title: Molecular identification and characterization of a novel nuclear protein whose expression is up-regulated in insulin-resistant animals.
abstract: Energy metabolism is the most fundamental capacity for mammals, impairment of which causes a variety of diseases such as type 2 diabetes and insulin resistance. Here, we identified a novel gene, termed diabetes-related ankyrin repeat protein (DARP) that is up-regulated in the heart of KKA(y) mouse, a type 2 diabetes and insulin resistance model animal. DARP contains putative nuclear localization signals and four tandem ankyrin-like repeats. Its expression is restricted in heart, skeletal muscle, and brown adipose. Western blot analysis and immunocytochemistry of DARP-transfected Chinese hamster ovary (CHO) and COS-7 cells reveal that DARP is a nuclear protein. When DARP is expressed in CHO cells, [1-(14)C]palmitate uptake is significantly decreased, whereas the palmitate oxidation does not show significant change. Furthermore, DARP expression is altered by the change of energy supply induced by excess fatty acid treatment of skeletal myotube in vitro and fasting treatment of C57 mouse in vivo. We confirmed that DARP expression is also altered in Zucker fatty rat, another insulin resistance model animal. Taken together, these data suggest that DARP is a novel nuclear protein potentially involved in the energy metabolism. Detailed analysis of DARP may provide new insights in the energy metabolism.
authors.affiliation: Division of Cardiovascular and Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ikeda
authors.forename: Noriaki
authors.initials: N
authors.lastname: Emoto
authors.forename: Masafumi
authors.initials: M
authors.lastname: Matsuo
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yokoyama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D017931:DNA Primers; D004734:Energy Metabolism; D005227:Fatty Acids / Q000378:metabolism; D007150:Immunohistochemistry; D007333:Insulin Resistance; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009124:Muscle Proteins; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid; D015854:Up-Regulation
chemical_list: C472289:ANKRD23 protein, human; C472288:DARP protein, mouse; D017931:DNA Primers; D005227:Fatty Acids; D009124:Muscle Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger