Download Target Tissue Signaling Molecule Major Response

Figure 11.0 Yeast
Figure 11.1 Communication between mating
yeast cells
Cell Communication
•Between separate
organisms
•Between cells within an
organism
Figure 11.2 Communication among bacteria
Figure 11.3 Local and long-distance cell communication in animals
Communicating cells can be
close together or far apart.
Paracrine Signaling
•Histamine released by
mast cells.
•Inflammation of nearby
tissue
•Increased secretion of
stomach acid
Figure 11.4 Communication by direct contact between cells
Three Stages of Cell Signaling
1. Reception: detection of signal
2. Transduction: signal converted to form
that yields cellular response
3. Response
Earl Sutherland
Figure 11.5 Overview of cell signaling (Layer 1)
Figure 11.5 Overview of cell signaling (Layer 2)
Figure 11.5 Overview of cell signaling (Layer 3)
Signal Reception
• Receptors
–
–
–
–
Membrane protein
On surface of cell
Specific
Ligand binds receptor causing a change in
conformation
– Signal transduction pathway initiated
• Types of membrane receptors
– G-Protein Linked Receptors
– Tyrosine kinase receptors
– Ion-channel receptors
Figure 11.6 The structure of a G-protein-linked receptor
Figure 11.7 The
functioning of a Gprotein-linked receptor
Figure 11.8 The structure and function of a tyrosine-kinase receptor
Figure 11.9 A ligand-gated ionchannel receptor
Figure 11.10 Steroid hormone interacting
with an intracellular receptor
Signal Transduction Pathways
• Process of relaying signal to produce
response.
• Often several steps/processes
• Amplification
• Involves second messengers
– Cyclic AMP (cAMP), Ca2+
• Protein Kinase: Enzyme that transfers
phosphate from ATP to a protein
• Protein Phosphatase: enzyme that removes
phosphate from a protein.
Figure 11.11 A phosphorylation cascade
Figure 11.12 Cyclic AMP
Figure 11.13 cAMP as a second messenger
Examples of Hormone-induced Cellular
Responses Mediated by cAMP
Target Tissue
Thyroid gland
Muscle
Heart
Hormone
TSH
Adrenaline
Adrenaline
Liver
Glucagon
Major Response
TH synthesis/secretion
Glycogen breakdown
Increase heart
rate/force of contract
Glycogen breakdown
Figure 11.14 The maintenance of calcium ion concentrations in an animal cell
Figure 11.15 Calcium and inositol triphosphate in signaling pathways (Layer 1)
Figure 11.15 Calcium and inositol triphosphate in signaling pathways (Layer 2)
Figure 11.15 Calcium and inositol triphosphate in signaling pathways (Layer 3)
Some Cellular Responses Mediated by G-Protein-linked
Receptors Coupled to Inositol Phospholipid Signaling
Pathway
Target Tissue
Liver
Signaling
Molecule
Vasopressin
Pancreas
Acetylcholine
Smooth Muscle
Acetylcholine
Mast cells
Antigen
Major Response
Glycogen
breakdown
Amylase
secretion
Contraction
Histamine
secretion
Figure 11.16 Cytoplasmic response to a signal: the stimulation of glycogen
breakdown by epinephrine
Figure 11.17 Nuclear response to a signal:
the activation of a specific gene by a growth
factor
Amplification of
Signal Response
Figure 11.18 The specificity of cell signaling
Figure 11.19 A scaffolding protein