Boffins: Microgravity impacts cell repair systems in proteins

Yeast-based study illuminates understanding of how 'nauts physiology may change in space

Cellular repair systems seem to respond to microgravity, scientists have found, leading to the hope they can better understand the effects of space flight on the human body.

A research team at Oklahoma State University focused on SUMO — small proteins which attach to and modify other proteins in cells — to see how they interacted with yeast cells under normal gravity, and under space’s microgravity simulated using rotating wall vessels.

“Under normal gravity conditions, SUMO is known to respond to stress and to play a critical role in many cellular processes, including DNA damage repair, cytoskeleton regulation, cellular division and protein turnover,” said research team leader Rita Miller, a professor of biochemistry and molecular biology at Oklahoma State University in Stillwater.

“This is the first time that SUMO has been shown to have a role in the cell’s response to microgravity,” Miller added.

Jeremy Sabo, a graduate student in Miller’s laboratory, analyzed cells that had undergone six cellular divisions in either normal Earth gravity or microgravity simulated using a specialized cell culture vessel developed by NASA.

The researchers found 37 proteins that physically interacted with SUMO. Interactions between SUMO and the proteins changed by more than 50 per cent in these cases. The named proteins include those that are important for DNA damage repair, a finding which may prove important given the damage radiation can cause to human cells in space. Other proteins were involved in energy and protein production as well as maintaining cell shape, cell division and protein trafficking inside cells.

The paper was published and presented at Discover BMB, the annual meeting of the American Society for Biochemistry and Molecular Biology.

The Society said: “These differentially abundant proteins are involved in DNA damage repair, and cellular division regulation… Together, this data suggests that SUMO is a key factor in cellular adaptation to microgravity stress and provides insights at the cellular level about how cells manage the stress of microgravity.”

“Our work may also lead to a better understanding of how it controls various signaling cascades in response to simulated microgravity,” said Miller. ®