A new study finds that the proteasome might have more functions than just breaking down proteins in cells. Researchers have found that the proteasome is even playing a role in regulating the packing of DNA in the nucleus. The work comes from Korea Institute of Science and Technology and will be published in the Journal of Biological Chemistry on Friday, October 13.
In experiments using yeast cells, researchers found that the proteasome could induce heterochromatin to form in some parts of the genome but stop it from spreading to other regions. However, this was not done through proteolysis, which still puzzles the researchers.
"[The proteasome] can exert force on proteins and translocate, tilt, bend them," said Hogyu David Seo, a graduate student in Daeyoup Lee, Ph.D.'s lab. "So I believe the proteasome physically modulates proteins that act as a shield for heterochromatin. That's how I think it might work."
How heterochromatin forms and spreads is an interesting topic in epigenetics because the changes are inheritable from generation to generation.
"[The proteasome] may have some effect on epigenetic programming inheritance because it affects the spreading of heterochromatin," Seo said. "I'm not really sure how it might work because there are so many ways that it could act, but I'm sure that it may exert some effects on epigenetic programming."
Currently, the team is focusing on how the proteasome regulates heterochromatin in other organisms. Their work on the proteasome and its effects on heterochromatin could help develop therapeutics for a variety of diseases, such as cancer.