title: Roles of CTPL/Sfxn3 and Sfxn family members in pancreatic islet.
abstract: Pancreatic AR42J cells have the feature of pluripotency of the precursor cells of the gut endoderm. Betacellulin (BTC) and activin A (Act) convert them into insulin-secreting cells. Using mRNA differential display techniques, we have identified a novel mitochondrial transporter, which is highly expressed during the course of differentiation, and have designated it citrate transporter protein-like protein (CTPL). Recently sideroflexin 1 (Sfxn1) was shown to be a susceptible gene of flexed-tail (f/f) mice, and CTPL has turned out to be a rat orthologous protein of Sfxn3, a member of sideroflexin family. CTPL/Sfxn3 was targeted to mitochondrial membrane like Sfxn1. The expression levels of CTPL/Sfxn3, Sfxn2, and Sfxn5 were upregulated in the early phase of differentiation into insulin-secreting cells but the expression levels of Sfxn1 and Sfxn3 did not change. All Sfxn family members were expressed in rat pancreatic islet. The expression levels of CTPL/Sfxn3, Sfxn2, and Sfxn5 were also upregulated in islets of streptozotocin-induced diabetic rats compared to normal rats. The downregulation of CTPL/Sfxn3 in a rat insulinoma cell line, INS-1, with the antisense oligonucleotide did not affect the insulin secretion. Taken together, CTPL/Sfxn3 and some other family members might be important in the differentiation of pancreatic beta-cells as a channel or a carrier molecule and be related to the regeneration of pancreatic endocrine cells.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Yoshikumi
authors.forename: Hirosato
authors.initials: H
authors.lastname: Mashima
authors.forename: Namiki
authors.initials: N
authors.lastname: Ueda
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohno
authors.forename: Junko
authors.initials: J
authors.lastname: Suzuki
authors.forename: Shigeyasu
authors.initials: S
authors.lastname: Tanaka
authors.forename: Michio
authors.initials: M
authors.lastname: Hayashi
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sekine
authors.forename: Hirohide
authors.initials: H
authors.lastname: Ohnishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yasuda
authors.forename: Taroh
authors.initials: T
authors.lastname: Iiri
authors.forename: Masao
authors.initials: M
authors.lastname: Omata
authors.forename: Toshiro
authors.initials: T
authors.lastname: Fujita
authors.forename: Itaru
authors.initials: I
authors.lastname: Kojima
mesh_terms: D000818:Animals; D027682:Cation Transport Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D007328:Insulin / Q000494:pharmacology; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats
chemical_list: D027682:Cation Transport Proteins; D007328:Insulin; D012333:RNA, Messenger; C506522:Sfxn3 protein, mouse; C506521:Sfxn3 protein, rat