Immunology

Insights into a versatile molecular death switch

The enzyme caspase-8 induces a molecular cell death programme called pyroptosis without involving its enzymatic activity, a new study by Hamid Kashkar published in Nature shows. In order to safeguard healthy and functioning ...

Medical research

Resist! TAK1 enables endothelial cells to avoid apoptosis

Cell death is an important aspect of tissue homeostasis, as well as inflammation and disease pathogenesis related to infection, injury, and tumor growth. Tumor necrosis factor-α (TNFα) coordinates cell death in a variety ...

Genetics

Why does making new egg cells require so much cell death?

A highly detailed study of how the roundworm C. elegans forms oocytes suggests that the egg-making process leads to the formation and subsequent destruction of cells with an extra nucleus, but that some cellular materials ...

Oncology & Cancer

'Lone wolf' protein offers new pathway to cancer treatments

Structural biologists at St. Jude Children's Research Hospital have discovered how a key protein functions to trigger cell's suicide machinery, called apoptosis. The scientists found that the protein, called BOK, is controlled ...

Oncology & Cancer

Study shows how an opportunistic microbe kills cancer cells

New study results show for the first time how dying cells ensure that they will be replaced, and suggests an ingenious, related new approach to shrinking cancerous tumors. A research team from Rush University Medical Center ...

Diseases, Conditions, Syndromes

A 'release and kill' strategy may aid treatment of tuberculosis

Mycobacterium tuberculosis has been called "the perfect pathogen." These bacteria hijack human macrophages, persist inside the cells to evade immune destruction, and then prevent the macrophage from undergoing programmed ...

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Apoptosis

Apoptosis ( /ˌæpəˈtoʊsɪs/) is the process of programmed cell death (PCD) that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. (See also Apoptosis DNA fragmentation.) Unlike necrosis, apoptosis produces cell fragments called apoptotic bodies that phagocytic cells are able to engulf and quickly remove before the contents of the cell can spill out onto surrounding cells and cause damage.

In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis, in general, confers advantages during an organism's life cycle. For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate. Between 50 and 70 billion cells die each day due to apoptosis in the average human adult. For an average child between the ages of 8 and 14, approximately 20 billion to 30 billion cells die a day.

Research in and around apoptosis has increased substantially since the early 1990s. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in an extensive variety of diseases. Excessive apoptosis causes atrophy, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer.

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