Previously:. --Background on Werner’s syndrome --Hayflick His persistence and his ‘limit’ -- Theories of cellular aging -- Introduction to the cell cycle Now: -- More Cell Cycle How is it controlled? Checks and Balances Balancing cell proliferation and cell death.
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--Background on Werner’s syndrome
His persistence and his ‘limit’
-- Theories of cellular aging
-- Introduction to the cell cycle
-- More Cell Cycle
How is it controlled? Checks and Balances
Balancing cell proliferation and cell death
Basic controls needed
ensure correct order of events
work like binary switches
Why are these characteristics important?
Khodjakov & Rieder and ‘checkpoints’–
They aren’t something that is ‘activated’. The security system is always on — ‘normal’ range of activity and even quick fixes that reset are allowed
What needs to be checked for?
presence of nutrients
presence of space
presence of cell growth signals
absence of inhibitory signals
removing negative blocks
activation of steps by
checking for damage before continuing
Mitotic checkpoint and chromosome #
Why/How could this be more effective than
using an accumulation of positive signals?
Complex can only be active when together.
Complex only together when cyclins present.
CAK (Cdk activating kinase) and
CKI (cyclin kinase inhibitors) act on formed
complexes to regulate function
DNA damage and p53 stability
Overview of Cell Cycle regulation ‘complete’
Next: Looking at the different hypotheses for
the molecular reasons for aging