An inventory of the human ABC proteins

Currently 30 human ABC proteins are represented by full sequences in variou s databases, and this paper provides a brief overview of these proteins. AB C proteins are composed of transmembrane domains (TMDs), and nucleotide bin ding domains (NBDs, or ATP-binding cassettes, ABSs). The arrangement of the se domains, together with available membrane topology models of the family members, are presented. Based on their sequence similarity scores, the memb ers of the human ABC protein family can be grouped into eight subfamilies. At present the MDR/TAP, the ALD, the MRP/CFTR, the ABCl, the White, the RNA seL inhibitor, the ANSA, and the GCN20 subfamilies are identified. Mutation s of many human ABC proteins are known to be causative in inherited disease s, and a short description of the molecular pathology of these ABC gene-rel ated genetic diseases is also provided. (C) 1999 Elsevier Science B.V. All rights reserved.