A biophysical approach to understand the crosstalk between cytoplasmic streaming and the dynamics of the cytoskeleton (in the Drosophila oocyte)
| Dates: | 10 February 2015 |
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| Times: | 15:30 - 17:00 |
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| What is it: | Seminar |
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| Organiser: | Faculty of Life Sciences |
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| Who is it for: | University staff, Current University students |
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| Speaker: | Dr Isabel Palacios |
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Our main research aim is to investigate the creation of cellular asymmetries in the Drosophila oocyte, and its relation with the fluid mechanical properties of the cytoplasm. The major microtubule motor protein Kinesin is essential to localize key developmental molecules to precise regions of the oocyte. As these developmental determinants are being localized, microtubules and Kinesin also induce the vigorous movement of the oocyte cytoplasm, known as cytoplasmic streaming. Cytoplasmic streaming was discovered in 1774, but many fundamental questions have remained unanswered: How does the fluid motion arise? What is the relationship between the cellular asymmetries and the underlying forces of the observed flows?
Cytoplasmic streaming contributes to the asymmetric localization of molecules and structures, as well as the distribution of nutrients and organelles. Yet little is known quantitatively about the relationship between streaming and the motor activity which drives it. We have engaged in a comprehensive experimental and theoretical study of fluid dynamical and transport issues. We have recently used Particle Image Velocimetry to quantify the statistical properties of Kinesin-dependent streaming. We find that streaming can be used to detect subtle changes in Kinesin activity and that the flows reflect the architecture of the microtubule cytoskeleton. Furthermore, based on characterization of the rheology of the cytoplasm in vivo, we establish estimates of the number of Kinesins required to drive the observed streaming1.
Now, we are determining the different contributions of cytoplasmic streaming to cytoskeleton organization and cell polarity, as well as deciphering the mechanisms by which the actin and microtubule cytoskeletons regulate the different observed regimes of cytoplasmic streaming.
Our work on other functions of microtubule motor proteins both in the oocyte (mostly published) and in motor neurons (unpublished) will also be discussed.
Speaker
Dr Isabel Palacios
Organisation: University of Cambridge
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1.006
AV Hill Building
Manchester
