Validation of Petri net apoptosis models using P-invariant analysis

Apoptosis, the genetically programmed cell death, is essential to the physiology of most metazoan species, including the human. It involves a complex signal transduction pathway for the initiating of apoptotic signals, and the ultimate execution of apoptosis. This paper demonstrates the modeling of both the extrinsic and intrinsic human apoptotic pathways using Petri nets. This model is then validated using P-invariant analysis. Validation is required to systematically check the model and increase our confidence in it. While Heiner et al. has shown how T-invariants can be used for this purpose, this paper will explore the use of P-invariant analysis and ultimately establish it as an alternative way of performing validation for our qualitative model.