The Prediction And Location Of Nuclear Export Signals In αB-crystallin

αB-crystallin (protein product of CRYAB ) is a kind of structural protein in the lens , form the lens with other components proteins. Blindiness is a kind of important human diseases. There are at least one third of congenital cataract cases which were caused by mutations of cataract genes . As the product of CRYAB,αB-crystallin is initially known as major lens structural proteins that plays an essential role in maintaining the transparency of lens.αB-crystallin is a member of the heat shock protein family, found to act as molecular chaperones and prevent the aggregation of other proteins in the lens cell, to maintain the functions of these proteins;αB-crystallin displays autokinase activity, it could be activated by heat shock, radiation, hypoxia and some drugs;αB could interact with various apoptotic regulators to resist apoptosis. Recent study showed it might perform as an type of oncogene; It have great significance to study the function of the gene mutation for the elucidation in the diseases related to the molecular pathology of CRYAB.In the complex process of physiological function ofαB-crystallin, the protein can be dynamic access to nuclear and output. We suppose that in the nuclear transit process, CRYAB relies on its inherent nuclear export signal. On the other hand, other nuclear transit receptor proteins are involved to collaborate with CRYAB for its export. We performed bioinformatics search on CRYAB sequnce, results disclosed that CRYAB's amino acid sequence from 68 to 81 may have the characteristics of nuclear export signal.Our study focused on the subcellular localization of CRYAB in HLE cell lines through the mediation of GFP and found that CRYAB was distributed uniformly in cytoplasm under fluorescence microscope. We constructed a CRYAB mutant of which the mutation was a part of nuclear export signal. Using GFP-mediated direct fluorescence localization method, we found that mutant CRYAB localized in the nucleus, indicating there were obstacles to shift. Also, under the effect of the nuclear export inhibitor LMB, corresponding changes of CRYAB location also occurred. It showed the 68-81 amino acids of CRYAB played a decisive role in nuclear export signal. We speculate it a functional export signal sequence.Through the research ofαB-crystallin in nuclear export mechanism, to provide the basic function for a more in-depth system to explain the molecular mechanisms ofαB-crystallin in diseases...