Dr. Shatarupa Sinha's Talk

Aug 31, 2018 - 10:00

Aug 31, 2018 - 11:00

Room No. 240 first floor next to Chem. Engg. deptl. office

Seminars

Shatarupa Sinha is currently a visiting faculty at the Centre of Excellence in Basic Sciences (CEBS) University of Mumbai

Dynamics in Human Breast Cells Protein kinase C (PKC) engenders motility through phosphorylation of alpha-tubulin at Ser-165 in non-transformed MCF-10A cells. This talk will report on the use of live-cell imaging to explore the impact of PKC-mediated phosphorylation on microtubule (MT) dynamics. MTs fluorescently labeled with GFP-alpha-tubulin were treated with diacylglycerol (DAG)-lactone (a membrane-permeable PKC activator) or co-transfected with a pseudophosphorylated S165D-alpha-6-tubulin mutant.Each condition increased the dynamicity of MTs by stimulating the rate and duration of the growth phase and decreasing the frequency of catastrophe events. In MDA-MB-231 metastatic breast cells where the intrinsic PKC activity is high these MT growth parameters were also high but could be suppressed by expression of phosphorylation-resistant S165N-a;pha-6-tubulin or by treatment with a pan-PKC inhibitor (bis-indoleylmaleimide). Subcellular fractionation of MCF-10A cells showed that phosphorylation (via DAG-lactone) or pseudophosphorylation of alpha-6-tubulin increased its partitioning into MTs as compared to controls and produced longer more stable MTs. Following expression of the plus-end binding protein GFP-EB1 DAG-lactone accelerated the formation and increased the number of nascent MTs. Expression of S165D-alpha-6-tubulin promoted Rac1 activation and Rac1-dependent cell motility. To further validate these findings in an in-vivo simulated environment a 3D-Matrigel assay was conducted in the aforementioned conditions; the difference brought out by site-specific phosphorylation of alpha--tubulin is evident from the figures excerpted below. Altogether these findings call attention to PKC-mediated phosphorylation of alpha-tubulin as a novel mechanism for controlling the dynamics of MTs that result in enhance cell migration.About the speaker: Shatarupa Sinha is currently a visiting faculty at the Centre of Excellence in Basic Sciences (CEBS) University of Mumbai where she has been teaching for the past four years. Since last year she is also associated with Prof. Abhijit Majumder’s lab in the Chemical Engineering department of IIT Bombay studying the effect of substrate stiffness on stem cell properties. She earned her PhD from the City University of New York in 2014. For her PhD thesis she established the role of protein kinase and -tubulin in the migration of breast epithelial and cancer cells. Apart from this work she collaborated with chemists in analysing the biological efficacy of small-molecule inhibitors.