Sarah J. Fashena

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Cellular morphology is determined by the organization of the intracellular actin cytoskeleton, which is influenced by external and internal cues. Focal adhesions are sites at which the actin cytoskeleton is linked to the extracellular matrix by integrin receptor complexes. In addition to providing structural tethering points for cells, integrin receptor(More)
HEF1 (human enhancer of filamentation 1) is a member of a docking protein family that includes p130(Cas) and Efs. Through assembly of multiple protein interactions at focal adhesion sites, these proteins activate signaling cascades in response to integrin receptor binding of the extracellular matrix. The HEF1 protein is cell cycle regulated, with(More)
Cas-family proteins have been implicated as signaling intermediaries in diverse processes including cellular attachment, motility, growth factor response, apoptosis and oncogenic transformation. The three defined Cas-family members (p130Cas, HEF1/Cas-L and Efs/Sin) are subject to multiple forms of regulation (including cell-cycle- and(More)
HEF1, p130(Cas), and Efs define a family of multidomain docking proteins which plays a central coordinating role for tyrosine-kinase-based signaling related to cell adhesion. HEF1 function has been specifically implicated in signaling pathways important for cell adhesion and differentiation in lymphoid and epithelial cells. While the SH3 domains and(More)
Many cellular processes including proliferation, differentiation, motility and the outgrowth of processes are regulated by tyrosine phosphorylation of critical substrates. The catalytically opposed activities of proteintyrosine kinases and protein-tyrosine phosphatases maintain an essential balance of phosphorylation levels. In general, tyrosine(More)
Lymphotoxin (LT; also known as tumor necrosis factor-beta) is a pleiotropic cytokine whose expression is tightly regulated in most cells and is repressed prior to activation signals. In some early B cells and Abelson murine leukemia virus-transformed pre-B-cell lines, LT mRNA is constitutively expressed. To examine the molecular regulation of the LT gene in(More)
We have begun to explore the downstream signaling pathways of receptor protein tyrosine phosphatases (RPTPs) that control axon guidance decisions in the Drosophila central nervous system. We have focused our studies on the adhesion molecule-like gp150 protein, which binds directly to and is an in vitro substrate for the RPTP DPTP10D. Here we show that gp150(More)
Murine lymphotoxin (LT; TNF-beta) gene upstream regulatory elements were identified by linking fragments of 5' DNA to the chloramphenicol acetyl transferase gene. Fragment LT1 (-293 to +77 in relation to the proximal cap site) exhibited promoter activity which drove CAT expression in transfected murine fibroblasts and T lymphomas. Primer extension analysis(More)
The original two-hybrid system, an experimental approach designed to detect protein interactions, exploited the modular nature of many transcription factors. It has provided the intellectual and technical seed for the evolution of an array of innovative approaches, the application of which broadens the scope of experimentally feasible questions to include(More)