1 / 36

Communication, Integration, and Homeostasis

Communication, Integration, and Homeostasis. 6. About this Chapter. Cell-to-cell communication Signal pathways Novel signal molecules Modulation of signal pathways Control pathways Response loops Feedback loops. Cell-to-Cell Communication: Overview. Physiological signals

alena
Télécharger la présentation

Communication, Integration, and Homeostasis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Communication, Integration,and Homeostasis 6

  2. About this Chapter • Cell-to-cell communication • Signal pathways • Novel signal molecules • Modulation of signal pathways • Control pathways • Response loops • Feedback loops

  3. Cell-to-Cell Communication: Overview • Physiological signals • Electrical signals • Changes in cell’s membrane potential • Chemical signals • Secreted by cells into ECF • Responsible for most communication within the body • Target cells, or targets, receive signals • Four basic methods of communication

  4. Cell-to-Cell Communication: Methods Direct contact and local cell-to-cell communication Gap junctions transfer both chemical and electrical signals Figure 6-1a

  5. Cell-to-Cell Communication: Methods Direct contact and local cell-to-cell communication CAMs transfer signals in both directions Figure 6-1b

  6. Cell-to-Cell Communication: Methods Paracrine and autocrine are chemical signals Figure 6-1c

  7. Cell-to-Cell Communication: Methods Long distance cell-to-cell communication Figure 6-2a

  8. Cell-to-Cell Communication: Methods Neurotransmitters have a rapid effect Figure 6-2b

  9. Cell-to-Cell Communication: Methods Figure 6-2c

  10. Signal Pathways: Overview Figure 6-3

  11. Signal Pathways: Receptor locations Target cell receptors Figure 6-4 (1 of 2)

  12. Signal Pathways: Receptor locations Figure 6-4 (2 of 2)

  13. Signal Pathways: Membrane Receptors Four categories of membrane receptors Figure 6-5

  14. Signal Pathways: Signal Amplification Transducers convert extracellular signals into intracellular messages which create a response Figure 6-7

  15. Signal Pathway: Biological Signal Transduction Figure 6-8

  16. Signal Pathway: Signal Transduction Steps of a cascade Steps of signal transduction pathway form a cascade Figure 6-9

  17. Signal Pathway: Receptor Enzymes Tyrosine kinase, an example of receptor-enzyme Figure 6-10

  18. Signal Pathway: GPCR • Membrane-spanning proteins • Cytoplasmic tail linked to G protein, a three-part transducer molecule • When G proteins are activated, they • Open ion channels in the membrane • Alter enzyme activity on the cytoplasmic side of the membrane

  19. GPCR: Adenylyl Cyclase-cAMP Signal molecule binds to G protein-linked receptor, which activates the G protein. 1 One signal molecule G protein- coupled receptor 1 Adenylyl cyclase 2 G protein turns on adenylyl cyclase, an amplifier enzyme. 2 3 ATP G protein 3 Adenylyl cyclase converts ATP to cyclic AMP. cAMP 4 4 cAMP activates protein kinase A. Protein kinase A 5 5 Protein kinase A phosphorylates other proteins, leading ultimately to a cellular response. Phosphorylated protein Cell response The G protein-coupled adenylyl cyclase-cAMP system Figure 6-11

  20. GPCR: Adenylyl Cyclase-cAMP Signal molecule binds to G protein-linked receptor, which activates the G protein. 1 One signal molecule G protein- coupled receptor 1 G protein Figure 6-11, step 1

  21. GPCR: Adenylyl Cyclase-cAMP Signal molecule binds to G protein-linked receptor, which activates the G protein. 1 One signal molecule G protein- coupled receptor 1 Adenylyl cyclase 2 G protein turns on adenylyl cyclase, an amplifier enzyme. 2 G protein Figure 6-11, steps 1–2

  22. GPCR: Adenylyl Cyclase-cAMP Signal molecule binds to G protein-linked receptor, which activates the G protein. 1 One signal molecule G protein- coupled receptor 1 Adenylyl cyclase 2 G protein turns on adenylyl cyclase, an amplifier enzyme. 2 3 ATP G protein 3 Adenylyl cyclase converts ATP to cyclic AMP. cAMP Figure 6-11, steps 1–3

  23. GPCR: Adenylyl Cyclase-cAMP Signal molecule binds to G protein-linked receptor, which activates the G protein. 1 One signal molecule G protein- coupled receptor 1 Adenylyl cyclase 2 G protein turns on adenylyl cyclase, an amplifier enzyme. 2 3 ATP G protein 3 Adenylyl cyclase converts ATP to cyclic AMP. cAMP 4 4 cAMP activates protein kinase A. Protein kinase A Figure 6-11, steps 1–4

  24. GPCR: Adenylyl Cyclase-cAMP Signal molecule binds to G protein-linked receptor, which activates the G protein. 1 One signal molecule G protein- coupled receptor 1 Adenylyl cyclase 2 G protein turns on adenylyl cyclase, an amplifier enzyme. 2 3 ATP G protein 3 Adenylyl cyclase converts ATP to cyclic AMP. cAMP 4 4 cAMP activates protein kinase A. Protein kinase A 5 5 Protein kinase A phosphorylates other proteins, leading ultimately to a cellular response. Phosphorylated protein Cell response Figure 6-11, steps 1–5

  25. GPCR: The Phospholipase C System Signal molecule Extracellular fluid 1 Membrane phospholipid Cell membrane 3 2 4 PL-C DAG PK-C Intracellular fluid Protein + Pi Receptor IP3 G protein 5 KEY Phosphorylated protein PL-C = phospholipase C DAG = diacylglycerol PK-C = protein kinase C IP3 = inositol trisphosphate ER = endoplasmic reticulum Ca2+ stores Ca2+ ER Cellular response 1 2 3 4 5 DAG activates protein kinase C (PK-C), which phosphorylates proteins. IP3 causes release of Ca2+ from organelles, creating a Ca2+ signal. Signal molecule activates receptor and associated G protein. G protein activates phospholipase C (PL-C), an amplifier enzyme. PL-C converts membrane phospholipids into diacylglycerol (DAG), which remains in the membrane, and IP3, which diffuses into the cytoplasm. Figure 6-12

  26. GPCR: The Phospholipase C System Signal molecule Extracellular fluid 1 Cell membrane Intracellular fluid Receptor G protein KEY PL-C = phospholipase C DAG = diacylglycerol PK-C = protein kinase C IP3 = inositol trisphosphate ER = endoplasmic reticulum 1 Signal molecule activates receptor and associated G protein. Figure 6-12, step 1

  27. GPCR: The Phospholipase C System Signal molecule Extracellular fluid 1 Cell membrane 2 PL-C Intracellular fluid Receptor G protein KEY PL-C = phospholipase C DAG = diacylglycerol PK-C = protein kinase C IP3 = inositol trisphosphate ER = endoplasmic reticulum 1 2 Signal molecule activates receptor and associated G protein. G protein activates phospholipase C (PL-C), an amplifier enzyme. Figure 6-12, steps 1–2

  28. GPCR: The Phospholipase C System Signal molecule Extracellular fluid 1 Membrane phospholipid Cell membrane 3 2 PL-C DAG Intracellular fluid Receptor IP3 G protein KEY PL-C = phospholipase C DAG = diacylglycerol PK-C = protein kinase C IP3 = inositol trisphosphate ER = endoplasmic reticulum 1 2 3 Signal molecule activates receptor and associated G protein. G protein activates phospholipase C (PL-C), an amplifier enzyme. PL-C converts membrane phospholipids into diacylglycerol (DAG), which remains in the membrane, and IP3, which diffuses into the cytoplasm. Figure 6-12, steps 1–3

  29. GPCR: The Phospholipase C System Signal molecule Extracellular fluid 1 Membrane phospholipid Cell membrane 3 2 4 PL-C DAG PK-C Intracellular fluid Protein + Pi Receptor IP3 G protein KEY Phosphorylated protein PL-C = phospholipase C DAG = diacylglycerol PK-C = protein kinase C IP3 = inositol trisphosphate ER = endoplasmic reticulum Cellular response 1 2 3 4 DAG activates protein kinase C (PK-C), which phosphorylates proteins. Signal molecule activates receptor and associated G protein. G protein activates phospholipase C (PL-C), an amplifier enzyme. PL-C converts membrane phospholipids into diacylglycerol (DAG), which remains in the membrane, and IP3, which diffuses into the cytoplasm. Figure 6-12, steps 1–4

  30. GPCR: The Phospholipase C System Signal molecule Extracellular fluid 1 Membrane phospholipid Cell membrane 3 2 4 PL-C DAG PK-C Intracellular fluid Protein + Pi Receptor IP3 G protein 5 KEY Phosphorylated protein PL-C = phospholipase C DAG = diacylglycerol PK-C = protein kinase C IP3 = inositol trisphosphate ER = endoplasmic reticulum Ca2+ stores Ca2+ ER Cellular response 1 2 3 4 5 DAG activates protein kinase C (PK-C), which phosphorylates proteins. IP3 causes release of Ca2+ from organelles, creating a Ca2+ signal. Signal molecule activates receptor and associated G protein. G protein activates phospholipase C (PL-C), an amplifier enzyme. PL-C converts membrane phospholipids into diacylglycerol (DAG), which remains in the membrane, and IP3, which diffuses into the cytoplasm. Figure 6-12, steps 1–5

  31. Signal Pathway: Receptor-Channel Extracellular signal molecules Ions Receptor-channels open or close in response to signal molecule binding. 1 1 G protein- coupled receptor Ion channel 2 Some channels are directly linked to G proteins. 2 G protein Other ligand-gated channels respond to intracellular second messenger. 3 Change in membrane permeability to Na+, K+, Cl– 3 Intracellular signal molecules Creates electrical signal Voltage-sensitive protein Cellular response How ions create electrical signals Figure 6-13

  32. Signal Pathway: Receptor-Channel Extracellular signal molecules Ions Receptor-channels open or close in response to signal molecule binding. 1 1 Ion channel Figure 6-13, step 1

  33. Signal Pathway: Receptor-Channel Extracellular signal molecules Ions Receptor-channels open or close in response to signal molecule binding. 1 1 G protein- coupled receptor Ion channel 2 Some channels are directly linked to G proteins. 2 G protein Figure 6-13, steps 1–2

  34. Signal Pathway: Receptor-Channel Extracellular signal molecules Ions Receptor-channels open or close in response to signal molecule binding. 1 1 G protein- coupled receptor Ion channel 2 Some channels are directly linked to G proteins. 2 G protein Other ligand-gated channels respond to intracellular second messenger. 3 3 Intracellular signal molecules Figure 6-13, steps 1–3

  35. Signal Pathway: Receptor-Channel Extracellular signal molecules Ions Receptor-channels open or close in response to signal molecule binding. 1 1 G protein- coupled receptor Ion channel 2 Some channels are directly linked to G proteins. 2 G protein Other ligand-gated channels respond to intracellular second messenger. 3 Change in membrane permeability to Na+, K+, Cl– 3 Intracellular signal molecules Creates electrical signal Voltage-sensitive protein Cellular response Figure 6-13

  36. Signal Pathway: Signal Transduction Summary map of signal transduction systems Figure 6-14

More Related