Cell to Cell Communication via G-Protein Linked Receptors Thursday, January 03, 2019 Cell to Cell Communication via G-Protein Linked Receptors Packet #19 Chapter #11

Introduction Thursday, January 03, 2019Thursday, January 03, 2019 G-protein-linked receptors and enzyme-linked receptors are used by practically every cell type of the body G-protein linked receptors form the largest family of cell-surface receptors G-protein-linked receptors are not found in bacteria Signals received by G-protein-linked, or enzyme- linked receptors are transmitted to elaborate relay systems formed from cascades (a series) of intracellular signaling molecules

Introduction II G-protein-linked receptors Thursday, January 03, 2019Thursday, January 03, 2019 G-protein-linked receptors Mediate responses to an enormous diversity of extracellular signal molecules Hormones Local mediators Neurotransmitters

G-Protein-Linked Receptors Thursday, January 03, 2019Thursday, January 03, 2019 Bound ligand initiates a series of reactions that ultimately result in a specific intracellular response Ligand Molecule, such as a hormone or a neurotransmitter, that binds to a specific site on a protein. Intracellular messenger systems, using cell receptors, function as signal amplification Active receptor can activate many effector molecules

G Protein Linked Receptors Thursday, January 03, 2019Thursday, January 03, 2019

Second Messenger Molecules Thursday, January 03, 2019Thursday, January 03, 2019 G Proteins activate second messengers Are small, nonprotein, water-soluble molecules or ions Intervene between original message and the ultimate effect of the cell Part of the cascade of events that translate binding hormone, or neurotransmitter, into a cellular response Two mostly recognized second messenger systems Adenylate cyclase system Calcium/phosphatidylinositol system

cAMP Second Messenger Thursday, January 03, 2019Thursday, January 03, 2019

Cyclic Adenosine Monophosphate Thursday, January 03, 2019Thursday, January 03, 2019

Calcium ions and Inositol Triphosphate (IP3) Thursday, January 03, 2019Thursday, January 03, 2019 Calcium, when released into the cytosol of a cell Acts as a second messenger in many different pathways Calcium is an important second messenger Because cells are able to regulate its concentration in the cytosol

Calcium ions and Inositol Triphosphate (IP3) II Thursday, January 03, 2019Thursday, January 03, 2019

Calcium ions and Inositol Triphosphate (IP3) III Thursday, January 03, 2019Thursday, January 03, 2019

Thursday, January 03, 2019Thursday, January 03, 2019