title: Protein region important for regulation of lipid metabolism in angiopoietin-like 3 (ANGPTL3): ANGPTL3 is cleaved and activated in vivo.
abstract: Angiopoietin-like 3 (ANGPTL3) is a secreted protein that is mainly expressed in the liver and regulates lipid metabolism by inhibiting the lipolysis of triglyceriderich lipoproteins. Using deletion mutants of human ANGPTL3, we demonstrated that the N-terminal coiled-coil domain-containing fragment-(17-207) and not the C-terminal fibrinogen-like domain-containing fragment-(207-460) increased the plasma triglyceride levels in mice. We also found that the N-terminal region 17-165 was required to increase plasma triglyceride levels in mice and that a substitution of basic amino acid residues in the region 61-66 of the fragment showed no increase in the plasma triglyceride levels and no inhibition of lipolysis by lipoprotein lipase. In addition, when we analyzed ANGPTL3 in human plasma, we detected cleaved fragments of ANGPTL3. By analyzing recombinant ANGPTL3 in mouse plasma, we found that it was cleaved at two sites, Arg221 downward arrow Ala222 and Arg224 downward arrow Thr225, which are located in the linker region between the coiled-coil domain and the fibrinogen-like domain. Furthermore, a cleavage-resistant mutant of ANGPTL3 was determined to be less active than wild-type ANGPTL3 in increasing mouse plasma triglyceride levels but not in inhibiting lipoprotein lipase activity. These findings suggest that the cleavage of ANGPTL3 is important for the activation of ANGPTL3 in vivo.
authors.affiliation: Biomedical Research Laboratories, Sankyo Co. Ltd., 2-58 Hiromachi 1-chome, Shinagawa-ku, Tokyo 140-8710, USA. mtrono@shina.sankyo.co.jp
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ono
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shimizugawa
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Shimamura
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Chisa
authors.initials: C
authors.lastname: Noji-Sakikawa
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Ando
authors.forename: Ryuta
authors.initials: R
authors.lastname: Koishi
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Furukawa
mesh_terms: D000595:Amino Acid Sequence; D000091303:Angiopoietin-Like Protein 3; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; D000818:Animals; D001665:Binding Sites; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009154:Mutation; D010446:Peptide Fragments / Q000097:blood; D010449:Peptide Mapping; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins; D014280:Triglycerides / Q000097:blood
chemical_list: C479896:ANGPTL3 protein, human; D000091303:Angiopoietin-Like Protein 3; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; C404495:Angptl3 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014280:Triglycerides; D008071:Lipoprotein Lipase