What are the mechanism of apoptosis?

apoptosis, also called programmed cell death, in biology, a mechanism that allows cells to self-destruct when stimulated by the appropriate trigger. Apoptosis can be triggered by mild cellular injury and by various factors internal or external to the cell; the damaged cells are then disposed of in an orderly fashion.

What are the 5 steps of apoptosis?

Major steps of apoptosis:

  • Cell shrinks.
  • Cell fragments.
  • Cytoskeleton collapses.
  • Nuclear envelope disassembles.
  • Cells release apoptotic bodies.

What are the four stages of apoptosis?

To illustrate these apoptosis events and how to detect them, Bio-Rad has created a pathway which divides apoptosis into four stages: induction, early phase, mid phase and late phase (Figure 1).

What is the apoptotic pathway?

The intrinsic and extrinsic pathways of apoptosis are both naturally occurring processes by which a cell is directed to programmed cell death. Both pathways of apoptosis activate cell signaling cascades that are an indispensable part of the development and function of an organism.

What causes cell apoptosis?

Sudden removal of the survival signals or disassociation from neighboring cells will cause a cell to initiate apoptosis. Moreover, increased cellular stress such as exposure to high heat conditions, DNA damage caused by irradiation/chemotherapy or pathogenic infection can also lead to cell death by apoptosis.

What are the mechanism of cell injury?

Cell injury and adaptation The responses induced by cellular injury fall into four main patterns: the ischaemic/anoxic, oxidative, heat shock and acute phase responses.

What is the first step of apoptosis?

The key step in apoptosis is the release of the protein cytochrome c and other apoptotic factors from the mitochondria into the cell interior. After this step, apoptosis induction is irreversible and cell’s fate is sealed. In order to allow this process, the mitochondrial membrane must be permeable.

Which organelle is involved in apoptosis?

Mitochondria
Mitochondria are pivotal in the control of apoptosis, being involved not only in the intrinsic but also in the extrinsic pathway.

How many pathways are there in apoptosis?

two
The two main pathways of apoptosis are extrinsic and intrinsic as well as a perforin/granzyme pathway. Each requires specific triggering signals to begin an energy-dependent cascade of molecular events.

What pathways are activated in response to an apoptotic signal?

There are at least three different kinds of pathways participate in apoptosis initiation: death receptor signaling pathway, mitochondrial pathway and endoplasmic reticulum(ER) stress pathway. As a pathway is more or less sequential in nature, removing or modifying one component leads to an effect in another.

What activates apoptosis in cells that are damaged?

Apoptosis is mediated by proteolytic enzymes called caspases, which trigger cell death by cleaving specific proteins in the cytoplasm and nucleus. Caspases exist in all cells as inactive precursors, or procaspases, which are usually activated by cleavage by other caspases, producing a proteolytic caspase cascade.