The seminal fluid protein SFP-1 regulates mated hermaphrodite aging and fat metabolism in C. elegans.

Across the evolutionary spectrum, sexual interactions can significantly influence the physiology and somatic aging in various species. In Caenorhabditis, male pheromones, sperm, and seminal fluid shorten the lifespan of hermaphrodites through different mechanisms. However, the specific male seminal fluid proteins responsible for this effect remain unidentified. Here, we find that several of the previously observed physiological changes in mated hermaphrodites require a newly-identified seminal fluid protein. SFP-1 is packaged into secretory vesicles via the phospholipid scramblases ANOH-1 and ANOH-2 in male seminal vesicles, and after mating taken up by intestinal cells via endocytosis. Within these intestinal cells, the NTF2-like domain of SFP-1 interacts with and activates the transcription factor SKN-1, which induces post-mating somatic fat depletion and lifespan reduction. Together, these results define how a male seminal-fluid protein can trigger mating-induced physiological changes in sexual interactions.