Cell Division and Apoptosis III

Chapter 17

Activation of a cyclin dependent kinase

CdK activity can be suppressed by inhibitory phosphorylation

CdK activity can be suppressed by inhibitory proteins

The Rb protein acts as a brake in mammalian cells

Programmed Cell Death - Apoptosis

Digits in developing mouse paw are formed through apoptosis

cells undergoing apoptosis

Apoptosis causes tadpole to lose tail

Necrosis vs. apoptosis

DVD clip 77

Caspase cascade occurs during apoptosis

Procaspase is activated by an active caspase

4 types of intercellular signaling

An animal cell depends on extracellular signals to survive or divide

An animal cell depends on extracellular signals to differentiate. Without extracellular signals the

cell will die

Platelet derived growth factor was the first mitogen isolated

stimulates cell division during wound healing

Mitogens stimulate G1-Cdk and G1/S-Cdk activities

Ras is activated by tyrosine kinase

p27 suppresses CdK activity

The Rb protein acts as a brake in mammalian cells

Excessive stimulation of mitogenic pathways leads to cell cycle arrest or apoptosis

Cell growth like cell division is also stimulated by extracellular signals

Comparison of nerve cell size vs. lymphocyte size

Fresh medium stimulates cell growth by adding mitogens

Many types of normal animal cells need anchorage to grow and proliferate

cell on small patch cell spread on large patch

Myostatin inhibits proliferation of skeletal muscle cells