Tyrosine protein kinase JAK1 (JAK1) binds Interleukin-20 receptor subunit alpha (IL20RA). JAK1 coimmunoprecipitates with several class II receptor complexes including Interferon gamma receptor 1 (IFNGR1), Interferon alpha/beta receptor 2 (IFNAR2), Interferon lambda receptor 1 (IFNLR1), Interleukin-10 receptor subunit alpha (IL10RA), Interleukin-22 receptor subunit alpha 1 (IL22RA1) and Interleukin-20 receptor subunit alpha (IL20RA), leading to the suggestion that Class II receptors may have a common sequence motif for JAK recognition (Ferrao et al. 2016). This is a black box event because JAK1 binding to IL20RA is inferred from binding to related receptors and subsequent JAK/STAT signaling events (Ferrao et al 2016, Hann et al. 2006, Murakami et al. 1991).