ABCG4 may mediate cholesterol efflux

Human ABCG4 shows sequence homology to the Drosophila white gene, the product of which must dimerise to become functionally active. ABCG4 is closely related to ABCG1 with 74% identity and is thus thought to play a role in the efflux of excess cholesterol (Engel et al. 2001). Northern Blot analysis shows that ABCG4 is expressed specifically in brain and the eye (Oldfield et al. 2002).人类ABCG4基因序列与果蝇白基因具有序列同源性，其产物必须形成二聚体才能发挥功能活性。ABCG4与ABCG1密切相关，两者同源性达到74%，因此被认为在过量胆固醇的排泄中扮演重要角色（Engel等，2001年）。Northern Blot分析表明，ABCG4在脑部和眼睛中特异性表达（Oldfield等，2002年）。