You might say that caspases are obsessed with death. The primary agents of programmed cell death, or apoptosis, caspases kill cells by destroying proteins that sustain cellular processes. Apoptosis, a highly controlled sequence of events that eliminates dangerous or unnecessary cells, contributes to a wide variety of developmental and physiological processes--in a developing embryo, apoptosis creates the space between fingers and adjusts nerve cell populations to match the number of cells they target; in an adult, apoptosis counters cell proliferation to maintain tissue size and density. Now it appears that caspases may also play a role in creating life. As Bruce Hay, Jun Huh, and colleagues of the California Institute of Technology, report in this issue, multiple caspases and caspase regulators are required for the proper formation of free-swimming sperm in the fruitfly Drosophila.

Caspases, which typically exist in a quiescent state in nearly all cells, are regulated through a complex network of activators and inhibitors. Once activated, a "caspase cascade" ultimately cleaves and irreversibly alters the function of essential cellular proteins, leading to apoptosis. Not surprisingly, cells keep caspase activation under tight wraps. That's why it's intriguing that multiple caspases normally associated with the induction of cell death participate in this non-apoptotic process.

During spermatogenesis, germline precursor cells--the cells that generate sex cells--give rise to 64 haploid spermatids. Spermatids are connected by intracellular "bridges" that, along with most other cytoplasmic components, must be expelled in a process called "individualization" to create terminally differentiated free-swimming sperm. A similar process--elimination of cytoplasm and membrane packaging of individual spermatids--also occurs in mammals, and its disruption is associated with male infertility.

Hay's group studied the consequences of inhibit
'"/>

Contact: Dr. Bruce Hay
haybruce@its.caltech.edu
626-395-3399
Public Library of Science
15-Dec-2003

Page: 1 2
Related biology news :

1. Suicide Response Gives Colorado State Researchers Important Clues On Preventing Bacterial Invasion In Crops Worldwide
2. Unicellular organisms contribute more nitrogen to ocean that reported earlier
3. Does antibiotic use contribute to allergies?
4. Common virus may contribute to uncommon bone disease in children
5. Protein inhibits cell growth, may contribute to breast cancer
6. Could a specific protein contribute to erectile dysfunction for the diabetic and obese?
7. Molecule identified that contributes to essential cell functioning process
8. Swimming can contribute to rebuilding bone strength
9. Deciphering how arteries contribute to hypertension
10. UC Riverside scientists contribute to study that unveils genome sequence of bread mold
11. Stem cells contribute to tissue regeneration in mice with ALS