generally described about the points on apoptosis ,causes and clinical applications

1. RUCHIKA DHIMAN
GROUP-5

2. CONTENTS
• WHAT IS APOPTOSIS
• PATHWAYS OF APOPTOSIS
• APOPTOSIS: MORPHOLOGICAL
CHANGES
• APOPTOSIS IMPORTANCE

3. APOPTOSIS
• Cell apoptosis refers to the programmed cell
death controlled by genes to maintain stable
internal conditions.
• Apoptosis is an active process which involves
the activation, expression, and regulation of a
series of genes.
• It is not a form of traumatic cell death that
results from acute cellular injury, apoptosis is a
highly regulated and controlled process that
confers advantages during an organism’s life-
cycle.

4. 1) Cell shrinkage
2) Organelle reduction
3) Mitochondrial leakage
4) Chromatin condensation
5) Nuclear fragmentation
6) Membrane blebbing & changes
Apoptosis: morphological changes

5. Pathways of Apoptosis
• Intrinsic pathway-mitochondria mediated events
• Extrinsic pathway-death receptor mediated events

7. • Most of the times intrinsic pathway is initiated due to damage of DNA
in the cell.
• DNA lesions leads to the activation of ATM which activates tumor
suppressor p53 protein.
• p53 activates protein BAX which form pores on outer mitochondrial
membrane.
• This leads to leakage of calcium ion, hydrogen ions along with protein
cytochrome – c.
• Cytochrome C forms ‘Apoptosome’ by attaching to adaptor protein.
• Apoptosome activates Caspases especially caspase-9 which cleaves
other protein and activates other caspases continuing the cycle.
• Caspase also cleaves the actin cytoskeleton, causing shrinkage of the
cell and its death.

8. Extrinsic pathway is initiated by external
signal.
• Most common extrinsic factor for initiation is
TNF(alpha) secrete by T-killer
cells.
• Killler lymphocyte attaches to death
receptor’s of the diseased cell through
Fas ligands or TNF.
• The FADD adaptor protein is attached to
death receptor (in cytoplasm).
• Eventually inactivated procaspase-8 or 10
attaches to FADD to activate
itself.
• Activated caspase-8 breaks other proteins
and actin cytoskeleton bringing
the death for cell

9. Importance of apoptosis
In embryo
• During embryonic development it helps in digit formation.
• Lack of apoptosis in human beings leads to webbed fingers called
‘syndactyly’.