Proteins are the body’s workhorses. They provide for the structure, function, and regulation of the body’s organs by performing crucial tasks such as transporting molecules to and from cells, relaying chemical messages, and forming antibodies. However, not all proteins perform the same function; different proteins have different shapes that allow different functions. A protein’s unique shape is determined by the interactions between its molecular sub-units called amino acids. If a protein is damaged in such a way that its amino acids don’t interact correctly, its shape changes, rendering it incapable of performing tasks properly. These damaged or “misfolded” proteins aggregate in brain cells, which can cause neurodegenerative diseases such as Alzheimer’s, Huntington’s, and Parkinson’s.
Image Source: Ed Reschke
Healthy cells have a protein complex called proteasome that regulates the amount of misfolded proteins by breaking them down so that their amino acids can be re-used in creating new proteins. Through the use of electron cryotomography, researchers at the Max Planck Institute of Biochemistry have recently devised a method to view individual proteasomes in neurons cultured from the brains of healthy rats. Electron cryotomography involves reducing the temperature of a cell to -170ºC in order to take 2-D pictures at many different angles and combining them into a 3-D image. This technique produces images at resolutions of around 2 to 3 nanometers, allowing researchers to analyze both the structure and activity of proteasomes in neurons. Their observations showed that only around 20% of a specific proteasome called 26S proteasome found in neurons are actively degrading proteins. The significance of the unused protein complex has yet to be discovered. Subsequent experiments will analyze how the behavior of 26S proteasome changes in cells due to neuro-degenerative diseases.
The research paper can be found here.
Feature Image Source: icy twig by Cyndy Sims Parr
