The Interplay Between Antioxidant and Chaperone Functions of α-Crystallin.

α-Crystallin, the predominant protein of the eye lens, possesses molecular chaperone activity and antioxidative properties, both of which are essential for maintaining lens transparency. Its chaperone function prevents the formation of light-scattering protein aggregates, while its antioxidative activity mitigates oxidative stress through both direct and indirect mechanisms. However, with aging, α-crystallin undergoes cumulative post-translational modifications and oxidative damage, leading to protein crosslinking and a decline in chaperone efficacy. Notably, α-crystallin exhibits free radical-scavenging activity comparable to that of serum albumin, a well-characterized antioxidant protein. In addition, its ability to bind redox-active metal ions and convert them into redox-inactive forms significantly reduces reactive oxygen species (ROS) generation in vivo. α-Crystallin also interacts with key proteins and signaling pathways involved in oxidative stress responses, further enhancing its multifunctional protective role. This review summarizes current evidence on the antioxidative properties of α-crystallin and their relationship to its chaperone function, highlighting its importance in lens homeostasis and age-related cataract formation.