To end cell division, cyclin must be degraded in order to turn off MPF (to remove cyclin from CDK). Density dependent inhibition and anchorage dependence Cancer abnormal growth, no checkpoints – Benign vs. malignant tumor Cell communication Types Direct Local (paracrine) Long distance Hormones Pheromones Signal transduction pathway 1. Reception Ligand binds to receptor (1 ligand goes to 1 type of receptor) Causes conformational shape change in receptor Types of Receptors. G-Protein Linked Receptor (most common) Ligand attaches to G-Protein linked receptor which changes shape Shape change causes phosphorylation of GDP to GTP on G-protein (similar to ADP to ATP) which activates Activated G-protein travels and turns on the appropriate enzyme or protein Tyrosine-Kinase receptor (remember that kinase = enzyme that phosphorylates something) Works in growth and emergency repair because it phosphorylates 6 things at once (so works faster) Ligand binds to two separate tyrosine kinase receptors. They join to form a dimer. This timer is phosphorylated by 6 different ATP. This receptor acts directly as an enzyme is different than a G-protein linked receptor which simply turned on the G-protein) Ion Channels / receptors
To end cell division, cyclin must be degraded in order to turn off MPF (to remove cyclin from CDK). Density dependent inhibition and anchorage dependence Cancer – abnormal growth, no checkpoints Benign vs. malignant tumor Cell communication Types Direct Local (paracrine) Long distance Hormones Pheromones Signal transduction pathway 1. Reception Ligand binds to receptor (1 ligand goes to 1 type of receptor) Causes conformational shape change in receptor Types of Receptors. G-Protein Linked Receptor (most common) Ligand attaches to G-Protein linked receptor which changes shape Shape change causes phosphorylation of GDP to GTP on G-protein (similar to ADP to ATP) which activates Activated G-protein travels and turns on the appropriate enzyme or protein Tyrosine-Kinase receptor (remember that kinase = enzyme that phosphorylates something) Works in growth and emergency repair because it phosphorylates 6 things at once (so works faster) Ligand binds to two separate tyrosine kinase receptors. They join to form a dimer. This timer is phosphorylated by 6 different ATP. This receptor acts directly as an enzyme is different than a G-protein linked receptor which simply turned on the G-protein) Ion Channels / receptors
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