Chapter 21, Problem 16RTC

Summary Introduction

(a)

To write:

Effect of mutation in Bad such that it cannot be phosphorylated on apoptosis.

Introduction:

Bad gene is both a positive and negative regulator of apoptosis. When non-phosphorylated it binds to Bcl-2 protein and prevents its anti-apoptotic activity. However, a phosphorylated Bad cannot bind to Bcl-2

Summary Introduction

(b)

To write:

Effect of overexpression of Bcl-2 on apoptosis.

Introduction:

Bcl-2 is a negative regulator of apoptosis and the overexpression of Bcl-2 blocks the movement of cytochrome-c from the mitochondrial membrane to the cytosol.

Summary Introduction

(c)

To write:

Effect of mutation in Bax gene such that it cannot form homodimers.

Introduction:

Bax if the first pro-apoptotic gene to be discovered. Its sequence is somewhat related to the Bcl-2 and CED-9 gene both of which are known to be the suppressor of apoptosis. However, overexpression of Bax gene can cause cell death.

Summary Introduction

To write:

Which of the mutations discussed above are likely to be present in cancer cells.

Introduction:

Cells that undergo uncontrolled cell division and have the ability to metastasize to other parts of the body are known as cancer cells. These cells have lost the ability to undergo apoptosis as they do not die and keep of dividing.