Carries out a dual function: signal transduction and activation of transcription (By similarity). By regulating the up-regulation in the epidermis of antimicrobial peptides nlp-29, plays a role in resistance to fungal infection and in the response to physical wounding and phorbol ester PMA treatment (PubMed:22470487). Translocated into the nucleus in response to phosphorylation. Belongs to the transcription factor STAT family. Intron retention.