Fig. 5
Proposed deregulation of type I IFN signalling pathway by AFB1. The type I IFN signalling pathway begins when ligand such as IFN-α/β molecules binds to IFNAR1/2 which are associated with Tyk2 and JAK1 respectively. The interaction between IFN-α/β and the receptor results in phosphorylation and activation of Tyk2 and JAK1. The activated JAKs in turn recruit and phosphorylate STAT1 and STAT2 on tyrosine 701 (727 as well) and 690 respectively. The phosphorylated and activated STAT1 and STAT2 come together and form heterodimer. The dimerized STAT1 and STAT2 recruits IRF-9 and form the ISGF-3 transcription factor complex. The ISGF-3 enters the nucleus and interacts with ISRE which results in the transcription of IFN-inducible genes that switch on the anti-cancer as well as the anti-viral defense system. The current study has demonstrated that AFB1 suppresses or inhibits the mRNA expression levels of JAK1, STAT1 and OAS3 (indicated by red font and straight lines crossed at one end). In addition, protein expression level of STAT1 was also demonstrated to be inhibited by AFB1