title: Expression and functional analyses of novel mutations of ATP-binding cassette transporter-1 in Japanese patients with high-density lipoprotein deficiency.
abstract: ATP-binding cassette transporter-1 (ABCA1) gene is mutated in patients with familial high-density lipoprotein deficiency (FHD). In order to know the molecular basis for FHD, we characterized three different ABCA1 mutations associated with FHD (G1158A/A255T, C5946T/R1851X, and A5226G/N1611D) with respect to their expression in the passaged fibroblasts from the patients and in the cells transfected with the mutated cDNAs. Fibroblasts from the all patients showed markedly decreased cholesterol efflux to apolipoprotein (apo)-Al. In the fibroblasts homozygous for G1158A/A255T, the immunoreactive mass of ABCA1 could not be detected, even when stimulated by 9-cis-retinoic acid and 22-R-hydroxycholesterol. In the fibroblasts homozygous for C5946T/R1851X, ABCA1 mRNA was comparable. Because the mutant ABCA1 protein (R1851X) was predicted to lack the epitope for the antibody used, we transfected FLAG-tagged truncated mutant (R1851X/ABCA1-FLAG) cDNA into Cos-7 cells, showing that the mutant protein expression was markedly reduced. The expression of N1611D ABCA1 protein was comparable in both fibroblasts and overexpressing cells, although cholesterol efflux from the cells was markedly reduced. These data indicated that, in the three patients investigated, the abnormalities and dysfunction of ABCA1 occurred at the different levels, providing important information about the expression, regulation, and function of ABCA1.
authors.affiliation: Department of Internal Medicine and Molecular Science, Osaka University, Osaka, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nishida
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hirano
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tsukamoto
authors.forename: Makoto
authors.initials: M
authors.lastname: Nagano
authors.forename: Chiaki
authors.initials: C
authors.lastname: Ikegami
authors.forename: Kirsten
authors.initials: K
authors.lastname: Roomp
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Ishihara
authors.forename: Naoki
authors.initials: N
authors.lastname: Sakane
authors.forename: Zhongyan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Tsujii Ki
authors.forename: Akifumi
authors.initials: A
authors.lastname: Matsuyama
authors.forename: Tohru
authors.initials: T
authors.lastname: Ohama
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Matsuura
authors.forename: Masato
authors.initials: M
authors.lastname: Ishigami
authors.forename: Naohiko
authors.initials: N
authors.lastname: Sakai
authors.forename: Hisatoyo
authors.initials: H
authors.lastname: Hiraoka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hattori
authors.forename: Cheryl
authors.initials: C
authors.lastname: Wellington
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Susumu
authors.initials: S
authors.lastname: Misugi
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hayden
authors.forename: Toru
authors.initials: T
authors.lastname: Egashira
authors.forename: Shizuya
authors.initials: S
authors.lastname: Yamashita
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsuzawa
mesh_terms: D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics*; D000368:Aged; D000077556:Alitretinoin; D000818:Animals; D016632:Apolipoprotein A-I / Q000378:metabolism; D019556:COS Cells; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D017930:Genes, Reporter; D006720:Homozygote; D006801:Humans; D006888:Hydroxycholesterols / Q000494:pharmacology; D007564:Japan / Q000453:epidemiology; D008075:Lipoproteins, HDL / Q000172:deficiency*; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D013631:Tangier Disease / Q000453:epidemiology / Q000235:genetics*; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
chemical_list: C577836:ABCA1 protein, human; D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters; D016632:Apolipoprotein A-I; D018076:DNA, Complementary; D006888:Hydroxycholesterols; D008075:Lipoproteins, HDL; D012333:RNA, Messenger; C003585:22-hydroxycholesterol; D000077556:Alitretinoin; D014212:Tretinoin; D002784:Cholesterol