Apoptosis and Programmed Cell Death

Flashcards providing vocabulary terms and definitions related to apoptosis and programmed cell death, covering its mechanisms, pathways, and regulation, as well as strategies used by cancer cells to evade it.

Apoptosis (Programmed Cell Death)

A mechanism for removing cells or tissues that are no longer needed, damaged, or infected, which is a natural process during development.

Blebbing of PM

A morphological feature observed during apoptosis, referring to the outward protrusions of the plasma membrane.

Pyknosis

Nuclear condensation, a morphological feature of apoptosis.

Golgi fragmentation

A morphological feature observed during apoptosis where the Golgi apparatus breaks into smaller pieces.

DNA Fragmentation

A biochemical feature of apoptosis where the cell's DNA is cleaved into smaller pieces.

Caspases

A family of proteins (Cysteine aspartic acid proteases) that mediate apoptosis by cleaving their substrates after an aspartate residue.

Procaspases

The catalytically inactive forms in which caspases are initially produced.

Caspase activation

Occurs as a result of proteolytic cleavage of procaspases.

Initiator Caspases

A type of caspase present as inactive monomers that cleave inactive forms of effector caspases.

Executioner Caspases

A type of caspase that, once activated by initiator caspases, cleaves a number of cellular proteins leading to apoptosis.

ICAD (Inhibitor of Caspase Activated DNAse)

A cellular protein that is cleaved by caspases during apoptosis, releasing CAD.

CAD (Caspase Activated DNAse)

An endonuclease released after ICAD cleavage that is responsible for cleaving DNA during apoptosis.

Extrinsic Pathway of Apoptosis

An apoptotic pathway initiated by signaling that activates death receptors on the cell surface.

Death Receptors

Receptors belonging to the TNF (Tumor Necrosis Factor) receptor family that initiate the extrinsic apoptotic pathway; they have extracellular, transmembrane, and intracellular death domains and exist as homotrimers.

FADD (Fas-Associated protein with Death Domain)

An adaptor protein recruited by death receptors during the extrinsic apoptotic pathway.

DISC (Death Inducing Signaling Complex)

A complex formed when death receptors recruit adaptor proteins like FADD, leading to the activation of initiator Caspase (Caspase 8).

Caspase 8

An initiator caspase activated within the DISC during the extrinsic pathway of apoptosis.

Intrinsic Pathway of Apoptosis

An apoptotic pathway regulated by intracellular signals, often involving the mitochondria and the Bcl2 family of proteins.

Bcl2 family of proteins

Proteins that regulate apoptosis, with the balance between pro-apoptotic and anti-apoptotic members determining the cell's fate.

p53

A tumor suppressor protein that can activate apoptosis in response to DNA damage or other cellular stresses.

Anti-apoptotic strategies used by cancer cells

Mechanisms employed by cancer cells to evade apoptosis, including increased Mdm2 expression, production of FLIP, and increased levels of anti-apoptotic proteins like IAP and Bcl2.

Mdm2

A protein whose increased expression in cancer cells can serve as an anti-apoptotic strategy, often by degrading p53.

FLIP

A protein produced by cancer cells as an anti-apoptotic strategy, specifically by inhibiting caspase activation in the extrinsic pathway.

IAP (Inhibitor of Apoptosis Proteins)

Proteins whose levels are increased in cancer cells as an anti-apoptotic strategy, directly inhibiting caspase activity.