BIO315H5 Lecture Notes - Lecture 1: Inositol Trisphosphate, Cyclic Adenosine Monophosphate, Ligand-Gated Ion Channel
Document Summary
Allows organisms to respond to changes in their environment, including presence of other cells e. g. pheromone (mating) system in yeast. Pheromone system - one mate secretes a mating factor, other mate has receptor factor. Mating-deficient yeast mutants include those lacking expression of gpcrs, g proteins, kinases, etc. Kinases are sibling proteins that are part of the receptor pathway. The extracellular signal molecule (ligand) binds to the receptor on the target cell. The receptor activates intracellular signaling proteins in the cytosol to initiate a signaling cascade. Ultimately, the signaling cascade alters the activity of effector (target) proteins, thereby altering the behaviour of the cell. Effector proteins bring the desired functions, such as: Transcription regulatory protein --> altered gene expression e. g. transcription factors. Cytoskeletal protein --> altered cell shape or movement. Transduction: signal is converted from one form to another (ligand -> changes in intracellular signaling proteins)
