Podcast Beta
Questions and Answers
How does the binding of a cyclin to a CDK activate the CDK?
Which cyclin peaks during the G1 phase of the cell cycle?
Which enzyme is responsible for inactivating CDKs by phosphorylation?
What is the role of CDK inhibitors (CKIs) in the regulation of the cell cycle?
Signup and view all the answers
How does phosphorylation by a CDK affect its target protein?
Signup and view all the answers
What happens to cyclin levels during the cell cycle?
Signup and view all the answers
Which cyclin peaks during the S phase of the cell cycle?
Signup and view all the answers
What is the function of Cdc25 phosphatase in the regulation of CDKs?
Signup and view all the answers
Which cyclin peaks during the G2 phase of the cell cycle?
Signup and view all the answers
Which enzyme is responsible for activating CDKs by dephosphorylation?
Signup and view all the answers
Study Notes
Cyclin-CDK Complexes
- Essential for controlling the cell cycle, comprising a cyclin and a cyclin-dependent kinase (CDK)
- Activity is tightly regulated to ensure proper cell cycle progression
Cyclin Synthesis and Degradation
- Cyclins are synthesized and degraded in a precise pattern during the cell cycle
- Levels fluctuate, with each type peaking at different stages to promote specific cell cycle events
- Example: cyclin D peaks during G1, cyclin E during G1/S transition, cyclin A during S and G2, and cyclin B during M phase
CDK Activation
- CDKs are activated by binding of a cyclin
- Binding changes CDK conformation, exposing its active site and allowing phosphorylation of target proteins
- Phosphorylation can either activate or inactivate target proteins, leading to cell cycle progression
CDK Inhibitors (CKIs)
- Proteins that bind to cyclin-CDK complexes and inhibit their activity
- Serve as a checkpoint mechanism to prevent cell cycle progression under conditions like DNA damage or incomplete replication
Phosphorylation Regulation
- CDKs are regulated by phosphorylation
- Inactivated by phosphorylation at specific sites by Wee1 kinase
- Activated by dephosphorylation by Cdc25 phosphatase
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the mechanisms involved in regulating cyclin-dependent kinase (CDK) complexes, crucial for controlling the cell cycle. Learn about how cyclin synthesis and degradation are intricately balanced to ensure proper cell cycle progression.
