Fig. 3.

Example of an input submodule: assembly of influenza virus. Molecular level: molecular interactions (left; red arrows) between the viral RNA, the three polymerase proteins (PA, PB1, PB2) and the structural protein NP build the viral ribonucleoprotein-particle (vRNP). The glycoprotein HA (right) forms trimers, which associate with rafts in the plasma membrane. The coat protein M1 associates with membranes, where it binds weakly to the cytoplasmic tail of HA; these molecular interactions are illustrated by green arrows. Submodular level: oligomerization of M1 strengthens the weak interactions with HA and draws M1 to the viral budzone, preassembled viral envelopes. This submodular entity contains also the second viral glycoprotein neuraminidase (NA) and a few copies of the viral proton channel M2. Finally, the vRNPs bind to M1, a complete virus particle buds from the membrane and is released. The hallmarks of functional modules (grey lettering) are described in the text, 3.1, 3.2.