Research progress of extracrystalline functions of βB2-crystallin

βB2-crystallin is the main structural protein in the vertebrate lens. In addition to lens, recent studies have found that βB2-crystallin also plays a very prominent and even unique role outside the lens. βB2-crystallin is unexpectedly highly expressed in retina, brain, testis, and ovary. It can not only promote the regeneration of optic nerve axons, protect the injured optic nerve, but also affect sensory motor gating and hippocampal function, and even plays an important role in reproductive function, or even related to fetal abortion. In addition, new studies have shown that βB2-crystallin is also related to the occurrence and development of a variety of tumors. This paper reviews the function and research progress of βB2-crystallin function outside the lens.