Functional domains in CsMRP4 revealed diverse characteristics of ABC transporters. There were “ABC transporter type 1, transmembrane domain” (InterProScan ID: IPR011527) in two regions, aa64–378 and aa831–1162. Two domains, MSD1 and MSD2, consisted of six transmembrane α-helices each. As intracellular NBDs that linked with the MSDs, “ABCC_MRP_domain1” (CDD ID: cd03250) for NBD1 and “ABCC_MRP_domain2” (CDD ID: cd03244) for NBD2 were found in the aa407–603 and aa1174–1394 regions, respectively. CsMRP4 had a single four-domain organization of MSD1-NBD1-MSD2-NBD2, which is common to all short forms of the ABCC subfamily, such as MRP4, 5, 8, 9, and CFTR .