Formation and Cooperative Behaviour of Protein Complexes on the Cell Membrane With the aim of providing a deeper insight into possible mechanisms of biological self organization this thesis presents new approaches to describe the process of self assembly and the impact of spatial organization on the function of membrane proteins from a statistical physics point of view. It focuses on three important scenarios: the assembly of membrane proteins the collective response of mechanosensitive channels and the function of the twin arginine translocation (Tat) system. Using methods from equilibrium and non equilibrium statistical mechanics general conclusions were drawn tha With the aim of providing a deeper insight into possible mechanisms of biological self organization this thesis presents new approaches to describe the process of self assembly and the impact of spatial organization on the function of membrane proteins from a statistical physics point of view. It focuses on three important scenarios: the assembly of membrane proteins the collective response of mechanosensitive channels and the function of the twin arginine translocation (Tat) system. Using methods from equilibrium and non equilibrium statistical mechanics general conclusions were drawn that demonstrate the importance of the protein protein interactions. Namely in the first part a general aggregation dynamics model is formulated and used to show that fragmentation crucially affects the efficiency of the self assembly process of proteins. In the second part by mapping the membrane mediated forces into a simplified many body system the dynamic and equilibrium behaviour of interacting mechanosensitive channels is derived showing that protein agglomeration strongly impacts its desired function. The final part develops a model that incorporates both the agglomeration and transport function of the Tat system thereby providing a comprehensive description of this self organizing process