BIOL 201 Lecture Notes - Lecture 24: Raf Kinase, Pancreatic Cancer, Grb2
11 Apr 2018
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Long-term signals lead to changes in the cytoplasm that change cell expression: ex: more than 100 genes trigger s-phase (gene duplication) in early-response only. Cells mount a very significant response cells make the decision to activate whole systems of genes. Growth factors (gfs) stimulate cells proliferation and survival. Ex: nerve growth factor (ngf) and epidermal growth factor (egf) Experiments by stanley cohen and rita levi-montalcini with dissected embryonic nervous tissue and cancerous tumors led to overgrowth of nerve fibers soluble, diffusible signal: conclusion: the cancer secretes an excess of something that promotes neuron growth and development. Transmembrane protein with intracellular and extracellular domain. Binding to the ligand leads to dimerization of the rtks: extracellular, transmembrane and intracellular domains of the dimers interact. This is due to a huge conformational change in the monomer (dimerization arm swings up, which allows it to interact with another arm) Two egf ligands are needed (one for both rtk: kinase domains bind and activate.
