Protein region important for regulation of lipid metabolism in angiopoietin-like 3 (ANGPTL3): ANGPTL3 is cleaved and activated in vivo.
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.
Ono
Mitsuru
M
Biomedical Research Laboratories, Sankyo Co. Ltd., 2-58 Hiromachi 1-chome, Shinagawa-ku, Tokyo 140-8710, USA. mtrono@shina.sankyo.co.jp
Shimizugawa
Tetsuya
T
Shimamura
Mitsuru
M
Yoshida
Kenichi
K
Noji-Sakikawa
Chisa
C
Ando
Yosuke
Y
Koishi
Ryuta
R
Furukawa
Hidehiko
H
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
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