BIOS5030 Apoptosis Flashcards

Flashcards on Apoptosis

Apoptosis

Form of programmed cell death, different from necrosis. Cell shrinks and is consumed by nearby cells.

Necrosis

Cell death caused by acute injury. Cell swells and bursts, spilling its contents and causing inflammation.

Programmed cell death

Death at a specific time in a developmental pathway; defined by morphological features (apoptosis).

Apoptosis Stimulation

Can be stimulated by growth factor withdrawal, DNA damage, cytoskeletal damage, ER dysfunction, heat/cold shock, oxidative stress, metal stress, removal of adherent cells, immune response, or tissue ischemia.

Caspase 9-deficient mice

Results in overproliferation of brain neurons and thickened ventricle walls.

Ced genes

Family of genes involved in controlling programmed cell death, with some involved in engulfment; mutation of ced3 or ced4 results in excess cells.

Caspases

Cysteine proteases that cleave target proteins C-terminal to aspartic acid residues, acting in a cascade for signal amplification.

Apoptosis Markers

Distinct changes in cells undergoing apoptosis, including membrane blebbing, nuclear morphology changes, chromatin changes, and engulfment by adjacent cells.

Apoptosis Pathways

Two main pathways, death receptor (extrinsic) and mitochondrial (intrinsic), which can coordinate; cell death can occur via either mechanism under certain stimuli.

Bcl2

A family of proteins that regulate the intrinsic pathway of apoptosis, preventing activation of pro-apoptotic family members.

Cytochrome C Release

Activation of mitochondrial membrane localized pro-apoptotic Bcl2 family members leads to release of proteins such as cytochrome C.

Apaf1

Apoptotic protease activating factor 1. Release of cytochrome C leads to activation of Apaf1 and assembly of apoptosomes that recruit and activate caspases.

Extrinsic Pathway Activation

The death receptor pathway of apoptosis can engage mitochondrial outer membrane permeabilisation through the cleavage of the BH3-only protein Bid.

Survival Factors

Examples being nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) and these neurons degenerate by apoptosis.