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J Biol Chem. 2015 Jul 17;290(29):18111-23. doi: 10.1074/jbc.M115.663088. Epub 2015 Jun 9.

Regulation and Quality Control of Adiponectin Assembly by Endoplasmic Reticulum Chaperone ERp44.

Author information

1
From the School of Biological Science and.
2
State Key Laboratory of Pharmaceutical Biotechnology and Department of Pharmacology and Pharmacy, The University of Hong Kong, 999007 Hong Kong, China.
3
School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand, and Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand, Institute for Innovation in Biotechnology, The University of Auckland, 3A Symonds Street, Auckland 1010, New Zealand.
4
From the School of Biological Science and a.mitra@auckland.ac.nz.

Abstract

Adiponectin, a collagenous hormone secreted abundantly from adipocytes, possesses potent antidiabetic and anti-inflammatory properties. Mediated by the conserved Cys(39) located in the variable region of the N terminus, the trimeric (low molecular weight (LMW)) adiponectin subunit assembles into different higher order complexes, e.g. hexamers (middle molecular weight (MMW)) and 12-18-mers (high molecular weight (HMW)), the latter being mostly responsible for the insulin-sensitizing activity of adiponectin. The endoplasmic reticulum (ER) chaperone ERp44 retains adiponectin in the early secretory compartment and tightly controls the oxidative state of Cys(39) and the oligomerization of adiponectin. Using cellular and in vitro assays, we show that ERp44 specifically recognizes the LMW and MMW forms but not the HMW form. Our binding assays with short peptide mimetics of adiponectin suggest that ERp44 intercepts and converts the pool of fully oxidized LMW and MMW adiponectin, but not the HMW form, into reduced trimeric precursors. These ERp44-bound precursors in the cis-Golgi may be transported back to the ER and released to enhance the population of adiponectin intermediates with appropriate oxidative state for HMW assembly, thereby underpinning the process of ERp44 quality control.

KEYWORDS:

ER quality control; adiponectin; disulfide; peptide interaction; thiol

PMID:
26060250
PMCID:
PMC4505056
DOI:
10.1074/jbc.M115.663088
[Indexed for MEDLINE]
Free PMC Article

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