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Cell Communication

Cell Communication. Chapter 9. Fig. 9.1. Fig. 9.2. Fig. 9.2.a. Fig. 9.2.b. Fig. 9.2.c. Fig. 9.2.d. Fig. 9.3. Fig. 9.4.a. Fig. 9.4.b. Fig. 9.4.c. Fig. 9.5. Fig. 9.6. Fig. 9.7. Fig. 9.8. Fig. 9.8.a. Fig. 9.8.b. Fig. 9.9. Fig. 9.10. Fig. 9.11. Fig. 9.12. Fig. 9.13. Fig. 9.14.

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Cell Communication

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  1. Cell Communication Chapter 9

  2. Fig. 9.1

  3. Fig. 9.2

  4. Fig. 9.2.a

  5. Fig. 9.2.b

  6. Fig. 9.2.c

  7. Fig. 9.2.d

  8. Fig. 9.3

  9. Fig. 9.4.a

  10. Fig. 9.4.b

  11. Fig. 9.4.c

  12. Fig. 9.5

  13. Fig. 9.6

  14. Fig. 9.7

  15. Fig. 9.8

  16. Fig. 9.8.a

  17. Fig. 9.8.b

  18. Fig. 9.9

  19. Fig. 9.10

  20. Fig. 9.11

  21. Fig. 9.12

  22. Fig. 9.13

  23. Fig. 9.14

  24. Fig. 9.15

  25. Fig. 9.16

  26. Fig. 9.17

  27. Fig. 9.17.a(left)

  28. Fig. 9.17.a(right)

  29. Fig. 9.17.b(left)

  30. Fig. 9.17.b(right)

  31. Fig. 9.17.c(left)

  32. Fig. 9.17.c(right)

  33. Fig. 9.18

  34. Fig. 9.19

  35. Cell Communication Direct contact – molecules on the surface of one cell are recognized by receptors on the adjacent cell

  36. Cell Communication Paracrine signaling – signal released from a cell has an effect on neighboring cells

  37. Cell Communication Endocrine signaling – hormones released from a cell affect other cells throughout the body

  38. Cell Communication Synaptic signaling – nerve cells release the signal (neurotransmitter) which binds to receptors on nearby cells

  39. Cell Communication Communication between cells requires: ligand: the signaling molecule receptor protein: the molecule to which the receptor binds -may be on the plasma membrane or within the cell

  40. Cell Communication There are four basic mechanisms for cellular communication: 1. direct contact 2. paracrine signaling 3. endocrine signaling 4. synaptic signaling

  41. Cell Communication When a ligand binds to a receptor protein, the cell has a response. signal transduction: the events within the cell that occur in response to a signal Different cell types can respond differently to the same signal.

  42. Cell Communication A cell’s response to a signal often involves activating or inactivating proteins. Phosphorylation is a common way to change the activity of a protein. protein kinase – an enzyme that adds a phosphate to a protein phosphatase – an enzyme that removes a phosphate from a protein

  43. Receptor Types Receptors can be defined by their location. intracellular receptor – located within the cell cell surface receptoror membrane receptor – located on the plasma membrane to bind a ligand outside the cell

  44. Receptor Types There are 3 subclasses of membrane receptors: 1. channel linked receptors – ion channel that opens in response to a ligand 2. enzymatic receptors – receptor is an enzyme that is activated by the ligand 3. G protein-coupled receptor – a G-protein (bound to GTP) assists in transmitting the signal

  45. Intracellular Receptors steroid hormones -have a nonpolar, lipid-soluble structure -can cross the plasma membrane to a steroid receptor -usually affect regulation of gene expression An inhibitor blocks the receptor from binding to DNA until the hormone is present.

  46. Intracellular Receptors A steroid receptor has 3 functional domains: 1. hormone-binding domain 2. DNA binding domain 3. domain that interacts with coactivators to affect gene expression

  47. Receptor Kinases receptor tyrosine kinases -membrane receptor -when bound by a ligand, the receptor is activated by dimerization and autophosphorylation -activated receptor adds a phosphate to tyrosine on a response protein -an example is the insulin receptor

  48. Receptor Kinases kinase cascade – a series of protein kinases that phosphorylate each other in succession -amplifies the signal because a few signal molecules can elicit a large cell response mitogen-activated protein (MAP) kinasesare activated by kinase cascades

  49. G-Protein Coupled Receptors G-protein – protein bound to GTP G-protein-coupled receptor (GPCRs) – receptors bound to G proteins -G-protein is a switch turned on by the receptor -G-protein then activates an effector protein (usually an enzyme)

  50. G-Protein Coupled Receptors Once activated, the effector protein produces a second messenger. -second messenger generates the cellular response to the original signal For example – one common effector protein is adenylyl cyclase which produces cAMP as a second messenger. Other second messengers: inositol phosphates, calcium ions (Ca2+)

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