Understanding Apoptosis: The Death of Cells
Apoptosis, also known as programmed cell death, is an important process that helps keep our tissues healthy. It happens through two main ways: the extrinsic pathway and the intrinsic pathway.
How It Starts: The extrinsic pathway kicks in when external signals tell cells to die. This mainly happens when certain molecules, called ligands, attach to special receptors on the cell's surface. Some well-known receptors in this pathway are Fas (CD95) and TRAIL receptors.
Caspase Activation: When these ligands attach to the receptors, they call for a helper protein named FADD. Together, they form a group known as the death-inducing signaling complex (or DISC). This process mainly activates a protein called caspase-8 first, which then activates other proteins like caspase-3 to carry on the process of cell death.
Did You Know?: It’s estimated that about 40% of cell deaths happen through this extrinsic pathway, which is very important in how our immune system works.
How It Starts: The intrinsic pathway is different because it starts from problems inside the cell. These issues can include things like damage to the cell’s DNA or other types of stress. This pathway involves changes in the mitochondria, the cell's powerhouses.
Caspase Activation: In this pathway, proteins from the Bcl-2 family play a big role. Some of these proteins, like Bax and Bak, help release a molecule called cytochrome c from the mitochondria. When cytochrome c is released, it forms a group with another protein called Apaf-1, which activates caspase-9. This further leads to the activation of caspase-3, continuing the cell death process.
Did You Know?: About 60% of cell deaths are believed to come from the intrinsic pathway, which shows just how important it is in responding to stress and helping cells develop properly.
Where the Signals Come From:
How Caspases are Activated:
What They Do:
In summary, both the extrinsic and intrinsic pathways are crucial for the process of apoptosis. They help maintain the health of our cells and respond appropriately when things go wrong.
Understanding Apoptosis: The Death of Cells
Apoptosis, also known as programmed cell death, is an important process that helps keep our tissues healthy. It happens through two main ways: the extrinsic pathway and the intrinsic pathway.
How It Starts: The extrinsic pathway kicks in when external signals tell cells to die. This mainly happens when certain molecules, called ligands, attach to special receptors on the cell's surface. Some well-known receptors in this pathway are Fas (CD95) and TRAIL receptors.
Caspase Activation: When these ligands attach to the receptors, they call for a helper protein named FADD. Together, they form a group known as the death-inducing signaling complex (or DISC). This process mainly activates a protein called caspase-8 first, which then activates other proteins like caspase-3 to carry on the process of cell death.
Did You Know?: It’s estimated that about 40% of cell deaths happen through this extrinsic pathway, which is very important in how our immune system works.
How It Starts: The intrinsic pathway is different because it starts from problems inside the cell. These issues can include things like damage to the cell’s DNA or other types of stress. This pathway involves changes in the mitochondria, the cell's powerhouses.
Caspase Activation: In this pathway, proteins from the Bcl-2 family play a big role. Some of these proteins, like Bax and Bak, help release a molecule called cytochrome c from the mitochondria. When cytochrome c is released, it forms a group with another protein called Apaf-1, which activates caspase-9. This further leads to the activation of caspase-3, continuing the cell death process.
Did You Know?: About 60% of cell deaths are believed to come from the intrinsic pathway, which shows just how important it is in responding to stress and helping cells develop properly.
Where the Signals Come From:
How Caspases are Activated:
What They Do:
In summary, both the extrinsic and intrinsic pathways are crucial for the process of apoptosis. They help maintain the health of our cells and respond appropriately when things go wrong.