Video Illuminates a Brain Cell
USC Dornsife’s Don Arnold was a lead researcher on a recent article in Cell Reports. Sarmad Al-Bassam, USC Dornsife Ph.D. student in molecular biology, was lead author of the article.
Using bioluminescent proteins from a jellyfish, a team of scientists has lit up the inside of a neuron, capturing video footage that shows the movement of proteins throughout the cell.
The video offers a rare peek at how proteins, the brain’s building blocks, are directed through neurons to renew its structure.
“Your brain is being disassembled and reassembled every day,” said Don Arnold, associate professor of molecular and computational biology in USC Dornsife, a lead researcher on the project and an author of an article about the study that appeared in Cell Reports on July 26.
“One week from today, your brain will be made up of completely different proteins than it is today,” Arnold said. “This video shows the process. We’ve known that it was happening, but now we can watch it happen.”
The imaging technique was used to cast new light on how proteins are directed to one of the two types of compartments inside the neuron: the axon or the dendrites.
The axon is the region of the cell responsible for transmitting electrical signals to other cells, while the dendrites receive signals from other cells.
“It’s been known for many decades that proteins are specifically targeted to one compartment or the other. However, we couldn’t understand how the targeting occurs until we could actually watch the proteins traveling to one compartment or to the other,” said Sarmad Al-Bassam, USC Dornsife Ph.D. student in molecular biology and lead author of the article.
Since the mid-1990s, scientists have been able to illuminate the proteins inside of cells, including neurons, by attaching a protein isolated from jellyfish — known as green fluorescent protein (GFP) — that fluoresces bright green when exposed to blue light.
Martin Chalfie of Columbia University, Roger Tsien of the University of California, San Diego, and Osamu Shimomura of Boston University were awarded the Nobel Prize in Chemistry in 2008 for the discovery and development of GFP.
The problem with studying the flow of illuminated proteins inside of neurons is that there are several different overlapping pathways within the cell, making it difficult to study the traffic through just one.
Al-Bassam and his colleagues solved this issue by developing a new technique that involves damming up a single pathway, which creates a backlog of transport vesicles (little bubbles that travel up and down neurons carrying membrane protein cargo) impregnated with the illuminated proteins. They then use a small-molecule drug to release the backlog all at once in a bright pulse.
“Our result was very surprising,” Arnold said. “We found that rather than being targeted specifically to the dendrites, vesicles carrying proteins initially enter both compartments, but then are stopped and prevented from moving beyond the initial segment of the axon.”
Al-Bassam and Arnold worked with USC Dornsife postdoctoral fellow Min Xu, as well as Thomas Wandless, professor at Stanford University.
The research was funded by National Institutes of Health grants NS-041963 and MH-086381.
Related News Items
- Chemists Dispel Long-held Notion September 26, 2014
- In Memoriam: Richard F. Thompson, 84 September 20, 2014
- Converging Science and Engineering September 18, 2014
- Welcome New Faculty September 16, 2014
- Close Look at Baldwin Hills September 16, 2014
- Heidelberg Steers the Ship September 15, 2014
- Chilton Wins Marine Award September 10, 2014
- Whale Mating: In the Hips September 10, 2014
- A Lexicon of the Brain September 2, 2014
- Discovery in Helium Droplets August 28, 2014
- Dutch Lessons on GeoDesign July 31, 2014
- Where Earth and Life Sciences Merge July 24, 2014
- Manahan Named Honorary Fellow July 22, 2014
- World’s Most Influential Scientists July 17, 2014
- Kay Lab Creates First Vast Library of Master Genetic Switches in Plants July 17, 2014
- Helping Us Breathe Easier July 14, 2014
- Alumnus Goes Full Speed Ahead July 10, 2014
- Bonahon Named Simons Fellow July 8, 2014
- Arctic Fox, Woolly Rhino and Three-toed Horse June 17, 2014
- Hats Off to Dr. Research June 12, 2014