4IF8

Structure Of Vaspin

Summary for 4IF8

• Entry DOI: 10.2210/pdb4if8/pdb
• Descriptor: Serpin A12, SULFATE ION (3 entities in total)
• Functional Keywords: serpin, serine protease inhibitor, kallikrein 7, hydrolase inhibitor
• Biological source: Homo sapiens (human)
• Cellular location: Secreted (Potential): Q8IW75
• Total number of polymer chains: 2
• Total formula weight: 95379.85

Authors

Kuettner, E.B.,Strater, N.,Heiker, J.T.,Kloting, N.,Kovacs, P.,Schultz, S.,Kern, M.,Stumvoll, M.,Bluher, M.,Beck-Sickinger, A.G. (deposition date: 2012-12-14, release date: 2013-02-13, Last modification date: 2023-11-08)

Primary citation

Heiker, J.T.,Kloting, N.,Kovacs, P.,Kuettner, E.B.,Strater, N.,Schultz, S.,Kern, M.,Stumvoll, M.,Bluher, M.,Beck-Sickinger, A.G.
Vaspin inhibits kallikrein 7 by serpin mechanism
Cell.Mol.Life Sci., 70:2569-2583, 2013

PubMed Abstract: The molecular target of the adipokine vaspin (visceral adipose tissue-derived serpin; serpinA12) and its mode of action are unknown. Here, we provide the vaspin crystal structure and identify human kallikrein 7 (hK7) as a first protease target of vaspin inhibited by classical serpin mechanism with high specificity in vitro. We detect vaspin-hK7 complexes in human plasma and find co-expression of both proteins in murine pancreatic β-cells. We further demonstrate that hK7 cleaves human insulin in the A- and B-chain. Vaspin treatment of isolated pancreatic islets leads to increased insulin concentration in the media upon glucose stimulation without influencing insulin secretion. By application of vaspin and generated inactive mutants, we find the significantly improved glucose tolerance in C57BL/6NTac and db/db mice treated with recombinant vaspin fully dependent on the vaspin serpin activity and not related to vaspin-mediated changes in insulin sensitivity as determined by euglycemic-hyperinsulinemic clamp studies. Improved glucose metabolism could be mediated by increased insulin plasma concentrations 150 min after a glucose challenge in db/db mice, supporting the hypothesis that vaspin may inhibit insulin degradation by hK7 in the circulation. In conclusion, we demonstrate the inhibitory serpin nature and the first protease target of the adipose tissue-derived serpin vaspin, and our findings suggest hK7 inhibition by vaspin as an underlying physiological mechanism for its compensatory actions on obesity-induced insulin resistance.

PubMed: 23370777
DOI: 10.1007/s00018-013-1258-8

Experimental method

X-RAY DIFFRACTION (2.08 Å)