Molecular network involving Rac1, Erk1/2 and HBA. The figure illustrates possible relationships among Rac1, Erk1/2 and HBA proteins, as revealed by the results of Protein Interaction Network analysis performed by the MetaCore program (Version 6.14), using Rac1 and HBA as root proteins (blue circles). The orange objects represent protein kinases; among them those with phosphatase activities are indicated by a hallow dot in the object. The direction of arrow-headed cyan lines indicates outgoing interaction. Accordingly, a possible forward going, regulatory relationship among Rac1, Erk1/2 and HBA is demonstrated.