This domain is found in signal transducer and activator of transcription A protein (STATa) present in Dictyostelium discoideum (dd). STATa is responsible for transcriptionally regulating cellular differentiation in Dictyostelium discoideum. ddSTATa is the only non-metazoan known to employ SH2 domain signaling. This domain adopts an Immunoglobulin-like fold [1].

1: Structure of an activated Dictyostelium STAT in its DNA-unbound form. Soler-Lopez M, Petosa C, Fukuzawa M, Ravelli R, Williams JG, Muller CW; Mol Cell. 2004;13:791-804. PMID:15053873