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Unformatted text preview: T revor Bak Alexander Darling BACKGROUN D I N FOR MAT IO N:
• Proteins in the cell membrane that partially int rude into the cytosol ( intercellular f luid) and perform signal t ransduction Signal T ransduction:
• The general concept of an extracellular molecule binding to a receptor, which t r iggers a series of reactions that help the cell perform i ts functions T YPES OF RECEP TORS
Ligand-Gated Ion Channels ( Ion T ransduction Receptors)
• • • A L igand binds to the receptor The receptor opens up a channel, allowing SPECIFIC ions to enter the cell The channel usually closes very quickly (1 to 100 milliseconds) G-P rotein Coupled Receptors
• • • • Receptor is associated with a protein (notated as Gx, where x is a placeholder for any letter ) A ligand binds to the receptor The receptor can then activate its protein by catalyzing the reaction switching G DP (a part of the protein) with GTP Activated protein then does whatever it was made to do… Metabotropic Receptors
• • • • • Combination of the above two receptors A ligand binds to a G-protein coupled receptor, which releases its protein The protein performs a specific function, releasing into the cytosol a different l igand The new ligand binds to an ion t ransduction receptor, opens up an ion channel These channels last from seconds to minutes (as opposed to the milliseconds of Ligand-gated ion channels) Ty rosine Kinase (TK Receptors) • • • • A ligand binds to the receptor The receptor attracts ATP ATP is broken down, putting phosphate groups on the tyrosine heads A kinase takes the phosphate and transfers it across multiple kinases (called a kinase cascade) until the final kinase transfers the phosphate to wherever it belongs (another open statement, but it’s true. The phosphate groups can go all sorts of places) ...
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This note was uploaded on 02/10/2011 for the course BIOLOGY 101 taught by Professor Monahan during the Fall '10 term at Bellevue College.
- Fall '10