Figure 1.

RBPs regulatory interplay modes. The figure shows the different patterns of regulatory interaction observed between RNA-binding proteins. We use a hypothetical mRNA 3′UTR as the interaction substrate to illustrate these mechanisms. (A) Describes the cooperative interplay mode. We have proximal cooperative binding (up) when two RBPs physically interact through nearby binding sites (or distant sites brought in proximity by the RNA secondary structure conformation), thus shaping their action through this interaction. RBPs can also cooperate through distant binding sites and without interacting directly (down), exerting their synergistic activity independently from one another. (B) Represents the competitive interplay mode. This pattern consists of two RBPs (RBP1 and RBP2), contending for binding to one or more overlapping binding sites on an RNA species. This competition results in a balance of RBP1 and RBP2 bound to these molecules, which determines the outcome of the regulation. (C) Describes the mutual interplay mode. Here, two RBPs (RBP1 and RBP2) can control the expression of one another to constrain and fine-tune the outcome of the regulation of their target RNAs. This mechanism can be heterogeneous (up), with RBP2 binding to RBP1 mRNA (or vice-versa) or autogenous (down), where an RBP binds to its cognate mRNA.