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1. Introduction
2. Intracellular protein degradation
3. Multi-component degradation systems
4. Talk outline
5. Components of Clp proteases
6. Structure of ClpP
7. ClpP tetradecamer
8. Clp/Hsp100 chaperones
9. ClpA belongs to the AAA+ superfamily
10. Stacked ringed structure of Clp proteases
11. E. coli proteins degraded by ClpXP and ClpAP
12. Regulated degradation of the sigma factor RpoS
13. Degradation of SsrA tagged proteins by ClpXP
14. Substrates are recognized by sequence motifs
15. Motifs recognized by ClpX
16. Motifs recognized by ClpA
17. N- and C-terminal degrons are transferable
18. Protein degradation requires ATP hydrolysis
19. Protein remodeling activity of Clp chaperones
20. ClpX catalyzes unfolding of GFP-SsrA
21. Axial pathway for substrates into ClpP
22. One substrate binding site per hexamer
23. Steps in ATP-dependent protein degradation
24. Kinetics of ATP-dependent degradation
25. ClpAP is stable for multiple rounds of degradation
26. Peptide bond cleavage by ClpAP and ClpXP is fast
27. ATP hydrolysis rates are variable
28. ATP is used for unfolding and translocation
29. ATP consumed faster during rapid degradation
30. Partitioning of ATP use
31. Variable amounts of ATP used for unfolding
32. Kinetics of ClpXP protein unfolding and degradation
33. ATP cost for translocation by ClpA and ClpX
34. N-domains help and hinder protein degradation
35. Remaining questions
36. Structural basis of function and mechanism
37. Crystal structure of ClpA subunit
38. Model of ClpA hexamer
39. Sectional view of ClpA hexamer model
40. Both AAA+ domains of ClpA are functional
41. Model of ClpX hexamer
42. Loop in ClpX interacts on edge of ClpP
43. The asymmetric interaction of ClpA/X and ClpP
44. All six ClpP loops are needed to form ClpXP
45. N-terminal axial loops of ClpP
46. Consensus sequence of ClpP N-terminal axial loop
47. Activities of human ClpP N-terminal mutants
48. Mobile loops in the axial channels of ClpA
49. Low activity of D1 and D2 channel loop mutants
50. Mobile loops in the axial channel of ClpX
51. Degradation activity of ClpX channel loop mutants
52. How does ATP hydrolysis promote activity?
53. ATP binding and release produces a rotation
54. Movement of the channel loops in response to ATP
55. ClpX subunits act as individual motors
56. Random versus coupled activity of ClpX subunits
57. Bipartite mode of substrate interaction
58. Enhanced substrate interaction with adaptors
59. Adaptors: modulators of substrate binding
60. Anchoring of SspB to ClpX-ZBD
61. SsrA binds in deep groove in SspB
62. Inactive ClpP traps translocated substrates
63. 2D gel separation of trapped substrates
64. ClpX substrates trapped by ClpP-SA
65. Degradation of GFP-SsrA by ClpAP and ClpXP
66. Pull-down of SsrA-tagged proteins with ClpXP
67. Degradation of N-end rule proteins by ClpAP
68. Crystal structure of ClpS bound to ClpA-N-domain
69. Mobile N-domains of ClpA
70. N-domains help binding of unfolded proteins
71. Many remaining questions
72. Potential substrate channels between ClpP rings
73. Dysregulation of ClpP makes it lethal
74. Contributors

Topics Covered

• The Clp/Hsp100 family
• Structure of Clp complexes
• Unfolding and degradation activities of Clps
• Substrate recognition and the role of adaptors
• ATP utilization, unfolding and translocation
• Dynamics of Clp complexes
• Protein quality control and the in vivo functions of Clp chaperone/proteases

Links

Series:

• Molecular Chaperones

Categories:

• Biochemistry
• Cell Biology

Talk Citation

Maurizi, M.R. (2007, October 1). Structure and function of the ATP-dependent Clp chaperone/protease machines [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved April 15, 2025, from https://doi.org/10.69645/INAP3788.
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Publication History

• Published on October 1, 2007

Financial Disclosures

• Dr. Michael R. Maurizi has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.