Adiponectin multimerization is dependent on conserved lysines in the collagenous domain: Evidence for regulation of multimerization by alterations in posttranslational modifications

Richards, Ayanthi A., Stephens, Tim, Charlton, Hayley K., Jones, Alun, Macdonald, Graeme A., Prins, Johannes B. and Whitehead, Jonathan P. (2006) Adiponectin multimerization is dependent on conserved lysines in the collagenous domain: Evidence for regulation of multimerization by alterations in posttranslational modifications. Molecular Endocrinology, 20 7: 1673-1687. doi:10.1210/me.2005-0390


Author Richards, Ayanthi A.
Stephens, Tim
Charlton, Hayley K.
Jones, Alun
Macdonald, Graeme A.
Prins, Johannes B.
Whitehead, Jonathan P.
Title Adiponectin multimerization is dependent on conserved lysines in the collagenous domain: Evidence for regulation of multimerization by alterations in posttranslational modifications
Journal name Molecular Endocrinology   Check publisher's open access policy
ISSN 0888-8809
Publication date 2006-01-01
Year available 2006
Sub-type Article (original research)
DOI 10.1210/me.2005-0390
Open Access Status DOI
Volume 20
Issue 7
Start page 1673
End page 1687
Total pages 15
Editor J. Cidlowski
M. Haworth
Place of publication USA
Publisher The Endocrine Society
Language eng
Subject C1
321004 Endocrinology
730105 Endocrine organs and diseases (incl. diabetes)
Abstract Adiponectin is a secreted, multimeric protein with insulin-sensitizing, antiatherogenic, and antiinflammatory properties. Serum adiponectin consists of trimer, hexamer, and larger high-molecular-weight (HMW) multimers, and these HMW multimers appear to be the more bioactive forms. Multimer composition of adiponectin appears to be regulated; however, the molecular mechanisms involved are unknown. We hypothesize that regulation of adiponectin multimerization and secretion occurs via changes in posttranslational modifications (PTMs). Although a structural role for intertrimer disulfide bonds in the formation of hexamers and HMW multimers is established, the role of other PTMs is unknown. PTMs identified in murine and bovine adiponectin include hydroxylation of multiple conserved proline and lysine residues and glycosylation of hydroxylysines. By mass spectrometry, we confirmed the presence of these PTMs in human adiponectin and identified three additional hydroxylations on Pro71, Pro76, and Pro95. We also investigated the role of the five modified lysines in multimer formation and secretion of recombinant human adiponectin expressed in mammalian cell lines. Mutation of modified lysines in the collagenous domain prevented formation of HMW multimers, whereas a pharmacological inhibitor of prolyl- and lysyl-hydroxylases, 2,2'-dipyridyl, inhibited formation of hexamers and HMW multimers. Bacterially expressed human adiponectin displayed a complete lack of differentially modified isoforms and failed to form bona fide trimers and larger multimers. Finally, glucose-induced increases in HMW multimer production from human adipose explants correlated with changes in the two-dimensional electrophoresis profile of adiponectin isoforms. Collectively, these data suggest that adiponectin multimer composition is affected by changes in PTM in response to physiological factors.
Keyword Endocrinology & Metabolism
Core-specific Lectin
Molecular-weight Form
Brefeldin-a
Insulin Sensitivity
Metabolic Syndrome
Secretory Protein
Adipocyte
Acrp30/adiponectin
Residues
Glucose
Q-Index Code C1
Institutional Status UQ

 
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Created: Wed, 15 Aug 2007, 20:11:40 EST