Does post-translational modification influence chaperone-like activity of alpha-crystallin? I. Study on phosphorylation.

It is difficult to isolate derivatives of alpha-crystallin with only one type of post-translational modification, because this protein is subjected to several different types of modification. In the present study using bovine lens proteins, we isolated mono-phosphorylated alphaB-crystallin with no other post-translational modifications. Using this material, we demonstrated that mono-phosphorylation reduced the activity of alphaB-crystallin by approximately 30%. Our results confirmed that investigation of the correlation between chaperone-like activities of alpha-crystallin and post-translational modification is important to understand the mechanism of cataract formation.