Rigidity and flexibility in protein-protein interaction networks: a case   study on neuromuscular disorders
  Mutations in proteins can have deleterious effects on a protein's stability and function, which ultimately causes particular diseases. Genetically inherited muscular dystrophies (MDs) include several genetic diseases, which cause increasing weakness in muscles and disability to perform muscular functions progressively. Different types of mutations in the gene coding translates into defunct proteins cause different neuro-muscular diseases. Defunct protein interactions in human proteome may cause a stress to its neighboring proteins and its modules. We therefore aimed to understand the effects of mutated proteins on interacting partners in different muscular dystrophies utilizing network biology to understand system properties of these MDs subnetworks .We investigated rigidity and flexibility of protein-protein interaction subnetworks associated with causative mutated genes showing high mean interference values in muscular dystrophy. Rigid component related to EEF1A1 subnetwork and members of 14.3.3 protein family formed the core of network showed involvement in molecular function related to protein domain specific binding. CACNA1S and CALM1 showing functionality related to Voltage-dependent calcium channel demonstrated highest flexibility. The interconnected subnets of proteins corresponding to known causative genes having large genetic variants are shared in different muscular dystrophies inferred towards comorbidity in diseases. The studies demonstrates core network of MDs as highly rigid, constituting of large intermodular edges and interconnected hub nodes suggesting high information transfer flow. The core skeleton of the network is organized in protein specific domain binding. This suggests neuro-muscular disorders may initiate due to interruption in molecular function related with the core and its aggression may depend on the tolerance level of the networks. 
Ankush Sharma, Maria Brigida Ferraro, Francesco Maiorano, Francesca   Del Vecchio Blanco and Mario Rosario Guarracino
q-bio.MN