Signal transducer and activator of transcription 1 alpha/beta (STAT1) and Signal transducer and activator of transcription 3 (STAT3) are believed to be phosphorylated after binding the Interleukin-24 (IL24) receptor complex (Parrish Novak et al. 1998, Andoh et al. 2009, Wang et al. 2002). This complex consists of IL24 ligand, phosphorylated Interleukin-20 receptor subunit alpha (IL20RA), phosphorylated Tyrosine-protein kinase JAK1 (JAK1), Interleukin-20 receptor subunit beta (IL20RB) and STAT1 or STAT3 .
This is a black box event because STAT binding is inferred to precede STAT phosphorylation.