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SCIS organises a seminar by Dr. Sabeeha Hasnain

SCIS organises a seminar by Dr. Sabeeha Hasnain

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SCIS organises a seminar by Dr. Sabeeha Hasnain
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JAWAHARLAL NEHRU UNIVERSITY

SCHOOL OF COMPUTATIONAL AND INTEGRATIVE SCIENCES

S E M I N A R

 

Speaker: Dr. Sabeeha Hasnain
Title: Crowding modulates the stepping dynamics of Kinesin
Date     22-06-2018
Time   3.30pm
Venue   Seminar room, SCIS, JNU

Abstract

Kinesins are dimeric motor proteins which move along the Microtubule (MT) and transport cargo like cellular organelles, mRNA and signaling molecules towards the cell periphery. Macromolecular crowding inside the cell is likely to play a key role in modulating the stepping dynamics of kinesin owing to volume exclusion effects. We will present Brownian dynamics simulation results, using the Self-Organized Polymer model of the Kinesin-Microtubule complex developed by Zhang and Thirumalai [1] in the presence of spherical crowders. We find that the docking of the neck-linker, a key event in driving the stepping process, is unaffected by the crowding agents. In contrast, the diffusive motion of the trailing head (TH), which covers the majority of the 16 nm step [2], is greatly impeded due to crowding. Moreover, crowders decrease the lateral displacement of the trailing head (TH), thus confining stepping the TH diffusion to the central protofilament of the microtubule (MT). The effect is most apparent at a high concentration of crowders, when excluded volume effects hinder the motion of TH. This results in a reduced distance between the free and bound kinesin head, resulting in a stochastic motion of the TH along the MT. We relate our findings to the experiments of Conway and Ross [3], which showed ​ in-vitro ​ the reversal of kinesin motion in a crowded environment.

References:

[1] Zhang Z, Thirumalai D (2012) Dissecting the kinematics of the kinesin step. ​ Structure 20:628-640.

[2] Zhang Z, Goltzvik Y, Thirumalai D (2017) Parsing the roles of neck-linker docking and tethered head diffusion in the stepping dynamics of kinesin. ​ Proc. Natl. Acad. Sci USA. E9838-E9845.

[3] Conway L, Ross J L (2014) Kinesin Motor Transport is Altered by Macromolecular Crowding and Transiently Associated Microtubule-Associated Proteins. ​ arXiv ​ :1409.3455.

A warm welcome to the modified and updated website of the Centre for East Asian Studies. The East Asian region has been at the forefront of several path-breaking changes since 1970s beginning with the redefining the development architecture with its State-led development model besides emerging as a major region in the global politics and a key hub of the sophisticated technologies. The Centre is one of the thirteen Centres of the School of International Studies, Jawaharlal Nehru University, New Delhi that provides a holistic understanding of the region.

Initially, established as a Centre for Chinese and Japanese Studies, it subsequently grew to include Korean Studies as well. At present there are eight faculty members in the Centre. Several distinguished faculty who have now retired include the late Prof. Gargi Dutt, Prof. P.A.N. Murthy, Prof. G.P. Deshpande, Dr. Nranarayan Das, Prof. R.R. Krishnan and Prof. K.V. Kesavan. Besides, Dr. Madhu Bhalla served at the Centre in Chinese Studies Programme during 1994-2006. In addition, Ms. Kamlesh Jain and Dr. M. M. Kunju served the Centre as the Documentation Officers in Chinese and Japanese Studies respectively.

The academic curriculum covers both modern and contemporary facets of East Asia as each scholar specializes in an area of his/her interest in the region. The integrated course involves two semesters of classes at the M. Phil programme and a dissertation for the M. Phil and a thesis for Ph. D programme respectively. The central objective is to impart an interdisciplinary knowledge and understanding of history, foreign policy, government and politics, society and culture and political economy of the respective areas. Students can explore new and emerging themes such as East Asian regionalism, the evolving East Asian Community, the rise of China, resurgence of Japan and the prospects for reunification of the Korean peninsula. Additionally, the Centre lays great emphasis on the building of language skills. The background of scholars includes mostly from the social science disciplines; History, Political Science, Economics, Sociology, International Relations and language.

Several students of the centre have been recipients of prestigious research fellowships awarded by Japan Foundation, Mombusho (Ministry of Education, Government of Japan), Saburo Okita Memorial Fellowship, Nippon Foundation, Korea Foundation, Nehru Memorial Fellowship, and Fellowship from the Chinese and Taiwanese Governments. Besides, students from Japan receive fellowship from the Indian Council of Cultural Relations.