• Identified MAPK1 as a novel interacting partner of Eimeria acervulina serine protease inhibitor (Ea-SERPIN) using yeast two-hybrid screening.
• Ea-SERPIN shows high homology (87%) with E. maxima SERPIN and 43% with Toxoplasma gondii SERPIN, suggesting conserved functions.
• The interaction between Ea-SERPIN and host MAPK1 may play a role in the invasion mechanism of E. acervulina, offering a potential target for coccidiosis control.
• This preliminary study provides a foundation for further functional characterization of Ea-SERPIN in host-parasite interactions.