Abstract:
This thesis describes the functional analysis of the cytoskeletal protein Rudhira in cell
migration. Rudhira is predominantly expressed in the embryonic vasculature and adult
neo-angiogenic processes such as wound healing and pathological processes such as tumor
progression. Rudhira is a cytoskeletal protein that plays a key role in directional cell
migration, by facilitating actin cytoskeleton reorganization and focal adhesion turnover.
Several in vivo and in vitro model systems such as the fruit fly, mouse, zebrafish and
endothelial cell lines are used for characterization of the fine-tuned and complex regulatory
networks that regulate blood vessel formation. Two such model systems that are used in
our laboratory to study the functions of Rudhira are rudhira knockout mice and rudhira
knockdown endothelial cell lines. I have generated a rudhira knockout endothelial cell line,
which could serve as a resource and also overcome some of the limitations of the previous
models. The inherent difference in the predicted domain architecture of the two halves of
Rudhira suggests differences in their molecular functions primarily with respect to cell
migration. Thus, using techniques like in vitro wound healing assay and immunostaining, I
have attributed some of the cell migration steps regulated by Rudhira, including,
microtubule stabilization and stress fiber reduction, to the two halves of the protein. Taken
together, this study offers fresh insights into the mechanism of regulation of cell migration
by Rudhira and may be applicable to better understanding the role of cell migration in
blood vessel formation. Development of the cardiovascular system requires the formation of blood vessels, which occurs
by two main processes: vasculogenesis and angiogenesis. Blood vessel formation occurs during
embryogenesis as well as in adults, both in physiological conditions like wound healing and
menstrual cycle and pathological conditions such as ischemia, retinopathies and tumors.
Dysregulation of such a critical process is often associated with vascular diseases or metastatic
tumors. The cellular and molecular mechanisms of physiological and pathological angiogenesis
are quite similar. Hence, molecules which are expressed in both contexts are of great significance
since they would not only provide a better understanding of vascular development, but may
prove to be potential therapeutic targets.