title: Characterisation of the adiponectin receptors: the non-conserved N-terminal region of AdipoR2 prevents its expression at the cell-surface.
abstract: Adiponectin is a beneficial adipokine with insulin-sensitizing, anti-inflammatory and anti-atherogenic effects. These effects are mediated by two poorly characterised, closely related, atypical seven-transmembrane receptors. In the current report we have used C-terminal, epitope-tagged AdipoR1 and AdipoR2 constructs to monitor cell-surface expression by indirect immunofluorescence microscopy and quantitative plate-based analysis. We demonstrate that only AdipoR1 is constitutively expressed on the cell-surface. Further investigations, involving characterisation of a number of chimeric and truncated constructs, show the non-conserved region of AdipoR2 (residues 1-81) restricts its cell-surface expression. Introduction or deletion of this region, into AdipoR1 or AdipoR2, resulted in inhibition or promotion of cell-surface expression, respectively. We also confirmed that AdipoR1 and AdipoR2 can form heterodimers when co-expressed and that co-expression leads to the cell-surface expression of AdipoR2. Collectively these studies demonstrate that the non-conserved region of AdipoR2 restricts its cell-surface expression and raise the possibility that the majority of cell-surface AdipoR2 may be present in the form of heterodimers.
authors: Mater Medical Research Institute, Brisbane, QLD, Australia.
authors: Sahar
authors: S
authors: Keshvari
authors: Felicity J
authors: FJ
authors: Rose
authors: Hayley K
authors: HK
authors: Charlton
authors: Nicole L
authors: NL
authors: Scheiber
authors: Julie
authors: J
authors: Webster
authors: Yu-Hee
authors: YH
authors: Kim
authors: Choaping
authors: C
authors: Ng
authors: Robert G
authors: RG
authors: Parton
authors: Jonathan P
authors: JP
authors: Whitehead
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism*; D006224:Cricetinae; D006801:Humans; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D054419:Receptors, Adiponectin / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: C475418:ADIPOR1 protein, human; C475420:ADIPOR2 protein, human; D054419:Receptors, Adiponectin; D011993:Recombinant Fusion Proteins