Fig. 3

CircRNA-protein interactions. A (a) CircRNA binds to both proteins and strengthens their interaction. (b) CircRNA binds to protein A and reinforces its interaction with protein B, which does not directly bind to circRNA. (c) CircRNA binds to both proteins that originally combine with each other and then disrupts their interaction. B CircRNA blocks proteins from interacting with DNA, RNA or other proteins, thus compromising their original functions. C CircRNA recruits transcription factors, chromatin remodelers and DNA or histone modifying enzymes to the promoters and alters transcription (including activating and inhibiting). D CircRNA helps RBPs to combine with mRNA and stabilizes mRNA (indirectly promoting translation) or directly regulates translation (including promoting and inhibiting). E (a) Nuclear circRNA causes the nuclear retention of proteins. (b) Cytoplasmic or shuttling circRNA facilitates the nuclear import of proteins. (c) Cytoplasmic circRNA causes the cytoplasmic retention of proteins. (d) Nuclear or shuttling circRNA facilitates the nuclear export of proteins. (e-g) Furthermore, circRNAs can transport proteins to the nucleolus, mitochondria and membrane, respectively