Post-Translational Modifications of Eye Lens Crystallins: Crosslinking, Phosphorylation and Deamidation

Our knowledge of the structural and functional effects of post-translational modifications of proteins is still fragmentary. It is in general implicitly assumed that such modifications must have important biological roles, in the regulation of enzyme activities, protein interactions or turnover. Although such functions seem plausible in many instances, definite proof is often difficult to provide, and in fact it cannot be excluded that certain modifications are functionally unimportant and just occur as innoxious by-products of the intracellular metabolism. For a better understanding of the meaning of post-translational modifications it is important to analyze and compare their occurrence and features in different proteins and cell types. This contribution reports some recent findings on post-translational modifications of eye lens proteins.