anuraag shrivastav - Academia.edu (original) (raw)

Papers by anuraag shrivastav

Journal of Biological …, 2005

N-Myristoyltransferase (NMT) transfers myristate to an amino-terminal glycine of many eukaryotic ... more N-Myristoyltransferase (NMT) transfers myristate to an amino-terminal glycine of many eukaryotic proteins. In yeast, worms, and flies, this enzyme is essential for viability of the organism. Humans and mice possess two distinct but structurally similar enzymes, NMT1 and NMT2. These ...

International Journal of Molecular Sciences

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is an essential protein that regulat... more Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is an essential protein that regulates cellular processes such as cell proliferation, apoptosis, and differentiation. It is known to bind with several proteins to carry out various cellular functions. In this study, we report for the first time that IGFBP-3 is a histone 3 (H3) binding protein. Sub-cellular fractionation was performed to separate into cytosolic fraction, nucleic acid binding protein fraction and insoluble nuclear fraction. Using ligand blot analysis, we identified a ~15 kDa protein that can interact with IGFBP-3 in the insoluble nuclear fraction. The 15 kDa protein was confirmed as histone 3 by far-Western blot analysis and co-immunoprecipitation experiments. A dot-blot experiment further validated the binding of IGFBP-3 with H3. The intensity of IGFBP-3 on dot-blot showed a proportional increase with H3 concentrations between 2.33 pmol–37.42 pmol. Our results support the presence of protein-protein interac...

Frontiers in Cell and Developmental Biology

Physiological and Biochemical Zoology

Scientific reports, Jan 28, 2018

Breast cancer is the most common cancer in women worldwide. Hormone receptor breast cancers are t... more Breast cancer is the most common cancer in women worldwide. Hormone receptor breast cancers are the most common ones and, about 2 out of every 3 cases of breast cancer are estrogen receptor (ER) positive. Selective ER modulators, such as tamoxifen, are the first line of endocrine treatment of breast cancer. Despite the expression of hormone receptors some patients develop tamoxifen resistance and 50% present de novo tamoxifen resistance. Recently, we have demonstrated that activated mammalian target of rapamycin (mTOR) is positively associated with overall survival and recurrence free survival in ER positive breast cancer patients who were later treated with tamoxifen. Since altered expression of protein kinase B (PKB)/Akt in breast cancer cells affect N-myristoyltransferase 1 (NMT1) expression and activity, we investigated whether mTOR, a downstream target of PKB/Akt, regulates NMT1 in ER positive breast cancer cells (MCF7 cells). We inhibited mTOR by treating MCF7 cells with rapam...

Frontiers in immunology, 2017

Protein N-myristoylation is a cotranslational lipidic modification specific to the alpha-amino gr... more Protein N-myristoylation is a cotranslational lipidic modification specific to the alpha-amino group of an N-terminal glycine residue of many eukaryotic and viral proteins. The ubiquitous eukaryotic enzyme, N-myristoyltransferase, catalyzes the myristoylation process. Precisely, attachment of a myristoyl group increases specific protein-protein interactions leading to subcellular localization of myristoylated proteins with its signaling partners. The birth of the field of myristoylation, a little over three decades ago, has led to the understanding of the significance of protein myristoylation in regulating cellular signaling pathways in several biological processes especially in carcinogenesis and more recently immune function. This review discusses myristoylation as a prerequisite step in initiating many immune cell signaling cascades. In particular, we discuss the hitherto unappreciated implication of myristoylation during myelopoiesis, innate immune response, lymphopoiesis for T...

Molecular medicine reports

This study aimed to elucidate the mode of action of curcumin (CCM) as an anticancer agent, and to... more This study aimed to elucidate the mode of action of curcumin (CCM) as an anticancer agent, and to investigate its effects on the proliferation and induction of apoptosis in HT29 human colon cancer cells. We examined the effect of CCM on two cysteine protease families, namely caspases and calpains, which are known to induce apoptosis in a number of cancer cells. We demonstrated that CCM reduces cell proliferation in HT29 cells with an IC50 value of 50±0.015 µM. Western blot analysis indicated that CCM induced apoptosis in HT29 cells by activating the expression of caspases-3 and -12, but not caspase-9. CCM also induced apoptosis in these cells through the involvement of calpain. These findings indicate that CCM-induced apoptosis in HT29 cells follows the caspase-12 apoptotic pathway, and also involves calpain.

Cancer research, Jan 15, 2003

N-myristoyltransferase (NMT) is an essential eukaryotic enzyme that catalyzes the cotranslational... more N-myristoyltransferase (NMT) is an essential eukaryotic enzyme that catalyzes the cotranslational and/or posttranslational transfer of myristate to the NH(2) terminus of the glycine residue of a number of important proteins that have diverse biological functions and thus have been proposed as potential targets for chemotherapeutic drug design. Earlier, we demonstrated that NMT is more active in colonic epithelial neoplasms than in corresponding normal-appearing colonic tissue. Furthermore, an increased expression of NMT was also observed in gallbladder carcinoma. In the present study, we report a novel protein inhibitor of NMT. This protein caused a potent concentration-dependent inhibition of human NMT with half-maximal inhibition at 4.5 +/- 0.35 nM. This study will serve as a template for further investigations in the area of protein myristoylation.

Breast Cancer Research, 2014

Introduction: A phosphorylation score for estrogen receptor-alpha (ERα), called P7 score, was sho... more Introduction: A phosphorylation score for estrogen receptor-alpha (ERα), called P7 score, was shown previously to be an independent prognostic factor in breast cancer patients treated with tamoxifen. Since mechanistic target of rapamycin (mTOR) activation is implicated in resistance to endocrine therapy in breast cancer we determined whether mechanistic target of rapamycin complex 1 (mTORC1) activation, measured by phosphorylation on S2448 (p-mTOR), was associated with the P7-score and/or clinical outcome in the same cohort. Methods: mTOR phosphorylation status was determined at S2448 residue in vivo by immunohistochemistry in a cohort of more than 400 well-characterized ERα positive breast tumors. MCF7 cells were treated with estrogen and activation of mTOR pathway was determined by Western blotting. Results: Contrary to earlier reports, p-mTOR expression, measured by immunohistochemistry, was negatively associated with size and nodal status. Additionally, p-S2448 mTOR expression was positively correlated with p-S118-ERα, p-S167-ERα and p-S282-ERα but negatively correlated with p-T311-ERα. Consistent with these, p-S2448 mTOR was negatively associated with P7-score and was significantly associated with overall survival (OS) (hazard ratio (HR) = 0.61, P = 0.028, 95% confidence interval (CI) 0.39 to 0.95, n = 337) and relapse-free survival (HR = 0.58, P = 0.0032, 95% CI 0.41 to 0.83, n = 337) following univariate but not multivariate analysis. Furthermore, we show that estrogen can regulate phosphorylation of mTOR and its down stream target p70S6 kinase. Additionally, recombinant mTOR can phosphorylate ERα in vitro. Conclusions: These data suggest that in breast tumors where there is intact estrogen regulated signaling, mTOR is regulated by estrogen and therefore associated with an increased likelihood of responsiveness to endocrine therapy.

International Journal of Molecular Medicine, 2006

The response of living cells to change in cell environment depends on the action of second messen... more The response of living cells to change in cell environment depends on the action of second messenger molecules. The two second messenger molecules cAMP and Ca 2+ regulate a large number of eukaryotic cellular events. Calmodulin-stimulated cyclic nucleotide phosphodiesterase (PDE1) is one of the key enzymes involved in the complex interaction between cAMP and Ca 2+ second messenger systems. Some PDE1 isozymes have similar kinetic and immunological properties but are differentially regulated by Ca 2+ and calmodulin. Accumulating evidence suggests that the activity of PDE1 is selectively regulated by cross-talk between Ca 2+ and cAMP signalling pathways. These isozymes are also further distinguished by various pharmacological agents. We have demonstrated a potentially novel regulation of PDE1 by calpain. This study suggests that limited proteolysis by calpain could be an alternative mechanism for the activation of PDE1. We have also shown PDE1 activity, expression and effect of calpain in the rat model in vitro of cardiac ischemiareperfusion. Contents 1. Introducton 2. Kinetic properties of various PDE1 isozymes 3. Differential regulation of PDE1 by CaM and Ca 2+ 4. Coupling between Ca 2+ and cAMP second messengers in the regulation of PDE1 5. Role of autophosphorylation of PDE1B1 by CaMdependent protein kinase II 6. Differential inhibition of PDE1 isozymes and its therapeutic applications 7. Role of proteolysis in regulating PDE1A2 8. Role of PDE1A1 in ischemic-reperfused heart 9. Conclusion

Breast Cancer Management, 2012

SUMMARY Endocrine therapies are used to treat estrogen receptor-positive (ER+) breast cancer; how... more SUMMARY Endocrine therapies are used to treat estrogen receptor-positive (ER+) breast cancer; however, patients develop resistance in some cases due to hormone-independent activation of ER signaling. Dysregulation of mTOR, a central hub for various signaling pathways regulated by hormones and growth factors, is a mechanism of endocrine therapy resistance. Activation of kinases in these pathways can cause ligand-independent ER signaling. Phosphorylation of ER regulates activity and predicts clinical outcome in ER+ breast cancer. PI3K/Akt/mTOR pathway activation in breast cancer is common and considered a therapeutic target. PI3K/Akt/mTOR signaling is complex and interacts with ER signaling. mTOR’s downstream target p70S6K negatively regulates Akt on one hand and can phosphorylate ER. Moreover, overexpressed p70S6K activates ER in breast cancer cells. An overall understanding of signaling events, especially those governed by mTOR, is important in deciding treatment protocols for ER+ b...

International Journal of Angiology, 2009

AfCS-Nature Molecule Pages, 2009

Veterinary Research, 2010

N-myristoyltransferase (NMT) attaches a 14 carbon fatty acid, myristic acid, to the N-terminal gl... more N-myristoyltransferase (NMT) attaches a 14 carbon fatty acid, myristic acid, to the N-terminal glycine residue of proteins. NMT exists in two isoforms NMT1 and NMT2. Myristoylated proteins play critical roles in protein-protein interactions, cell signaling and oncogenesis. Although elevated expression of NMT1 has been described in colorectal carcinoma, its expression and roles in normal and inflamed lungs of the cattle are unknown. Therefore, we investigated the expression and activity of NMT in a bovine model of lung inflammation induced with Mannheimia hemolytica and in vitro in neutrophils and macrophages. Western blots revealed increased expression of NMT1 in lungs from infected animals compared to control animals. Total NMT activity was reduced in inflamed lungs compared to control animals (p < 0.05) along with increased expression of enolase, a putative inhibitor of NMT. NMT1 staining was observed in the septum, vascular endothelium and the epithelium in the lungs from control as well as infected calves. NMT1 expression was intense in neutrophils in the necrotic areas in the inflamed lungs. Immuno-electron microscopy localized NMT1 in cytoplasm and nuclei of endothelium, pulmonary intravascular macrophages and airway epithelium. Total NMT activity and NMT1 expression were increased in neutrophils and macrophages exposed to Escherichia coli LPS in vitro. NMT knockdown increased apoptosis in activated neutrophils. This is the first report demonstrating expression of NMT in normal and inflamed lungs and a novel role for NMT in regulation of neutrophil lifespan.

Oncology Reports, 2007

N-myristoyltransferase (NMT) catalyzes the myristoylation of proteins involved in signal transduc... more N-myristoyltransferase (NMT) catalyzes the myristoylation of proteins involved in signal transduction, cellular transformation, differentiation, proliferation and oncogenesis. In this study, we report for the first time on the elevated NMT activity in oral squamous cell carcinoma (OSCC). Increased activity is marked with increased staining for NMT in the OSCC samples compared to the normal adjacent tissues. In addition, we observed increased staining for the N-myristoyltransferase inhibitor protein 71 (NIP71) in the OSCC samples compared to the control tissues. These findings suggest the regulatory relationship between NMT and NIP71 during tumorigenesis. It is possible that the increased activity results in the overexpression of NIP71 in an effort to control NMT activity.

Neurochemical Research, 2005

N-myristoylation is a process of covalent irreversible protein modification that promotes associa... more N-myristoylation is a process of covalent irreversible protein modification that promotes association of proteins with membranes. Based on our previous findings of elevated N-myristoyltransferase (NMT) activity in colonic epithelial neoplasms that appears at an early stage in colonic carcinogenesis, together with elevated NMT expression in human colorectal and gallbladder carcinomas, we investigated NMT activity and protein expression of NMT1 and NMT2 in human brain tumors and documented elevated NMT activity and higher protein expressions. For the first time, we have demonstrated that NMT has the potential to be used as a marker of human brain tumors. However, further studies with larger number of patients are required to establish its role as a complementary diagnostic tool. This finding has significant implications for further understanding of biological mechanisms involved in tumorigenesis, as well as for diagnosis and therapy of human brain tumors.