Pre-assembled complexes and allosteric effects: parallels between eukaryotic phosphorylation cascades and membrane fusion during herpesviral entry

Unlike most enveloped viruses, <i>Herpesviridae</i> distribute cell entry functions across several viral envelope proteins. The prevailing model posits that, upon interaction with the target cell, the activating signal is transmitted from the receptor-binding to the fusion-mediating component in a signaling cascade that involves sequential interactions. However, herpesvirus entry proteins may form complexes throughout fusion. Here, we propose that-by analogy with certain eukaryotic signaling cascades-transmission of the activating signal involves pre-assembled complexes and allosteric effects.