Functional Characterisation and Drug Target Validation of a Mitotic Kinesin-13 in Trypanosoma brucei

Mitotic kinesins are essential for faithful chromosome segregation and cell proliferation. Therefore, in humans, kinesin motor proteins have been identified as anti-cancer drug targets and small molecule inhibitors are now tested in clinical studies. Phylogenetic analyses have assigned five of the approximately fifty kinesin motor proteins coded by Trypanosoma brucei genome to the Kinesin-13 family. Kinesins of this family have unusual biochemical properties because they do not transport cargo along microtubules but are able to depolymerise microtubules at their ends, therefore contributing to the regulation of microtubule length. In other eukaryotic genomes sequenced to date, only between one and three Kinesin-13s are present. We have used immunolocalisation, RNAi-mediated protein depletion, biochemical in vitro assays and a mouse model of infection to study the single mitotic Kinesin-13 in T. brucei. Subcellular localisation of all five T. brucei Kinesin-13s revealed distinct distributions, indicating that the expansion of this kinesin family in kinetoplastids is accompanied by functional diversification. Only a single kinesin (TbKif13-1) has a nuclear localisation. Using active, recombinant TbKif13-1 in in vitro assays we experimentally confirm the depolymerising properties of this kinesin. We analyse the biological function of TbKif13-1 by RNAi-mediated protein depletion and show its central role in regulating spindle assembly during mitosis. Absence of the protein leads to abnormally long and bent mitotic spindles, causing chromosome mis-segregation and cell death. RNAi-depletion in a mouse model of infection completely prevents infection with the parasite. Given its essential role in mitosis, proliferation and survival of the parasite and the availability of a simple in vitro activity assay, TbKif13-1 has been identified as an excellent potential drug target

India: A Contradictory Record

This chapter provides a review of the role of women in Indian politics, with a focus on female legislators. It begins with an account of the entry of women into politics in the early 20th century. Second, it looks at the gradual increase in the number of women MPs and the barriers they have faced. The third section presents the debate that resulted in quotas (‘reservations’) for women in local-level politics, but not in the more influential parliament and state assemblies. The final section is about some characteristics of women MPs. This review demonstrates some of the key barriers that keep women out of elected office in India, but also highlights the diversity of the women who have come to power despite these obstacles

Elastic protein-based polymers a step towards plasticity: Thermal stability of glu-containing co-polypeptides as analyzed by differential scanning calorimetry

Plastic protein-based polymers with the same conformational potential, but with different degree of thermal stability have been synthesized and thermally characterized by differential scanning calorimetry to provide the conception of behavior of thermoplasticity. Dramatic increase in the temperature between melting and decomposition transitions has been observed, upon inclusion of glutamic acid residue into the hydrophobic sequence of FVGVP. Glu-containing co-polymers of IVGVP showed a markedly different behavior by exhibiting exothermic crystallization transition before melting shows the typical thermoplasticity. Secondary structure in trifluoroethanol for all the polymers show, a well behaved α-helix as evident from the circular dichroism studies, in association with a significant amount of random structure contributes to extended stability