The two ends of microfilament polymerize at different rates:

fast-growing end - plus end

slow-growing end - minus end

TLS Online TPP Program

#Id: 1486

#Unit 4. Cell Communication and Cell Signaling

When DNA is damaged, p53 is tetramerized and accumulates rapidly.

TLS Online TPP Program

#Id: 1487

#Unit 4. Cell Communication and Cell Signaling

The tumor suppressor proteins p53 and Rb act as guardians of the cell cycle.

TLS Online TPP Program

#Id: 1488

#Unit 4. Cell Communication and Cell Signaling

The DNA damage checkpoint controlled by p53.

TLS Online TPP Program

#Id: 1489

#Unit 4. Cell Communication and Cell Signaling

p53,  Induces the expression of CDK inhibitor p21 Induces apoptosis

TLS Online TPP Program

#Id: 1490

#Unit 4. Cell Communication and Cell Signaling

p53 transcription is upregulated by growth factor stimulation, as the cell begins preparation for its trip through GI and the important GI to S transition.

TLS Online TPP Program

#Id: 1491

#Unit 4. Cell Communication and Cell Signaling

p53 protein product is regulated by a protein called MDM2, which works through a negative feedback loop.