/2022] Open
Abstract
Ki-67 and RepoMan have key roles during mitotic exit. Previously, we showed that Ki-67 organizes the mitotic chromosome periphery and recruits protein phosphatase 1 (PP1) to chromatin at anaphase onset, in a similar manner as RepoMan (Booth et al., 2014). Here we show how Ki-67 and RepoMan form mitotic exit phosphatases by recruiting PP1, how they distinguish between distinct PP1 isoforms and how the assembly of these two holoenzymes are dynamically regulated by Aurora B kinase during mitosis. Unexpectedly, our data also reveal that Ki-67 and RepoMan bind PP1 using an identical, yet novel mechanism, interacting with a PP1 pocket that is engaged only by these two PP1 regulators. These findings not only show how two distinct mitotic exit phosphatases are recruited to their substrates, but also provide immediate opportunities for the design of novel cancer therapeutics that selectively target the Ki-67:PP1 and RepoMan:PP1 holoenzymes.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, United States
| | - Ezgi Gokhan
- College of Health and Life Science, Research Institute for Environment, Health and Society, Brunel University London, Uxbridge, United Kingdom
| | - Sofie De Munter
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Paola Vagnarelli
- College of Health and Life Science, Research Institute for Environment, Health and Society, Brunel University London, Uxbridge, United Kingdom
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, United States
| | - Rebecca Page
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, United States
| |
Collapse
|
22
|
Abstract
BACKGROUND Universal pre-discharge assessment of risk for neonatal hyperbilirubinaemia is recommended by the American Academy of Pediatrics. A common algorithm is universal transcutaneous bilirubin (TcB) screening, followed by confirmatory total serum bilirubin (TSB) testing for results which cause concern. There is a paucity of data on the feasibility of TcB screening in low-income settings. OBJECTIVES To evaluate the acceptability and feasibility of implementing universal TcB screening at a resource-limited hospital in rural India, and to determine if it was associated with increased recognition of high-risk hyperbilirubinaemia. METHODS In December 2012 at Vivekananda Memorial Hospital, Karnataka, India, universal TcB screening at 24-48 hours of life was implemented, with TSB estimated if TcB was >75th percentile for age. The proportion of families that provided consent and the proportion of infants who underwent TcB and TSB testing were calculated. The rates of phototherapy pre- and post-implementation and the rate of high-risk hyperbilirubinaemia (TSB >95th percentile for age) post-implementation among infants ≥ 35 weeks gestation were determined. RESULTS Parents of 568 of 660 (86%) eligible infants consented to participation. All of these infants were screened with TcB. The proportion who had TSB testing was similar in the pre- (6%) and post-implementation (7%) periods. The rate of phototherapy was not significantly different after implementation (2% vs 3%). Five cases of high-risk hyperbilirubinaemia were identified post-implementation. CONCLUSIONS The study demonstrates the acceptability and feasibility of universal TcB screening at a resource-limited hospital in rural India. In settings in which early post-discharge follow-up cannot be assured, TcB can play a valuable role in identifying infants who need evaluation.
Collapse
Affiliation(s)
- Melissa C Morgan
- a Department of Paediatrics , University of California , San Francisco , USA
| | - G S Kumar
- b Departments of Paediatrics , Vivekananda Memorial Hospital , Saragur , India
| | - Sunitha V Kaiser
- a Department of Paediatrics , University of California , San Francisco , USA
| | - Sridevi Seetharam
- c Department of Pathology , Vivekananda Memorial Hospital , Saragur , India
| | - Theodore D Ruel
- a Department of Paediatrics , University of California , San Francisco , USA
| |
Collapse
|
23
|
Clark MD, Kumar GS, Marcum R, Luo Q, Zhang Y, Radhakrishnan I. Molecular Basis for the Mechanism of Constitutive CBP/p300 Coactivator Recruitment by CRTC1-MAML2 and Its Implications in cAMP Signaling. Biochemistry 2015; 54:5439-46. [PMID: 26274502 DOI: 10.1021/acs.biochem.5b00332] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cyclic AMP response element-binding protein (CREB) is a signal-dependent transcription factor that exerts its positive effects on gene transcription of a broad range of genes by recruiting coactivators, including CREB-binding protein (CBP), its paralog, p300, and the family of CRTC (CREB-regulated transcriptional coactivators) proteins. Whereas recruitment of CBP/p300 is dependent on CREB phosphorylation at Ser133, recruitment of CRTCs is not. Here we describe how both mechanisms could concurrently drive transcription of CREB targets in a subset of head and neck cancers featuring chromosomal translocations that fuse portions of CRTC1 and CRTC3 genes with that of the Mastermind-like transcriptional coactivator MAML2. We show that a peptide derived from transactivation domain 1 (TAD1) of MAML2 binds to the CBP KIX domain with micromolar affinity. An ∼20-residue segment within this peptide, conserved in MAML2 orthologs and paralogs, binds directly to a KIX surface previously shown to bind to MLL1. The 20-residue MAML2 segment shares sequence similarity with MLL1, especially at those positions in direct contact with KIX, and like MLL1, the segment is characterized by the presence of an ∼10-residue helix. Because CRTC1/3-MAML2 fusion proteins are constitutively nuclear, like CREB, our results suggest constitutive recruitment of CBP/p300 to CREB targets that could be further enhanced by signals that cause CREB Ser133 phosphorylation.
Collapse
Affiliation(s)
- Michael David Clark
- Department of Molecular Biosciences, Northwestern University , 2205 Tech Drive, Evanston, Illinois 60208-3500, United States
| | - Ganesan Senthil Kumar
- Department of Molecular Biosciences, Northwestern University , 2205 Tech Drive, Evanston, Illinois 60208-3500, United States
| | - Ryan Marcum
- Department of Molecular Biosciences, Northwestern University , 2205 Tech Drive, Evanston, Illinois 60208-3500, United States
| | - Qianyi Luo
- Department of Molecular Biosciences, Northwestern University , 2205 Tech Drive, Evanston, Illinois 60208-3500, United States
| | - Yongbo Zhang
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Ishwar Radhakrishnan
- Department of Molecular Biosciences, Northwestern University , 2205 Tech Drive, Evanston, Illinois 60208-3500, United States
| |
Collapse
|
24
|
Sameera Devi C, Kumar GS, Prasad G. Spectroscopic and electrical studies on Nd(3+), Zr(4+) ions doped nano-sized BaTiO3 ferroelectrics prepared by sol-gel method. Spectrochim Acta A Mol Biomol Spectrosc 2015; 136 Pt B:366-372. [PMID: 25448941 DOI: 10.1016/j.saa.2014.09.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/24/2014] [Accepted: 09/18/2014] [Indexed: 06/04/2023]
Abstract
Lead free ferroelectric ceramics in the form of Ba(1-3x)Nd(2x)Ti(1-y)ZryO3 ((where x=0.025, y=0 (BT1), 0.025 (BT2), 0.05 (BT3)) were prepared using sol-gel method. The surface morphology and the orientation of grains of the present ceramics were examined using Field Emission Scanning Electron Microscope (FESEM) images. The effect of Nd(3+), Zr(4+) ions content on the BaTiO3 was studied using Raman and Fourier Transform Infrared (FTIR) spectroscopies. From the Raman analysis the band observed at ∼838 cm(-1) was attributed due to the presence of Nd(3+)-barium vacancy pairs. The FTIR studies suggested that the addition of Nd(3+) ions in A-site of BaTiO3 (ABO3) perovskite create lattice distortion by forming A-site vacancies and Zr(4+) ions in B-site of BaTiO3 induce the lattice distortion by forming ZrO6 octahedra in the place of TiO6 octahedra. Dielectric measurements of the samples were done at different frequencies from RT-150°C. Charge transportation phenomenon is explained using DC conductivity, which is found to increase with temperature.
Collapse
Affiliation(s)
- Ch Sameera Devi
- Materials Research Laboratory, Department of Physics, Osmania University, Hyderabad 500 007, India
| | - G S Kumar
- Materials Research Laboratory, Department of Physics, Osmania University, Hyderabad 500 007, India
| | - G Prasad
- Materials Research Laboratory, Department of Physics, Osmania University, Hyderabad 500 007, India.
| |
Collapse
|
25
|
Kumar GS, Zettl H, Page R, Peti W. Structural basis for the regulation of the mitogen-activated protein (MAP) kinase p38α by the dual specificity phosphatase 16 MAP kinase binding domain in solution. J Biol Chem 2013; 288:28347-56. [PMID: 23926106 PMCID: PMC3784751 DOI: 10.1074/jbc.m113.499178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 08/01/2013] [Indexed: 12/11/2022] Open
Abstract
Mitogen-activated protein kinases (MAPKs) fulfill essential biological functions and are key pharmaceutical targets. Regulation of MAPKs is achieved via a plethora of regulatory proteins including activating MAPKKs and an abundance of deactivating phosphatases. Although all regulatory proteins use an identical interaction site on MAPKs, the common docking and hydrophobic pocket, they use distinct kinase interaction motif (KIM or D-motif) sequences that are present in linear, peptide-like, or well folded protein domains. It has been recently shown that a KIM-containing MAPK-specific dual specificity phosphatase DUSP10 uses a unique binding mode to interact with p38α. Here we describe the interaction of the MAPK binding domain of DUSP16 with p38α and show that despite belonging to the same dual specificity phosphatase (DUSP) family, its interaction mode differs from that of DUSP10. Indeed, the DUSP16 MAPK binding domain uses an additional helix, α-helix 4, to further engage p38α. This leads to an additional interaction surface on p38α. Together, these structural and energetic differences in p38α engagement highlight the fine-tuning necessary to achieve MAPK specificity and regulation among multiple regulatory proteins.
Collapse
Affiliation(s)
| | - Heiko Zettl
- From the Departments of Molecular Pharmacology, Physiology and Biotechnology
| | - Rebecca Page
- Molecular Biology, Cell Biology, and Biochemistry, and
| | - Wolfgang Peti
- From the Departments of Molecular Pharmacology, Physiology and Biotechnology
- Chemistry, Brown University, Providence, Rhode Island 02912
| |
Collapse
|
26
|
Francis DM, Kumar GS, Koveal D, Tortajada A, Page R, Peti W. The differential regulation of p38α by the neuronal kinase interaction motif protein tyrosine phosphatases, a detailed molecular study. Structure 2013; 21:1612-23. [PMID: 23932588 PMCID: PMC3769431 DOI: 10.1016/j.str.2013.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/24/2013] [Accepted: 07/02/2013] [Indexed: 10/26/2022]
Abstract
The MAP kinase p38α is essential for neuronal signaling. To better understand the molecular regulation of p38α we used atomistic and molecular techniques to determine the structural basis of p38α regulation by the two neuronal tyrosine phosphatases, PTPSL/PTPBR7 (PTPRR) and STEP (PTPN5). We show that, despite the fact that PTPSL and STEP belong to the same family of regulatory proteins, they interact with p38α differently and their distinct molecular interactions explain their different catalytic activities. Although the interaction of PTPSL with p38α is similar to that of the previously described p38α:HePTP (PTPN7) complex, STEP binds and regulates p38α in an unexpected manner. Using NMR and small-angle X-ray scattering data, we generated a model of the p38α:STEP complex and define molecular differences between its resting and active states. Together, these results provide insights into molecular regulation of p38α by key regulatory proteins.
Collapse
Affiliation(s)
- Dana May Francis
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence RI, 02912, USA
| | - Ganesan Senthil Kumar
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence RI, 02912, USA
| | - Dorothy Koveal
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence RI, 02912, USA
| | - Antoni Tortajada
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence RI, 02912, USA
| | - Rebecca Page
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence RI, 02912, USA
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence RI, 02912, USA
- Department of Chemistry, Brown University, Providence RI, 02912, USA
| |
Collapse
|
27
|
Kumar GS, Chang W, Xie T, Patel A, Zhang Y, Wang GG, David G, Radhakrishnan I. Sequence requirements for combinatorial recognition of histone H3 by the MRG15 and Pf1 subunits of the Rpd3S/Sin3S corepressor complex. J Mol Biol 2012; 422:519-31. [PMID: 22728643 DOI: 10.1016/j.jmb.2012.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 06/07/2012] [Accepted: 06/08/2012] [Indexed: 01/05/2023]
Abstract
The transcriptional output at a genomic locus in eukaryotes is determined, in part, by the pattern of histone modifications that are read and interpreted by key effector proteins. The histone deacetylase activity of the evolutionarily conserved Rpd3S/Sin3S complex is crucial for suppressing aberrant transcription from cryptic start sites within intragenic regions of actively transcribed genes. Precise targeting of the complex relies on the chromatin binding activities of the MRG15 (MRG stands for mortality factor on chromosome 4 related gene) and Pf1 subunits. Whereas the molecular target of the MRG15 chromodomain (CD) has been suggested to be H3K36me(2/3), the precise molecular target of the Pf1 plant homeodomain 1 (PHD1) has remained elusive. Here, we show that Pf1 PHD1 binds preferentially to the unmodified extreme N-terminus of histone H3 (H3K4me(0)) but not to H3K4me(2/3), which are enriched in the promoter and 5' regions of genes. Unlike previously characterized CD and PHD domains that bind to their targets with micromolar affinity, both MRG15 CD and Pf1 PHD1 bind to their targets with >100 μM affinity, offering an explanation for why both MRG15 CD and Pf1 PHD1 domains are required to target the Rpd3S/Sin3S complex to chromatin. Our results also suggest that bivalency, rather than cooperativity, is the operative mechanism by which Pf1 and MRG15 combine to engage H3 in a biologically significant manner. Finally, the studies reveal an unanticipated role of Pf1 PHD1 in engaging the MRG15 MRG domain, albeit in a Pf1 MRG-binding-domain-dependent manner, implying a key role for the MRG15 MRG-Pf1 MBD interaction in chromatin targeting of the Rpd3S/Sin3S complex.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Xie T, Graveline R, Kumar GS, Zhang Y, Krishnan A, David G, Radhakrishnan I. Structural basis for molecular interactions involving MRG domains: implications in chromatin biology. Structure 2012; 20:151-60. [PMID: 22244764 DOI: 10.1016/j.str.2011.10.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/12/2011] [Accepted: 10/15/2011] [Indexed: 11/30/2022]
Abstract
MRG15 is a member of the mortality family of transcription factors that targets a wide variety of multiprotein complexes involved in transcription regulation, DNA repair, and alternative splicing to chromatin. The structure of the apo-MRG15 MRG domain implicated in interactions with diverse proteins has been described, but not in complex with any of its targets. Here, we structurally and functionally characterize the interaction between MRG15 and Pf1, two constitutively associated subunits of the histone deacetylase-associated Rpd3S/Sin3S corepressor complex. The MRG domain adopts a structure reminiscent of the apo state, whereas the Pf1 MRG-binding domain engages two discrete hydrophobic surfaces on the MRG domain via a bipartite motif comprising an α-helix and a segment in an extended conformation, both of which are critical for high-affinity interactions. Multiple MRG15 interactors share an FxLP motif in the extended segment, but equivalent sequence/helical motifs are not readily evident, implying potential diversity in MRG-recognition mechanisms.
Collapse
Affiliation(s)
- Tao Xie
- Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA
| | | | | | | | | | | | | |
Collapse
|
29
|
Kumar GS, Kumar BSP. Stability-Indicating RP-HPLC Method for Determination of Tamsulosin HCL in Pharmaceutical Dosage Form. J Basic Clin Pharm 2012; 3:255-60. [PMID: 24826033 PMCID: PMC3979258 DOI: 10.4103/0976-0105.103817] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/02/2012] [Indexed: 12/04/2022] Open
Abstract
A selective, specific and sensitive stability-indicating high-performance liquid chromatographic method was developed and validated for the determination of Tamsulosin in in pharmaceutical dosage forms. Celecoxib was used as Internal Standard (IS). The chromatographic conditions comprised of a reversed-phase Lichrocart / Lichrosphere C18 column (250 × 4.0 mm packed with 5) with mobile phase consisting of a mixture of Acetonitrile: T.D.W. in the ratio (40: 60). Flow rate was 0.8 mL / min. Detection was carried out at 275 nm. The retention time of Tamsulosin HCl and Celecoxib were found to be 1.608 and 2.767min respectively and the linear regression analysis data for the calibration plots showed good linear relationship in the concentration range 1 - 200 g/mL. The value of correlation coefficient, slope and intercept were, 0.9995, 0.7453 and 0.4584, respectively. Tamsulosin HCl was subjected to stress conditions of degradation in aqueous solutions including acidic, alkaline, oxidation, photolysis and thermal degradation. The developed method was validated with regard to linearity, accuracy, precision, selectivity and robustness and the method was found to be precise, accurate, linear and specific. The method was employed successfully for identification and determination of Tamsulosin in pharmaceutical preparations.
Collapse
Affiliation(s)
- G S Kumar
- Department of Pharmaceutical Analysis and Quality Assurance, GITAM Institute of Pharmacy, GITAM University, Visakhapatnam - 530045, India
| | - B Sai Pavan Kumar
- Department of Pharmaceutical Analysis and Quality Assurance, GITAM Institute of Pharmacy, GITAM University, Visakhapatnam - 530045, India
| |
Collapse
|
30
|
Sivaranjini Y, Angadi PV, Kumar GS. Immuno-histochemical evaluation of Cathepsin D in malignant salivary gland carcinomas. Gulf J Oncolog 2012:38-44. [PMID: 22227544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2011] [Indexed: 05/31/2023]
Abstract
OBJECTIVE Cathepsin D is a lysosomal acid protease secreted in increased levels in several malignancies. However, its role in salivary gland tumors has not been studied extensively. The present study aims to assess the expression of Cathepsin D in malignant salivary gland tumors and to compare its expression in these tumors. STUDY DESIGN A total of 30 cases of malignant salivary gland carcinomas which included 16 cases of adenoid cystic carcinoma (ACC), 9 cases of mucoepidermoid carcinoma (MEC), and 5 cases of polymorphous low grade adenocarcinoma (PLGA) were evaluated immunohistochemically using anti-Cathepsin D antibody. RESULT All the cases showed positivity (100%) for Cathepsin D with intense expression noted in ACC and MEC as compared to PLGA. Comparison of these tumors revealed statistical significant difference in expression between ACC and PLGA. CONCLUSION Intense expression of Cathepsin D in high grade carcinomas may be a marker for invasive potential and aggressive behavior.
Collapse
Affiliation(s)
- Y Sivaranjini
- Dept of Oral & Maxillofacial Pathology and Microbiology, KLEVK Institute of Dental Sciences and Hospital, Belgaum, Karnataka, India
| | | | | |
Collapse
|
31
|
Seetharam S, Balasubramaniam B, Kumar GS, Seetharam MR. Pains and gains of rural health practice: lessons books never taught. Narrat Inq Bioeth 2012; 2:106-109. [PMID: 24406830 DOI: 10.1353/nib.2012.0039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
|
32
|
Abstract
Odontogenic cysts and tumors are distinct entities and quite a common occurrence in the jaw bones. The lining of odontogenic cysts shows a potential for neoplastic transformation to non odontogenic malignancies like squamous cell carcinoma and mucoepidermoid carcinoma, and odontogenic tumors like ameloblastoma and adenoamatoid odontogenic tumor (AOT). AOT is a benign, epithelial odontogenic tumor, common site being the anterior maxilla. Its origin from a dentigerous cyst and in the mandible is rare. A case of an AOT arising from a dentigerous cyst associated with an impacted permanent mandibular left lateral incisor is reported.
Collapse
Affiliation(s)
- Zama Moosvi
- Department of Oral Pathology, HKE'S S Nijalingappa Institute of Dental Sciences, Gulbarga, India
| | | | | |
Collapse
|
33
|
Abstract
Congenital heart defects are known to be associated with facial dysmorphism and other congenital anomalies. Oculo-facio-cardio-dental (OFCD) syndrome is one such rare multiple congenital anomaly syndrome inherited as an X-linked dominant condition characterized by congenital cataracts, multiple minor facial dysmorphic features, congenital heart defects and dental anomalies. It is unrecognized by many medical and dental professionals. Only 21 cases have been reported so far. This syndrome is often misrecognized as rubella embryopathy because of association of congenital cataract with cardiac anomalies. It is usually the orthodontists who diagnose the syndrome based on typical findings on dental panoramic radiographs. But we suspected our patient to be having OFCD syndrome based on typical facial dysmorphism, ocular and cardiac defects, and finally it was confirmed after noticing typical dental radiographic findings.
Collapse
Affiliation(s)
- Sudha Rudrappa
- Department of Pediatrics, Mysore Medical College and Research Institute, Mysore, Karnataka, India
| | | | | |
Collapse
|
34
|
Manjunatha BS, Kumar GS, Raghunath V. Immunohistochemical expression of Bcl-2 in benign and malignant salivary gland tumors. Med Oral Patol Oral Cir Bucal 2011; 16:e503-7. [PMID: 21196881 DOI: 10.4317/medoral.16.e503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Accepted: 05/03/2010] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The present study was undertaken to assess and compare the immunohistochemical expression of Bcl-2 in selected benign and malignant salivary gland tumors. STUDY DESIGN A total of 50 cases of buffered formalin-fixed, paraffin embedded tissues of previously diagnosed cases of benign and malignant salivary gland tumors from the archives of Department of Oral and Maxillofacial Pathology and Microbiology, SDM College of Dental Sciences and Hospital, Dharwad, India, were taken for the study. The immunohistochemical staining procedure was performed using monoclonal anti Bcl-2 antibody, as directed by the manufacturer. RESULTS Thirty six cases (72%) out of 50 cases showed a positive expression for Bcl-2. Benign salivary gland tumors showed a positive expression in 8 out of 14 cases (~57%) and malignant salivary gland tumors in 28 out of 36 cases (~78%). The staining was intense in the normal lymph node, which is used as a positive control. Bcl-2 expression was seen in both benign and in malignant salivary gland tumors taken for the study except in "canalicular adenoma". CONCLUSION The immunohistochemical expression of Bcl-2 was greater and more intense in malignant salivary gland neoplasms, suggesting a high survival rate of tumor cells in malignant neoplasms.
Collapse
Affiliation(s)
- B S Manjunatha
- K M Shah Dental College & Hospital, Pipariya-391760, Waghodia (T), Vadodara (D), Gujarat (S), India.
| | | | | |
Collapse
|
35
|
Manjunatha BS, Kumar GS, Raghunath V. Immunohistochemical expression of Bcl-2 in benign and malignant salivary gland tumors. Med Oral Patol Oral Cir Bucal 2011. [PMID: 21196881 DOI: 10.4317/medoral.16.e503.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES The present study was undertaken to assess and compare the immunohistochemical expression of Bcl-2 in selected benign and malignant salivary gland tumors. STUDY DESIGN A total of 50 cases of buffered formalin-fixed, paraffin embedded tissues of previously diagnosed cases of benign and malignant salivary gland tumors from the archives of Department of Oral and Maxillofacial Pathology and Microbiology, SDM College of Dental Sciences and Hospital, Dharwad, India, were taken for the study. The immunohistochemical staining procedure was performed using monoclonal anti Bcl-2 antibody, as directed by the manufacturer. RESULTS Thirty six cases (72%) out of 50 cases showed a positive expression for Bcl-2. Benign salivary gland tumors showed a positive expression in 8 out of 14 cases (~57%) and malignant salivary gland tumors in 28 out of 36 cases (~78%). The staining was intense in the normal lymph node, which is used as a positive control. Bcl-2 expression was seen in both benign and in malignant salivary gland tumors taken for the study except in "canalicular adenoma". CONCLUSION The immunohistochemical expression of Bcl-2 was greater and more intense in malignant salivary gland neoplasms, suggesting a high survival rate of tumor cells in malignant neoplasms.
Collapse
Affiliation(s)
- B S Manjunatha
- K M Shah Dental College & Hospital, Pipariya-391760, Waghodia (T), Vadodara (D), Gujarat (S), India.
| | | | | |
Collapse
|
36
|
Kumar GS, Xie T, Zhang Y, Radhakrishnan I. Solution structure of the mSin3A PAH2-Pf1 SID1 complex: a Mad1/Mxd1-like interaction disrupted by MRG15 in the Rpd3S/Sin3S complex. J Mol Biol 2011; 408:987-1000. [PMID: 21440557 DOI: 10.1016/j.jmb.2011.03.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 03/18/2011] [Accepted: 03/18/2011] [Indexed: 10/18/2022]
Abstract
Histone deacetylation constitutes an important mechanism for silencing genes. The histone-deacetylase-associated mammalian Rpd3S/Sin3S corepressor complex plays key roles in repressing aberrant gene transcription from cryptic transcription initiation sites and in mitigating RNA polymerase II progression in intragenic regions of actively transcribed genes. The Sin3 corepressor functions as a molecular adaptor linking histone deacetylases on the one hand, with the chromatin targeting subunits Pf1 and MRG15 on the other. Pf1 also functions as an adaptor by interacting with MRG15 and engaging in multivalent interactions with Sin3 targeting among other domains the two N-terminal paired amphipathic helix (PAH) domains that serve as sites of interaction with sequence-specific DNA-binding transcription factors. Here, we structurally and functionally evaluate the interaction between the PAH2 domain of mSin3A and the Sin3 interaction domain 1 (SID1) motif of Pf1 and find the structural aspects to be reminiscent of the interaction between the Mad1/Mxd1 transcription factor and Sin3. Pf1 residues within a highly conserved sequence motif immediately C-terminal to SID1 appear not to be important for the interaction with Sin3 PAH2. Unexpectedly, the MRG15 subunit competes, rather than collaborates, with Sin3 for the Pf1 segment encompassing the two conserved motifs, implying competition between two subunits for another subunit of the same chromatin-modifying complex.
Collapse
Affiliation(s)
- Ganesan Senthil Kumar
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208-3500, USA
| | | | | | | |
Collapse
|
37
|
Santhiya ST, Kumar GS, Sudhakar P, Gupta N, Klopp N, Illig T, Söker T, Groth M, Platzer M, Gopinath PM, Graw J. Molecular analysis of cataract families in India: new mutations in the CRYBB2 and GJA3 genes and rare polymorphisms. Mol Vis 2010; 16:1837-47. [PMID: 21031021 PMCID: PMC2956670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 09/06/2010] [Indexed: 10/27/2022] Open
Abstract
PURPOSE The aim of the study was to resolve the genetic etiology in families having inherited cataracts. METHODS Families afflicted with congenital/childhood cataracts were registered in Chennai and Orissa (India). Blood samples were collected from the probands and available family members. Selected functional candidate genes were amplified by polymerase chain reaction (PCR) and characterized by direct sequencing. Putative mutations were confirmed in healthy controls. RESULTS We observed interesting new polymorphisms of ethnic specificity, some of frequent nature, such as a 3-bp deletion in intron 3 of CRYBB2 (encoding βB2-crystallin) and IVS1+9 c>t variation in HSF4 (encoding heat-shock factor 4). Some rare single nucleotide polymorphisms (SNPs) co-segregate with the respective phenotype such as IVS3+120c>a of CRYBB2, while M44V of CRYGD (encoding γD-crystallin), although found in association with blue dot opacity was seen in a few healthy controls too. We identified two new mutations co-segregating along with the respective cataract phenotype within the families that were not seen in healthy controls from India or Germany. These include two missense mutations; one in GJA3 (encoding gap junction protein α3, which is also referred to as connexin 46); the mutation affects codon 19 (T19M), and the corresponding phenotype is a posterior-polar cataract. The other missense mutation affects CRYBB2 (W59C; total cataract). Additionally, a cDNA variation (G54A) identified in a zonular cataract affects a highly conserved splice site of CRYBB2. This mutation, however, showed reduced penetrance in the family, which might be explained by different molecular consequences in the affected family members: nonsense-mediated decay of the mutated mRNA might have no clinical phenotype in heterozygotes, whereas the translation of the mutated mRNA is predicted to lead to a small hybrid protein (consisting of 16 amino acids of the βB2-crystallin and 18 new amino-acids), which might have a dominant-negative function in the lens. CONCLUSIONS This report identifies in families with childhood cataract some new alleles, which may be considered as causative for cataracts. Furthermore, we report some geographically restricted rare polymorphic sites, whose significance might be considered in some context as modifiers or alleles in sensitizing ocular lens toward cataractogenesis.
Collapse
Affiliation(s)
- Sathiyavedu T. Santhiya
- Dr. ALM Postgraduate Institute of Basic Medical Sciences, Department of Genetics, University of Madras, Taramani, Chennai, India
| | - Ganesan Senthil Kumar
- Dr. ALM Postgraduate Institute of Basic Medical Sciences, Department of Genetics, University of Madras, Taramani, Chennai, India
| | - Pridhvi Sudhakar
- Regional Institute of Ophthalmology, Government Eye Hospital, Egmore, Chennai, India
| | - Navnit Gupta
- JPM Rotary Eye Hospital and Research Institute, Cuttack, Orissa, India
| | - Norman Klopp
- Helmholtz Center Munich - German Research Center for Environmental Health, Institute of Epidemiology, D-85764 Neuherberg, Germany
| | - Thomas Illig
- Helmholtz Center Munich - German Research Center for Environmental Health, Institute of Epidemiology, D-85764 Neuherberg, Germany
| | - Torben Söker
- Helmholtz Center Munich - German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
| | - Marco Groth
- Leibniz Institute for Age Research - Fritz Lipmann Institute, Genome Analysis Laboratory, D-07745 Jena, Germany
| | - Matthias Platzer
- Leibniz Institute for Age Research - Fritz Lipmann Institute, Genome Analysis Laboratory, D-07745 Jena, Germany
| | | | - Jochen Graw
- Helmholtz Center Munich - German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
| |
Collapse
|
38
|
Hanning I, Donoghue DJ, Jarquin R, Kumar GS, Aguiar VF, Metcalf JH, Reyes-Herrera I, Slavik M. Campylobacter biofilm phenotype exhibits reduced colonization potential in young chickens and altered in vitro virulence. Poult Sci 2009; 88:1102-7. [PMID: 19359701 DOI: 10.3382/ps.2008-00307] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In this study, we evaluated the ability of different Campylobacter phenotypes (biofilm versus planktonic) to colonize young poultry. It has been suggested that a persistent Campylobacter biofilm reservoir may be involved in the initial contamination of poultry flocks. Campylobacter jejuni cultured adherent to agar was utilized as the biofilm model and C. jejuni cultured in broth was evaluated as the planktonic model. In 2 independent trials, 1-d-old broiler chicks were given 1 of 3 treatments: 1) 10(5) cfu.mL(-1) of C. jejuni cultured in broth, 2) 10(5) cfu.mL(-1) of C. jejuni cultured adherent to agar, or 3) no C. jejuni (negative control). Cecal contents of all birds were evaluated by culturing 12 d after the initial challenge with C. jejuni. In both trials, birds challenged with C. jejuni cultured in broth had approximately 3 to 4 log higher cecal Campylobacter concentration than birds challenged with C. jejuni cultured adherent to agar. Using 2 cell lines (INT 407 and DF1), virulence of C. jejuni cultured in broth versus adherent to agar also was evaluated by challenging monolayers of eukaryotic cells with 1 of 3 treatments: 1) 10(5) cfu.mL(-1) of C. jejuni cultured in broth, 2) 10(5) cfu.mL(-1) of C. jejuni cultured adherent to agar, or 3) no C. jejuni (negative control). The virulence study also showed differences of C. jejuni cultured in broth or agar in attachment and invasion abilities to tissue culture cells, but differences were not as consistent as with the chick colonization study. This study indicates that phenotype may play a role in colonization of chickens and virulence by C. jejuni.
Collapse
Affiliation(s)
- I Hanning
- Department of Poultry Science, University of Arkansas, Fayetteville 72701, USA.
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Umachigi SP, Jayaveera KN, Ashok Kumar CK, Kumar GS, Vrushabendra swamy BM, Kishore Kumar DV. Studies on Wound Healing Properties of Quercus infectoria. TROP J PHARM RES 2008. [DOI: 10.4314/tjpr.v7i1.14677] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
40
|
Manjunatha BS, Kumar GS, Raghunath V. Histochemical and polarization microscopic study of two cases of vegetable/pulse granuloma. Indian J Dent Res 2008. [PMID: 18245929 DOI: 10.4103/0970-9290.38937.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Vegetable granuloma (VG) or pulse granuloma (PG) results from the implantation of food particles of plant or vegetable origin. It is usually seen in the periapical or in the sulcus areas. These lesions have been described as a distinct entity and classified into central and peripheral lesions according to the location. Central lesions are asymptomatic, whereas peripheral lesions present as painless sub-mucosal swellings. Many authors have postulated that food particles in VG or PG get implanted and are rapidly digested, and sometimes partly get altered by host responses. The cellulose part of plant foods being indigestible persists in the form of hyaline material, whereas the starch matter gets digested. This cellulose moiety invokes chronic granulomatous response.
Collapse
Affiliation(s)
- B S Manjunatha
- Dept of Oral Pathology, SJM Dental College and Hospital, Chitradurga, Karnataka, India.
| | | | | |
Collapse
|
41
|
Prabhu S, Angadi P, Kumar GS, Vandana R, Rekha K. Recurrent cystic hygroma with calcification in an adult. J Oral Maxillofac Pathol 2008. [DOI: 10.4103/0973-029x.44584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
42
|
Manjunatha BS, Kumar GS, Raghunath V. Histochemical and polarization microscopic study of two cases of vegetable/pulse granuloma. Indian J Dent Res 2008; 19:74-7. [DOI: 10.4103/0970-9290.38937] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
43
|
Kumar GS, Jayaveera KN, Kumar CK, Sanjay UP, Swamy BM, Kumar DV. Antimicrobial effects of Indian medicinal plants against acne-inducing bacteria. TROP J PHARM RES 2007. [DOI: 10.4314/tjpr.v6i2.14651] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
44
|
Umachigi SP, Kumar GS, Jayaveera K, Kishore KDV, Ashok KCK, Dhanapal R. Antimicrobial, wound healing and antioxidant activities of Anthocephalus cadamba. Afr J Tradit Complement Altern Med 2007; 4:481-7. [PMID: 20161916 PMCID: PMC2816507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Anthocephalus cadamba (Roxb.) Miq. Syn A. chinensis (Lamk) A. Rich (Rubiaceae) is ethnomedicinally widely used in the form of paste by tribe in western Ghats for treating skin diseases. In this context, antimicrobial potential of A. cadamba against a wide range of microorganisms was studied. To validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied, besides antioxidant activity to understand the mechanism of wound healing. The alchoholic and aqueous extract of this plant showed significant antibacterial and antifungal activity against almost all the organisms: Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and four fungi Candida albicans, Trichophyton rubrum--dermatophyte fungi, Aspergillus niger, Aspergillus flavus and Aspergillus nidulans--systemic fungi, with especially good activity against the dermatophyte (Trichophyton rubrum) and some infectious bacteria (Escherichia coli, Proteus mirabilis and Staphylococcus aureus) with an MIC of 2.5 microg/disc. The results show that A. cadamba extract has potent wound healing capacity as shown from the wound contraction and increased tensile strength. The results also indicated that A. cadamba extract possesses potent antioxidant activity by inhibiting lipid peroxidation and increase in the superoxide dismutase (SOD) and catalase activity.
Collapse
Affiliation(s)
- Sanjay Prahalad Umachigi
- Rural College of Pharmacy, D.S. Road, PO Box-10, Devanahalli-562110, Bangalore Rural Dist, Karnataka, India.
| | | | | | | | | | | |
Collapse
|
45
|
Kumar GS, Ramasamy P, Sikdar SK, Sarma SP. Overexpression, purification, and pharmacological activity of a biosynthetically derived conopeptide. Biochem Biophys Res Commun 2005; 335:965-72. [PMID: 16115470 DOI: 10.1016/j.bbrc.2005.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Accepted: 08/02/2005] [Indexed: 11/17/2022]
Abstract
A high yielding fusion protein system based on the protein cytochrome b(5) has been used for the production of novel 13-residue acyclic conopeptide. This peptide, Mo1659, can be liberated from the carrier protein using CNBr cleavage and subsequent purification using RP-HPLC methods. The yield of isotopically enriched peptides is high, ranging from 3 to 4mg of purified peptide from a 500ml culture, indicating that this system can be widely used for peptide production. Biosynthetic Mo1659 is active on non-inactivating K(+) channel much like the natural Mo1659, despite the absence of C-terminal amidation. Heteronuclear NMR studies show that the peptide exists in a conformational equilibrium involving proline-10. To our knowledge this is the first report of the production of an isotopically (15)N/(13)C-enriched conopeptide.
Collapse
|
46
|
Mitra A, Chakrabarti KS, Shahul Hameed MS, Srinivas KV, Senthil Kumar G, Sarma SP. High level expression of peptides and proteins using cytochrome b5 as a fusion host. Protein Expr Purif 2005; 41:84-97. [PMID: 15802225 DOI: 10.1016/j.pep.2004.12.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 12/13/2004] [Indexed: 11/20/2022]
Abstract
A novel fusion protein system based on the highly soluble heme-binding domain of cytochrome b5 has been designed. The ability of cytochrome b5 to increase the levels of expression and solubility of target proteins has been tested by expressing several proteins and peptides, viz., alpha hemoglobin stabilizing protein, the regulatory subunits of acetohydroxy acid synthase I (ilvM) and II (ilvN), the carboxy terminal domains of mouse neuronal kinesin and pantothenate synthatase, two peptide toxins from cone snails, and the inactivation gate from the brain voltage gated sodium channel, NaV1.2. The fusion protein system has been designed to incorporate protease cleavage sites for commonly used proteases, viz., enterokinase, Factor Xa, and Tobacco etch virus protease. Accumulation of expressed protein as a function of time may be visually ascertained by the fact that the cells take on a bright red color during the course of induction. In all the cases tested so far, the fusion protein accumulates in the soluble fraction to high levels. A novel purification protocol has been designed to purify the fusion proteins using metal affinity chromatography, without the need of a hexahistidine-tag. Mass spectral analysis has shown that the fusion proteins are of full length. CD studies have shown that the solubilized fusion proteins are structured. The proteins of interest may be cleaved from the parent protein by either chemical or enzymatic means. The results presented here demonstrate the versatility of the cytochrome b5 based fusion system for the production of peptides and small proteins (<15 kDa).
Collapse
Affiliation(s)
- Ashima Mitra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | | | | | | | | | | |
Collapse
|
47
|
Abstract
Primary intraosseous carcinoma/odontogenic carcinomas are extremely rare malignant odontogenic tumours that are thought to arise from residues of odontogenic epithelium. An unusual case of primary intraosseous carcinoma arising de novo in a previously unreported site of posterior maxilla is described. The tumour was characterized by sheets of pleomorphic round-to-ovoid cells and marked osteoid/dentinoid formation with foci of globular mineralization.
Collapse
Affiliation(s)
- A Punnya
- Department of Oral Pathology and Microbiology, S.D.M College of Dental Sciences, Dharwad 580009, Karnataka, India
| | | | | | | |
Collapse
|
48
|
Kamat SS, Kumar GS, Raghunath V, Rekha KP. Permanent maxillary central incisor impaction: report of two cases. Quintessence Int 2003; 34:50-2. [PMID: 12674359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Impaction of the permanent maxillary central incisor is rare. Trauma to the primary maxillary anterior teeth is the most common cause. Two case reports of impacted permanent maxillary central incisors with a history of trauma to the primary maxillary anterior teeth are presented. In one case there was radiographic evidence of complete arrest of root formation, and in the other case the root was dilacerated from the cervical third and the enamel surface was rough.
Collapse
Affiliation(s)
- Sushant S Kamat
- Department of Oral Pathology, Shri Dharmasthala Manjunatheswara College of Dental Sciences and Hospital, Dharwad, Karnataka, India
| | | | | | | |
Collapse
|
49
|
|
50
|
Abstract
Eye lens alpha-crystallin is a member of the small heat shock protein (sHSP) family and forms large multimeric structures. Earlier studies have shown that it can act like a molecular chaperone and form a stable complex with partially unfolded proteins. We have observed that prior binding of the hydrophobic protein melittin to alpha-crystallin diminishes its chaperone-like activity toward denaturing alcohol dehydrogenase, suggesting the presence of mutually exclusive sites for these proteins in alpha-crystallin. To investigate the mechanism of the interaction between alpha-crystallin and substrate proteins, we determined the melittin-binding sites in alpha-crystallin by cross-linking studies. Localization of melittin-binding sites in alpha-crystallin resulted in the identification of RTLGPFYPSR and FVIFLDVKHFSPEDLTVK of alphaA-crystallin and FSVNLDVK of alphaB-crystallin as the chaperone sites. Of these sites, FVIFLDVKHFSPEDLTVK and FSVNLDVK were identified earlier as 1,1'-bi(4-anilino) naphthalene-5,5'-disulfonic acid (bis-ANS)-binding hydrophobic sites. Here we also report the synthesis and characterization of the peptide, KFVIFLDVKHFSPEDLTVK, having the melittin as well as bis-ANS-binding sequence of alphaA-crystallin. We show that this peptide has characteristics similar to that of alphaA-crystallin by in vitro thermal aggregation assay, gel filtration study, CD spectroscopy, and bis-ANS interaction studies. The peptide sequence corresponds to the beta3 and beta4 region present in the alpha-crystallin domain of sHSP 16.5. We hypothesize that the alpha-crystallin domain in other sHSPs may have a similar function and would likely possess the anti-aggregation property even when separated from the native protein.
Collapse
Affiliation(s)
- K K Sharma
- Mason Eye Institute, Department of Ophthalmology, University of Missouri, Columbia, Missouri, 65212, USA.
| | | | | | | |
Collapse
|