Browsing by Author "Petr Heneberg"

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Identification of a novel stress regulated FERM domain containing cytosolic protein having PTP activity in Setaria cervi, a bovine filarial parasite
(Academic Press Inc., 2015) Neetu Singh; Petr Heneberg; Nidhi Singh; Shio Kumar Singh; Sushma Rathaur
A 67 kDa cytosolic FERM domain containing protein having significant protein tyrosine phosphatases activity (PTPL) has been purified to homogeneity from Setaria cervi, a bovine filarial parasite. The MALDI-MS/MS analysis of the purified protein revealed 16 peptide peaks showing nearest match to Brugia malayi Moesin/ezrin/radixin homolog 1 protein and one peptide showing significant similarity with a region lying in the catalytic domain of human PTPD1. PTPL showed significant cross reactivity with the human PTP1B antibody and colocalize with actin in the coelomyrian cells of hypodermis in the parasite. PTPL was stress regulated as it showed marked decrease in the expression when exposed to Aspirin, an antifilarial drug and Phenylarsine Oxide, PTP inhibitor. © 2015 Elsevier Inc. All rights reserved.
Presence of ecto-protein tyrosine phosphatase activity is vital for survival of Setaria cervi, a bovine filarial parasite
(Springer Verlag, 2014) Neetu Singh; Petr Heneberg; Sushma Rathaur
The ecto protein tyrosine phosphatases (PTP) are known to play a crucial role in the pathogenesis and survival of the intracellular parasites. However, their presence and role in filarial parasites is still unknown. We found a significant amount of tyrosine phosphatase activity in the surface antigen fraction extracted from Setaria cervi (S. cervi), a bovine filarial parasite. An antibody designed against the conserved catalytic core of human protein tyrosine phosphatases, PTP1B cross reacted with a 63 kDa band in the surface antigen. We detected a significant amount of PTP activity in the intact S. cervi adult parasites as well as microfilariae in this study for the first time. This PTP may be localized on the surface of the parasite with an exposed active site available for the external substrates. The PTP activity was also inhibited by sodium orthovanadate and phenyl arsine oxide, specific inhibitors of PTP in both the life stages. The Km and Vmax for PTP in the adult parasites and microfilariae were determined to be 2.574 ± 0.14 mM; 206.3 ± 2.75 μM Pi/h/two parasites and 5.510 ± 0.59 mM; 62.27 ± 2.27 μM Pi/h/106parasites respectively using O-P-L-Tyrosine as substrate. Interestingly, a positive correlation was observed between the inhibition in PTP activity and reduction in the motility/ viability of the parasites when they were subjected to the specific PTP inhibitors (Orthovanadate and Phenyl arsine oxide) for 4 h in the KRB maintenance medium. The activity was also significantly inhibited in the parasites exposed to antifilarial drug/compounds for e.g. Diethylcarbamazine, Acetylsalicylic Acid and SK7, a methyl chalcone. Therefore suggesting a possible role played by PTP in the survival of the parasite, its interaction with the host as well as in the screening of newly synthesized antifilarials/drugs. © 2014, Springer-Verlag Berlin Heidelberg.