Release of FUS into the extracellular space is regulated by its amino-terminal prion-like domain.

Fused in sarcoma (FUS) is a causative factor of amyotrophic lateral sclerosis (ALS) and is believed to propagate pathologically by transmission from cell to cell. However, the mechanism underlying FUS release from cells, which is a critical step for the propagation system, remains poorly understood. This study conducted an analysis of the release of human and mouse FUS from neurons, revealing that human FUS is significantly released into the media compared to its mouse counterpart. Further study using chimeric FUS proteins identified the amino-terminal region of human FUS as essential for its release. These findings indicate that human FUS is released directly from neurons and underscore the novel functional role of its amino-terminal region in this process.