Although the mechanisms of action of a number of Axon Ligands™ remain ambiguous, they can significantly affect biological processes of various kinds. While interacting with regulator proteins in this section, they may have therapeutic applications as their target proteins play a role in the regulation and/or facilitation of processes within the cell, without having enzymatic or transporting properties by themselves. Additionally, their mode of action may not have been elucidated in great detail, yet evidence has been found for a certain role in, for example: signaling pathways, apoptosis, or stem cell differentiation.Calmodulin (CaM) is a ubiquitous regulatory protein that communicates the presence of calcium to its molecular targets and correspondingly modulates their function. This key signaling protein is important for controlling the activity of hundreds of membrane channels and transporters. CaM contains two globular domains each containing a pair of helix-loop-helix Ca2+-binding sites (EF-hands). Upon Ca2+ binding, conformational transitions in calmodulin are induced that changes its affinity to target proteins. One example of the proteins function being regulated by CaM is the family of auqaporins (AQPs): water channels that facilitate the flux of water molecules across membranes. Regulation of the water permeability by CaM is achieved through a Ca2+-dependent interaction between Ca2+-CaM and the cytoplasmic C-terminal domain of the AQP.Avridine (Axon 2099), for example, is a lipoidal amine with interferon-inducing and adjuvant properties specifically related to Newcastle disease. What’s more, although avridine is a synthetic non-immunogenic adjuvant, it is also known to induce arthritis in rats in a predictable and T-cell dependent way. However, the mechanism of action by which this Avridine Induced Arthritis (AvIA) is triggered, or acts as adjuvant of the Newcastle disease antigen has not been elucidated in detail.