Chapter 5 Signaling Molecules and Mechanisms How Do Cells Communicate with other Cells to Coordinate Processes Where are we going Today Mechanisms of intercellular communica on and signal transduc on mechanisms Next Few Classes Anatomy of the endocrine system and how its uses chemical messengers to regulate Energy Balance Diabetes Body Temperature Growth etc Mechanisms of Intercellular Communica on The movement of ions and small molecules through gap junc ons allows two cells to directly communicate electrical signals Most oMen cells communicate via chemical messengers released into the inters al uid Func onal Classes of Chemical Messengers Synap c secreted by neurons which then di uses a very short distance to bind receptors on a post synap c cell Paracrine secreted by one cell and di use to a nearby target cell Hormones secreted by endocrine cells which di uses into the blood stream for transport to target cells in the body Histamine Chemical Classi ca on of Messengers Synthesis and Release of Chemical Messengers Synthe c Pathway for Steroids Transport of Messengers Receptor Speci city Signal Recep on and Processing Ac ons of Lipophilic Hormones Classes of Membrane Bound Receptors Channel Linked Receptors The binding of a messenger to the receptor causes a conforma onal change in the channel opening it Enzyme Linked Receptors 1 Messenger binds to receptor changing its conforma on 2 This ac vates the tyrosine kinase ac vity 3 Kinase then catalyzes the phosphoryla on of an intracellular protein 4 Results in a response in the cell G Protein Linked Receptors cAMP Second Messenger System Extracellular uid Messenger 1 Receptor 2 GDP GTP GDP GTP Ampli er 3 enzyme Substrate Second messenger AcFvates enzyme 4 Protein kinase 5 Protein ATP Protein P ADP 6 Cytosol Response in cell G Protein Linked Receptors PhosphaFdylinositol Second Messenger System Messenger 1 Extracellular uid Receptor Phospholipase C 2 Cytosol GDP G protein 3 GTP 4a PIP2 GDP GTP DAG IP3 5b Protein kinase C 5a ATP protein Ca2 as second 6c messenger Calmodulin Lumen of endoplasmic reFculum Protein kinase Membrane of endoplasmic reFculum b PhosphaFdylinositol second messenger system Phosphorylates protein ADP Protein P 6b 6a Response in cell Response in cell contracFon secreFon Response in cell contracFon metabolism transport Second messengers allow for signal ampli ca on Second Messenger Systems
View Full Document
Unlocking...