The long-term goal of this project is to understand how cells regulate cellular force production that drives cell migration and other contractile behaviors such as invasion and matrix remodeling. The current submissions focuses on a model of epithelial-to-mesenchymal transition (EMT), in which normal mouse mammary gland cells, which are epithelial in behavior, can be triggered to switch to a mesenchymal, more invasive state in response to the cytokine TGFb. We have recently discovered dramatic regulation of myosin II functions during EMT in this mammary gland model, including nonmuscle myosin II isoform switch, and an upregulation of MHC phosphorylation. Given earlier studies by our group and others documenting MHC phosphorylation as a critical regulator of myosin II filament assembly control during cell migration, our new studies support a model that myosin II isoform switches and MHC phosphorylation may be critical mediators of the enhanced invasive migration behavior and invasiveness that is a hallmark of the switch to the mesenchymal state. We propose a series of cell biological studies to establish the mechanical role of the induced myosin II isoform (myosin IIB), to establish the role of myosin II heavy chain phosphorylation that is induced during EMT, and to identify how cells that go through EMT upregulate myosin II heavy chain phosphorylation. At a broad level, these studies have relevance for understanding how cells upregulate their motility behavior during normal developmental events such as mesoderm initiation and neural tube formation. These studies also have strong relevance to understanding developmental decisions that occur during mammary ductal formation, where cells differentiate towards epithelial versus mesenchymal fates. Finally, these studies have very strong relevance to understanding how cellular contractile/motility machinery is upregulated in pathological settings such as tumor progression to metastatic states and tissue fibrosis.
This project focuses on a fundamental developmental switch, where cells in an epithelial surface sheet detach from each other and become migratory. This process occurs in many settings in embryogenesis, but also during pathological states such as cancer metastasis and lung fibrosis. We see to understanding sub-cellular machinery, known as the actomyosin cytoskeleton that is responsible for migration in these settings. Our studies focus on understanding how cells convert between these states, in particular, how cellular force production is increased to allow migration. Better understanding of this switch to migratory behavior has relevance for many diseases.
|Rai, Vandana; Thomas, Dustin G; Beach, Jordan R et al. (2017) Myosin IIA Heavy Chain Phosphorylation Mediates Adhesion Maturation and Protrusion in Three Dimensions. J Biol Chem 292:3099-3111|
|Thomas, Dustin; Thiagarajan, Praveena S; Rai, Vandana et al. (2016) Increased cancer stem cell invasion is mediated by myosin IIB and nuclear translocation. Oncotarget 7:47586-47592|
|Gupta, Sounak; Hau, Andrew M; Al-Ahmadie, Hikmat A et al. (2016) Transforming Growth Factor-? Is an Upstream Regulator of Mammalian Target of Rapamycin Complex 2-Dependent Bladder Cancer Cell Migration and Invasion. Am J Pathol 186:1351-60|
|Southern, Brian D; Grove, Lisa M; Rahaman, Shaik O et al. (2016) Matrix-driven Myosin II Mediates the Pro-fibrotic Fibroblast Phenotype. J Biol Chem 291:6083-95|
|Pasapera, Ana M; Plotnikov, Sergey V; Fischer, Robert S et al. (2015) Rac1-dependent phosphorylation and focal adhesion recruitment of myosin IIA regulates migration and mechanosensing. Curr Biol 25:175-86|
|Thomas, Dustin G; Yenepalli, Aishwarya; Denais, Celine Marie et al. (2015) Non-muscle myosin IIB is critical for nuclear translocation during 3D invasion. J Cell Biol 210:583-94|
|Thiagarajan, Praveena S; Hitomi, Masahiro; Hale, James S et al. (2015) Development of a Fluorescent Reporter System to Delineate Cancer Stem Cells in Triple-Negative Breast Cancer. Stem Cells 33:2114-2125|
|Crish, James; Conti, Mary Anne; Sakai, Takao et al. (2013) Keratin 5-Cre-driven excision of nonmuscle myosin IIA in early embryo trophectoderm leads to placenta defects and embryonic lethality. Dev Biol 382:136-48|
|Gupta, Sounak; Hau, Andrew M; Beach, Jordan R et al. (2013) Mammalian target of rapamycin complex 2 (mTORC2) is a critical determinant of bladder cancer invasion. PLoS One 8:e81081|
|Chandrasekharan, Unni M; Dechert, Lisa; Davidson, Uchechukwu I et al. (2013) Release of nonmuscle myosin II from the cytosolic domain of tumor necrosis factor receptor 2 is required for target gene expression. Sci Signal 6:ra60|
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