|
MCB572 Cell Regulation- Modes and Features- An Ad hoc List Modes of
regulation
In this class we are striving to always strive to keep a Big Picture
in view.
We try to extract general principles from all the details.
We will NOT cover thousands of minute, forgettable details.
We will try and uncover a few underlying principles.
Pathway Features:
- + and -
- Feedback
- Networks
1. Multiple Steps
- coordinate multiple input and outputs?
- Signal amplification"all or none" decision
- achieve sigmoidal dose-response curve?
2. Thresholds - prevent signaling from background (negative regulators
on positive steps)
3. "Redundancy" overlapping gene functions
4. Steady state systems: not in equilibrium
5. Recovery vs. Adaptation- turning pathways off
6. Ramification
7. Checkpoints- ordering events (more of a development issue)
8. Cross-talk (undesirable) & connectedness (desirable) Insulation between
pathways
9. Timing- kinetic proof reading
10. Irreversibility
11. Contingency
Protein Features:
- Modules, modules, more modules
- Activity: consequence of activation, localization, substrate access
- Synthesis and degradation
- Post-translational modification - phosphorylation, ubiquitination,
etc.
- Signaling by small molecules- Ca++, GTP
- Assembly/Disassembly- -MT, actin
- Protein machines - everything?
- Movement
- Achieving specificity and preventing cross talk
- Incremental regulation vs. all or nothing
- Proteins with multiple and sometimes very different functions
Evolution of Gene Networks
- Robustness
- Modularity
- Capacitators/Evolvability.
<- Go home
|