@article {516, title = {A new C-type lectin (RVsnaclec) purified from venom of Daboia russelii russelii shows anticoagulant activity via inhibition of FXa and concentration-dependent differential response to platelets in a Ca{\texttwosuperior}$^{+}$-independent manner. (Mass spectrometry)}, journal = {Thromb Res}, volume = {134}, year = {2014}, month = {2014 Nov}, pages = {1150-6}, abstract = {

This is the first report on the characterization of a snaclec (RVsnaclec) purified from Daboia russelii russelii venom. The RVsnaclec is a heterodimer of two subunits, α (15.1 kDa) and β (9 kDa). These subunits are covalently linked to form multimeric (αβ)$_{2}$ and (αβ)$_{4}$ structures. Peptide mass fingerprinting analysis of RVsnaclec via LC-MS/MS demonstrated its similarity to snaclecs purified from other viperid snake venoms. Two tryptic peptide sequences of RVsnaclec revealed the putative conserved domains of C-type lectin (CTL). RVsnaclec dose-dependently increased the Ca-clotting time and prothrombin time of platelet-poor plasma (PPP); however, it did not affect the partial thromboplastin time (APTT) or thrombin time of PPP. The in vitro and in vivo anticoagulant activity of RVsnaclec is correlated to its binding and subsequent uncompetitive inhibition of FXa (Ki = 0.52 μmole) in a Ca(2+)-independent manner; however, supplementation with 0.25 mM Ca(2+) enhanced the Xa binding potency of RVsnaclec. Monovalent or polyvalent antivenom failed to neutralize its anticoagulant potency, and RVsnaclec did not inhibit trypsin, chymotrypsin, thrombin or plasmin. RVsnaclec was devoid of hemolytic activity or cytotoxicity against several human cancer cell lines, demonstrated concentration-dependent aggregation and deaggregation of human platelets, and inhibited the ADP-induced aggregation of platelet. RVsnaclec (5.0 mg/kg body weight) was non-lethal to mice and showed no adverse pharmacological effects, suggesting that it has potential as a lead compound for future therapeutic applications in cardiovascular disorders.

}, keywords = {Animals, Anticoagulants, Blood Coagulation, Blood Platelets, Calcium, Factor Xa, Factor Xa Inhibitors, Goats, Humans, Lectins, C-Type, Mice, Platelet Aggregation, Russell{\textquoteright}s Viper, Viper Venoms}, issn = {1879-2472}, doi = {10.1016/j.thromres.2014.09.009}, author = {Mukherjee, Ashis K and Dutta, Sumita and Mackessy, Stephen P} } @article {478, title = {Functional implementation of Drosophila itpr mutants by rat Itpr1. [Drosophila facility]}, journal = {J Neurogenet}, volume = {26}, year = {2012}, month = {2012 Sep}, pages = {328-37}, abstract = {

The Drosophila inositol 1,4,5-trisphosphate receptor (IP(3)R) and mammalian type-1 IP(3)Rs have 57-60\% sequence similarity and share major domain homology with each other. Mutants in the single Drosophila IP(3)R gene, itpr, and Itpr1 knockout mice both exhibit lethality and defects in motor coordination. Here the authors show that the rat type-1 IP(3)R, which is the major neuronal isoform, when expressed in the pan-neuronal domain in Drosophila, functionally complements Drosophila IP(3)R function at cellular and systemic levels. It rescues the established neuronal phenotypes of itpr mutants in Drosophila, including wing posture, flight, electrophysiological correlates of flight maintenance, and intracellular calcium dynamics. This is the first in vivo demonstration of functional homology between a mammalian and fly IP(3)R. This study also paves the way for cellular and molecular analyses of the spinocerebellar ataxias in Drosophila, since SCA15/16 is known to be caused by heterozygosity of human ITPR1.

}, keywords = {Animals, Animals, Genetically Modified, Calcium, Cells, Cultured, Cytosol, Drosophila, Drosophila Proteins, Flight, Animal, Gene Expression Regulation, Genetic Therapy, Inositol 1,4,5-Trisphosphate Receptors, Larva, Movement Disorders, Mutation, Neurons, Physical Stimulation, Rats, Transcription Factors, Wings, Animal}, issn = {1563-5260}, doi = {10.3109/01677063.2012.697501}, author = {Chakraborty, Sumita and Hasan, Gaiti} } @article {483, title = {Inositol 1,4,5-trisphosphate receptor and dSTIM function in Drosophila insulin-producing neurons regulates systemic intracellular calcium homeostasis and flight. [Drosophila facility]}, journal = {J Neurosci}, volume = {30}, year = {2010}, month = {2010 Jan 27}, pages = {1301-13}, abstract = {

Calcium (Ca(2+)) signaling is known to regulate the development, maintenance and modulation of activity in neuronal circuits that underlie organismal behavior. In Drosophila, intracellular Ca(2+) signaling by the inositol 1,4,5-trisphosphate receptor and the store-operated channel (dOrai) regulates the formation and function of neuronal circuits that control flight. Here, we show that restoring InsP(3)R activity in insulin-producing neurons of flightless InsP(3)R mutants (itpr) during pupal development can rescue systemic flight ability. Expression of the store operated Ca(2+) entry (SOCE) regulator dSTIM in insulin-producing neurons also suppresses compromised flight ability of InsP(3)R mutants suggesting that SOCE can compensate for impaired InsP(3)R function. Despite restricted expression of wild-type InsP(3)R and dSTIM in insulin-producing neurons, a global restoration of SOCE and store Ca(2+) is observed in primary neuronal cultures from the itpr mutant. These results suggest that restoring InsP(3)R-mediated Ca(2+) release and SOCE in a limited subset of neuromodulatory cells can influence systemic behaviors such as flight by regulating intracellular Ca(2+) homeostasis in a large population of neurons through a non-cell-autonomous mechanism.

}, keywords = {Animals, Calcium, Calcium Signaling, Cell Membrane, Cells, Cultured, Central Nervous System, Drosophila, Drosophila Proteins, Flight, Animal, Homeostasis, Inositol 1,4,5-Trisphosphate Receptors, Insulin, Intracellular Fluid, Membrane Proteins, Mutation, Neural Pathways, Neurons, Pupa, Stromal Interaction Molecule 1}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.3668-09.2010}, author = {Agrawal, Neha and Venkiteswaran, Gayatri and Sadaf, Sufia and Padmanabhan, Nisha and Banerjee, Santanu and Hasan, Gaiti} }