Sarah MeyersImmunolocalization of Focal Adhesion Kinase in Nerve Growth Factor-Induced PC12-wt2 Neurogenesis
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Focal Adhesion Kinase (FAK), a 125 kDa non-receptor, protein tyrosine kinase, is known to be important in intracellular signaling cascades relating to cell adhesion and migration. Although FAK has been studied at the beginning of neurogenesis and short-term focal adhesion turnover, research into FAK’s role in adhesion during long-term neurogenesis has been limited. PC12 cells, a rat pheochromocytoma cell line, provide an ideal system to study FAK, focal adhesions and neurogenesis. PC12 cells can be induced to differentiate into a neuron-like cell and project neurite extensions from the cell body within twenty-four hours of stimulation with Nerve Growth Factor (NGF). The goal of this study was to investigate the localization of FAK and phosphorylated or kinase activated FAK in one and five day NGF stimulated PC12-wt2 cells. If FAK is essential for adhesion and migration, then localized areas known as focal adhesions and point contacts should be discernable through fluorescent immunolocalization. This research shows that sites of FAK and phosphorylated/activated FAK are discernable throughout the cytoplasm, but lacking in the nucleus, confirming that it FAK is a nonnuclear protein. Additionally, FAK and phosphorylated FAK were present in the growth cones (tips of projecting neurites) in day one and day five NGF-stimulated PC12-wt2 cells and throughout the neurites of day five NGF-stimulated PC12-wt2 cells. These localization points could indicate points of attachment between the cell and extracellular matrix as well as important areas involved in neurite migration.