Surprising Role for Protein Involved in Cell Death

C. elegans
Many of the key players in regulating apoptosis were discovered in C. elegans. This tiny roundworm has more than 19,000 genes, and a vast number of them are very similar to genes in other organisms, including people. Credit: Ewa M. Davison.

Our cells come equipped with a self-destruct mechanism that’s activated during apoptosis, a carefully controlled process by which the body rids itself of unneeded or potentially harmful cells. Scientists have long known that a protein called PSR-1 helps clean up the cellular remains. Now they’ve found that PSR-1 also can repair broken nerve fibers.

Ding Xue of the University of Colorado, Boulder, and others made the finding in the tiny roundworm C. elegans, which scientists have used to study apoptosis and identify many of the genes that regulate the process. While apoptotic cells sent “eat me” signals to PSR-1, injured nerve cells sent “save me” signals to the protein. These SOS signals helped reconnect the broken nerve fibers, called axons, that would otherwise degenerate after an injury.

Knowing more about PSR-1’s restorative response could aid efforts to develop therapeutic drugs for various disease- or injury-related central nervous system conditions. “Whether human PSR has the capacity to repair injured axons is still unknown,” Xue says in a news release about the study. “But I think our new research findings will spur a number of research groups to chase this question.”

This work was funded in part by NIH grant R01GM088241.