CHEM 1103 Lecture Notes - Lecture 14: Cell Membrane, Tyrosine, Glucose Transporter

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Lecture 14: cell signaling part 3: enzyme-linked receptors, enzyme-linked receptors are transmembrane proteins with their ligand-binding domain on the outer surface of the plasma membrane. Cytosolic domain either has an intrinsic kinase activity or associates directly with a kinase: each subunit of an enzyme-linked receptor usually has only one transmembrane a helix (not 7). Monday, september 10, 2018: activation of rtk activates ras signaling pathway, ras = proto-oncogene; mutated ras = oncogene. All receptor tyrosine kinases are coupled to ras (monomeric gtp binding protein). Ras functions as a molecular switch: when in its active state, it promotes the activation of a phosphorylation cascade to carry a signal from the plasma membrane to the nucleus. About 30% of human cancers have ras mutations (where it is overactive). Could stimulate cell proliferation, promote cell survival, or control cell differentiation. Monday, september 10, 2018: rtk example: insulin receptor.