title: Characterization of ABCB9, an ATP binding cassette protein associated with lysosomes.
abstract: We have cloned full-length human and mouse cDNAs of ABCB9, which encodes a predicted multiple-spanning transmembrane domain and a nucleotide-binding domain with Walker motifs. It is therefore designated as a "half" ATP binding cassette (ABC) transporter. Northern analysis shows that the ABCB9 mRNA is expressed at a high level in testes and moderate levels in brain and spinal cord. A splice variant mRNA deleted in the last pair of predicted transmembrane segments was shown to be expressed in human tissues. Phylogenetic analysis indicates that ABCB9 is closely related to TAP1 and TAP2, two "half" ABC proteins found in endoplasmic reticulum. ABCB9 protein colocalized with the lysosomal markers, LAMP1 and LAMP2, in transfected cells. ABCB9 protein appears to be most highly expressed in the Sertoli cells of the seminiferous tubules in mouse and rat testes. These cells have high levels of phagocytosis and secretory activities. These findings pave the way for further investigation into the potential novel function of ABCB9 in lysosomes.
authors.affiliation: British Columbia Cancer Research Centre, British Columbia Cancer Agency, University of British Columbia, Vancouver, V5Z 1L3 Canada.
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: C L
authors.initials: CL
authors.lastname: Fisher
authors.forename: D
authors.initials: D
authors.lastname: Hui
authors.forename: S
authors.initials: S
authors.lastname: Childs
authors.forename: K
authors.initials: K
authors.lastname: Dorovini-Zis
authors.forename: V
authors.initials: V
authors.lastname: Ling
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: C412573:ABCB9 protein, human; D018528:ATP-Binding Cassette Transporters; C503300:Abcb9 protein, mouse; D017931:DNA Primers; D000255:Adenosine Triphosphate