Cell migration requires the dynamics of the actin-microtubule cytoskeleton and the regulation of both cell- matrix and cell-cell adhesion;however, there is a fundamental gap in our knowledge of how these networks are coordinated. This gap prevents a comprehensive understanding of the mechanisms that govern cell movements, including metastasis. The long term goal of this project is to determine how adhesion and the cytoskeleton are integrated during cell migration, focusing on how the Drosophila spectraplakin Short-stop and its mammalian counter-part MACF1/ACF7, model cytolinkers and integrators, coordinate these networks. Spectraplakins are excellent candidates for this coordination as they can physically cross-link actin and microtubules while playing a critical roles in the regulation o adhesion. Cell migration is a result of a synergistic relationship between these networks;therefore investigating molecules that potentially facilitate this cooperative interaction represens the next crucial step in understanding this process. Our central hypothesis is that molecules that coordinate actin-microtubule cross-linking and adhesion function as a nexus in the regulation of cell migration. This hypothesis has been formulated on the basis of data generated in the applicant's laboratory as well as mounting evidence present in the literature. The rationale for the proposed research is that metastasis represents a major cause of mortality in cancer patients. A more extensive understanding of cell migration will lead to the identification of futur therapeutic targets and ultimately a decrease in cancer related deaths. This hypothesis will be tested by two specific aims: 1) Determine how the spectraplakins Shot and MACF1 regulate cell migration;and 2) Determine the biological mechanisms that regulate their activity. To accomplish the first aim I will use a combination novel motile Drosophila cell lines and mammalian tissue culture cells with high resolution microscopy. To complement these studies analysis of Shot's role in cell migration will be carried out in an in vivo model of cell migration border cell migration. In the second aim biochemical and microscopic analysis will be used to determine whether Shot and MACF1 undergo an intramolecular conformational change. For this aim both cell biology based and developmental biology based assays will be used to determine the biological significance of this conformational change. The approach is innovative because it will utilize both cell culture models,Drosophila and mammalian, and an in vivo model of cell migration in a complementary manner. The proposed research is significant as its aim is to elucidate the combinatorial affects of adhesion and cytoskeletal dynamics during cell migration. This knowledge has the potential to advance the field of cell motility, and putatively uncover therapeutic targets for the prevention of metastasis.
Cell motility, which is the basis of metastasis, requires the integration of the actin and microtubule cytoskeletons as well as the adhesion machinery. Key molecules facilitate this coordination is vital to our comprehensive understanding of cell migration. The spectraplakin family of proteins are unique in that they physically couple actin and microtubules, and regulate both cell-cell and cell-matrix adhesion.
|Applewhite, Derek A; Grode, Kyle D; Duncan, Mara C et al. (2013) The actin-microtubule cross-linking activity of Drosophila Short stop is regulated by intramolecular inhibition. Mol Biol Cell 24:2885-93|