This protein is a part of the Major Facilitator Superfamily (pfam07690). Member of this family are found in a number of proteobacterial genomes, but only in the context of having genes for 4-hydroxyphenylacetate (4-HPA) degradation. The protein is characterized by Prieto, et al. ( as 4-hydroxyphenylacetate permease in E. coli, where 3-HPA and 3,4-dihydroxyphenylacetate are shown to competitively inhibit 4-HPA transport and therefore also interact specificially.