chapter 5. the chemical properties of a ligand predict its binding site: hydrophobic/lipid-soluble:...
TRANSCRIPT
![Page 1: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/1.jpg)
Chapter 5
![Page 2: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/2.jpg)
The chemical properties of a ligand predict its binding site:
• Hydrophobic/lipid-soluble: cytosolic or nuclear receptors
examples: steroid hormones, thyroid hormones…
• Hydrophilic/lipid-insoluble: membrane-spanning receptors
examples: epinephrine, insulin…
Chapter 5Control of Cells by Chemical Messengers
= How hormones and other signals work
Communication requires:
signals (ligands) and receptors (binding proteins).
![Page 3: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/3.jpg)
Receptors are proteins that can bind only specific ligands and they are linked to response systems.
• Hydrophobic signals typically change gene expression,
leading to slow but sustained responses.
• Hydrophilic signals typically activate rapid, short-lived
responses that can be of drastic impact.
Chapter 5Control of Cells by Chemical Messengers= How hormones and other signals work (cont.)
![Page 4: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/4.jpg)
Modes of cell communication
![Page 5: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/5.jpg)
![Page 6: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/6.jpg)
![Page 7: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/7.jpg)
Figure 5-1
EPI b i n d s h e r e
… cellular response begins …
Receptors on the surface of a cell are typically proteins that span the membrane.
Structure of the Receptor
![Page 8: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/8.jpg)
![Page 9: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/9.jpg)
Figure 5-2
Cells B & C lack the matching receptorsTherefore are not directly affected by the signal.
Only Cell A has thematching receptorsfor this chemical messenger, so it is the only one that responds.
Specificity of the Receptor
![Page 10: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/10.jpg)
Characteristic of receptor binding to messengers
![Page 11: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/11.jpg)
Signal Transduction pathways:
![Page 12: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/12.jpg)
Figure 5-4
… but at the target cellthe signal moves easily through the membraneand binds to its receptor.
This hydrophobic signal requires a carrier protein while in the plasma …
Mechanism of action of lipid soluble messengers
![Page 13: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/13.jpg)
Binding of ligands to membrane-spanning receptorsactivates diverse response mechanisms.
Figure 5-5
Mechanism of action of Lipid-insoluble messengers
![Page 14: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/14.jpg)
Binding of the ligand to the receptoralters the receptor’s shape, which then opens (or closes) an ion channel.
Figure 5-5a
Receptor act as Ion channel
![Page 15: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/15.jpg)
Binding of the ligand to the receptor alters the receptor’s shape, which activates its enzyme function, phosphorylating an intracellular protein.
Figure 5-5b
Receptor act as an Enzyme
![Page 16: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/16.jpg)
Binding of the ligand to the receptor alters the receptor’s shape, which activates an associated enzyme function, phosphorylating an intracellular
protein.
Figure 5-5c
Receptor that activates JAK kinase
![Page 17: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/17.jpg)
Binding of the ligand to the receptor alters the receptor’s shape, which activates an associated G-protein, which then activates effector proteins,i.e., enzyme functions or ion channels.
Figure 5-5d
Receptor that activates G-proteins
![Page 18: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/18.jpg)
The cyclic AMP second messenger system.
Figure 5-6
Receptor that activates G-protein:Effector is an enzyme
![Page 19: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/19.jpg)
Adenylyl cyclase forms cAMP,a “second messenger” that activates enzymes used in cellular responses.
The phosphodiesterase enzymes “terminate” thesecond messenger cAMP.
Figure 5-7
![Page 20: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/20.jpg)
Figure 5-8
The cAMP system rapidly amplifies the responsecapacity of cells: here, one “first messenger” ledto the formation of one million product molecules.
![Page 21: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/21.jpg)
Cells can respond via the cAMP pathwaysusing a diversity of cAMP-dependentenzymes, channels,organelles, contractile filaments, ion pumps, and changes in gene expression.
Figure 5-9
![Page 22: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/22.jpg)
This receptor-G-protein complex is linked to and activates phospholipase C, leading to an increase in IP3 and DAG, which work together to activate enzymes and to increase intracellular calcium levels.
Figure 5-10
Receptor that activates G-protein:Effector is an enzyme
![Page 23: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/23.jpg)
![Page 24: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/24.jpg)
![Page 25: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/25.jpg)
The calcium-calmodulinsystem is similar to some of the cAMP pathways, because it results in the activation of protein kinases that can phosphorylate key proteins required for cellular responses.
Figure 5-11
![Page 26: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/26.jpg)
The “arachidonic acid cascade” is activated in inflammation responses; “cox inhibitors” block cyclooxygenase.
Figure 5-12
Aspirin
NSAIDs
![Page 27: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/27.jpg)
Not all responses to hydrophilic signals are immediate:
Increases in gene expression can occur, and the resulting proteins can increase the target cells’ response.
Figure 5-13
Role od transcription factorIn protein synthesis
Primary response gene
![Page 28: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/28.jpg)
![Page 29: Chapter 5. The chemical properties of a ligand predict its binding site: Hydrophobic/lipid-soluble: cytosolic or nuclear receptors examples: steroid hormones,](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649f445503460f94c653dd/html5/thumbnails/29.jpg)
Thank U for UR Nice Attention,,,,