Interleukin-23 receptor signaling leads to Signal transducer and activator of transcription 3/Signal transducer and activator of transcription 4 (STAT3:STAT4) heterodimer activation in addition to the activation of STAT3 homodimers. Although Interleukin 23 activates the same spectrum of JAK/STAT molecules as interleukin 12, Interleukin-23 activates STAT4 to a lesser extent (Oppmann et al. 2000, Parham et al. 2012). The STAT3:STAT4 heterodimer translocates to the nucleus.
This reaction is presented as a black box event because the exact mechanism of translocation to the nucleus is unknown.