p38 MAPK orchestrates cross-tissue potassium homeostasis for survival

Potassium is vital for life, yet how potassium homeostasis is maintained at the tissue or organismal level under dietary scarcity remains poorly understood. Stress-activated signaling pathway p38 MAPK is implicated in immune response and aging, but its specific role in low potassium response is unclear. Here we show that a specific p38 MAPK-ATF-7 pathway orchestrates cross-tissue potassium homeostasis in Caenorhabditis elegans. It drives transcriptional upregulation of a crucial P-type ATPase pump CATP-3 specifically in the hypodermis, a process that integrates cell-autonomous mechanisms with non-autonomous ASI neuronal signals, thereby enhancing organismal survival during potassium deficiency. Notably, this regulation is distinct from canonical osmotic stress responses, revealing a specialized and conserved survival strategy. Analogous p38-mediated control of P-type ATPases occurs in yeast and mammalian cells, suggesting broad relevance. Our findings redefine potassium regulation as a cross-tissue process linked to lifespan, stress signaling, and innate immunity with potential implications for aging and age-related diseases.