Extra-Cellular Proteins are Key Elements of a Global Molecular Network Enmeshing the Whole Central Nervous System: Physiological and Pathological Implications

Proteins are endowed with the “Lego property”, i.e., the capability of steric fitting with other proteins to form high molecular weight complexes with emergent functions. These interactions may occur both as horizontal molecular networks at the plasma membrane level and as vertical molecular networks, i.e., towards the extra- and/or intracellular side of the cell. The present paper broadens this view by proposing the existence of three dimensional molecular networks, mainly made by proteins and carbohydrates, which might interact with each other at boundaries of compartments such as plasma membranes to form a “global molecular network” (GMN) that pervades the intra as well as the extra-cellular environment of the entire central nervous system. The GMN is a potentially plastic structure regulated through several means. For example, its extracellular part is under the remodeling action of the matrix metalloproteinases.