Cellular killer also important to memory

December 21, 2006

CHAMPAIGN, Ill. -- A protein known primarily for its role in killing cells also plays a part in memory formation, researchers at the University of Illinois at Urbana-Champaign report. Their work exploring how zebra finches learn songs could have implications for treatment of neurodegenerative conditions such as dementia and Alzheimer's disease.

When activated, the enzyme caspase-3 triggers a synaptic process essential for memory storage, according to Graham R. Huesmann and David F. Clayton of the department of cell and developmental biology and of the U. of I. Beckman Institute for Advanced Science and Technology. Their article, which appears in the Dec. 21 issue of the journal Neuron, describes their findings, which provide "the first direct evidence of a change in the availability of activated caspase-3 protein in the brain during the process of memory formation."

Caspase-3 is best known for its role in a biochemical cascade that leads to apoptotic cell death. These new findings demonstrate that the enzyme acts differently under different conditions, and suggest that its regulation in the brain is more complex than previously thought. Huesmann and Clayton examined the brains of zebra finches after exposing the birds to tape recordings of the songs of other birds. They found an increase in the concentration of activated caspase-3 in post-synaptic sites of the auditory forebrain shortly after the birds were exposed to unfamiliar bird songs. Exposure to familiar songs caused no significant increase in the enzyme.

The researchers demonstrated that the activated form of caspase-3 is short-lived and highly localized, which may explain why the enzyme does not trigger apoptosis.

They also showed that activated caspase-3 is always present in brain cells, but that it is usually bound by an inhibitor, BIRC4. For a short time after the birds are exposed to novel songs, the inhibitor releases the activated caspase-3. The concentration of unbound, activated caspase-3 peaks about 10 minutes after the birds hear the new songs.

Other research has added to the evidence that caspase-3 is essential to memory formation. Caspase-3 inhibitors injected into rat brains interfere with the animals' spatial memory and active avoidance learning.

Caspase-3's dual role as a cell killer and memory builder has long intrigued Huesmann, the lead author of the study. "Is it Memory or Is It Death? Caspase-3 and Memory Formation," was his dissertation title. Huesmann has a doctorate in neuroscience and is completing a medical degree at Illinois.

"Graham had this intuition that growth and memory is really a kind of remodeling," said Clayton, who is a professor of cell and structural biology. "You can't have growth without death."

Editor's note: To reach Graham R. Huesmann, call 217-244-1450; e-mail: huesmann@uiuc.edu.

To reach David F. Clayton, call 217-244-3668; e-mail: dclayton@uiuc.edu.

University of Illinois at Urbana-Champaign

Related Memory Articles from Brightsurf:

Memory of the Venus flytrap
In a study to be published in Nature Plants, a graduate student Mr.

Memory protein
When UC Santa Barbara materials scientist Omar Saleh and graduate student Ian Morgan sought to understand the mechanical behaviors of disordered proteins in the lab, they expected that after being stretched, one particular model protein would snap back instantaneously, like a rubber band.

Previously claimed memory boosting font 'Sans Forgetica' does not actually boost memory
It was previously claimed that the font Sans Forgetica could enhance people's memory for information, however researchers from the University of Warwick and the University of Waikato, New Zealand, have found after carrying out numerous experiments that the font does not enhance memory.

Memory boost with just one look
HRL Laboratories, LLC, researchers have published results showing that targeted transcranial electrical stimulation during slow-wave sleep can improve metamemories of specific episodes by 20% after only one viewing of the episode, compared to controls.

VR is not suited to visual memory?!
Toyohashi university of technology researcher and a research team at Tokyo Denki University have found that virtual reality (VR) may interfere with visual memory.

The genetic signature of memory
Despite their importance in memory, the human cortex and subcortex display a distinct collection of 'gene signatures.' The work recently published in eNeuro increases our understanding of how the brain creates memories and identifies potential genes for further investigation.

How long does memory last? For shape memory alloys, the longer the better
Scientists captured live action details of the phase transitions of shape memory alloys, giving them a better idea how to improve their properties for applications.

A NEAT discovery about memory
UAB researchers say over expression of NEAT1, an noncoding RNA, appears to diminish the ability of older brains to form memories.

Molecular memory can be used to increase the memory capacity of hard disks
Researchers at the University of Jyväskylä have taken part in an international British-Finnish-Chinese collaboration where the first molecule capable of remembering the direction of a magnetic above liquid nitrogen temperatures has been prepared and characterized.

Memory transferred between snails
Memories can be transferred between organisms by extracting ribonucleic acid (RNA) from a trained animal and injecting it into an untrained animal, as demonstrated in a study of sea snails published in eNeuro.

Read More: Memory News and Memory Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.