title: Role of the ubiquitin-proteasome system in the regulation of P2Y13 receptor expression: impact on hepatic HDL uptake.
abstract: The protective effect of high density lipoproteins (HDL) against atherosclerosis is mainly attributed to their capacity to transport excess cholesterol from peripheral tissues back to the liver for further elimination into the bile, a process called reverse cholesterol transport (RCT). Recently, the importance of the P2Y13 receptor (P2Y13-R) was highlighted in HDL metabolism since HDL uptake by the liver was decreased in P2Y13-R deficient mice, which translated into impaired RCT. Here, we investigated for the first time the molecular mechanisms regulating cell surface expression of P2Y13-R. When transiently expressed, P2Y13-R was mainly detected in the endoplasmic reticulum (ER) and strongly subjected to proteasome degradation while its homologous P2Y12 receptor (P2Y12-R) was efficiently targeted to the plasma membrane. We observed an inverse correlation between cell surface expression and ubiquitination level of P2Y13-R in the ER, suggesting a close link between ubiquitination of P2Y13-R and its efficient targeting to the plasma membrane. The C-terminus tail exchange between P2Y13-R and P2Y12-R strongly restored plasma membrane expression of P2Y13-R, suggesting the involvement of the intra-cytoplasmic tail of P2Y13-R in expression defect. Accordingly, proteasomal inhibition increased plasma membrane expression of functionally active P2Y13-R in hepatocytes, and consequently stimulated P2Y13-R-mediated HDL endocytosis. Importantly, proteasomal inhibition strongly potentiated HDL hepatic uptake (>200 %) in wild-type but not in P2Y13-R-deficient mice, thus reinforcing the role of P2Y13-R expression in regulating HDL metabolism. Therefore, specific inhibition of the ubiquitin-proteasome system might be a novel powerful HDL therapy to enhance P2Y13-R expression and consequently promote the overall RCT.
authors.affiliation: INSERM, UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, 31432, France, veronique.pons@inserm.fr.
authors.forename: Véronique
authors.initials: V
authors.lastname: Pons
authors.forename: Nizar
authors.initials: N
authors.lastname: Serhan
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Gayral
authors.forename: Camille
authors.initials: C
authors.lastname: Malaval
authors.forename: Michel
authors.initials: M
authors.lastname: Nauze
authors.forename: Nicole
authors.initials: N
authors.lastname: Malet
authors.forename: Muriel
authors.initials: M
authors.lastname: Laffargue
authors.forename: Céline
authors.initials: C
authors.lastname: Galés
authors.forename: Laurent O
authors.initials: LO
authors.lastname: Martinez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004705:Endocytosis; D004721:Endoplasmic Reticulum / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D058925:Receptors, Purinergic P2Y12 / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D008075:Lipoproteins, HDL; C548577:P2ry12 protein, mouse; C486689:P2ry13 protein, mouse; D018048:Receptors, Purinergic P2; D058925:Receptors, Purinergic P2Y12; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; D046988:Proteasome Endopeptidase Complex
references.citation: Biochim Biophys Acta. 2010 Dec;1801(12):1349-60
references.pmid: 20817122
references.citation: Arterioscler Thromb Vasc Biol. 2011 Sep;31(9):1980-7
references.pmid: 21817095
references.citation: Mol Cell. 2005 Sep 16;19(6):829-40
references.pmid: 16168377
references.citation: Mol Endocrinol. 2003 Apr;17(4):677-91
references.pmid: 12554793
references.citation: J Mol Histol. 2013 Aug;44(4):381-90
references.pmid: 23595775
references.citation: PLoS Biol. 2012 Jan;10(1):e1001239
references.pmid: 22253574
references.citation: J Biol Chem. 2001 Nov 2;276(44):41479-85
references.pmid: 11546776
references.citation: Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20503-8
references.pmid: 22143767
references.citation: Biochim Biophys Acta. 2006 Jul;1761(7):655-66
references.pmid: 16798073
references.citation: Cell Signal. 2009 Jan;21(1):120-7
references.pmid: 18948190
references.citation: Diabetologia. 2010 Sep;53(9):1927-34
references.pmid: 20526761
references.citation: Neuron. 2000 Jul;27(1):97-106
references.pmid: 10939334
references.citation: Hepatology. 2010 Oct;52(4):1477-83
references.pmid: 20830789
references.citation: Mol Pharmacol. 2006 Apr;69(4):1083-94
references.pmid: 16339847
references.citation: Neurosci Lett. 2012 Jun 14;518(1):5-9
references.pmid: 22521313
references.citation: Nature. 2003 Jan 2;421(6918):75-9
references.pmid: 12511957
references.citation: Cell Mol Life Sci. 2005 Nov;62(21):2508-15
references.pmid: 16231090
references.citation: J Biol Chem. 2002 Nov 22;277(47):44925-31
references.pmid: 12244098
references.citation: Pharmacol Res. 2010 Dec;62(6):500-5
references.pmid: 20813187
references.citation: PLoS One. 2012;7(3):e34192
references.pmid: 22457824
references.citation: Trends Pharmacol Sci. 2008 Oct;29(10):528-35
references.pmid: 18760490
references.citation: Circ Res. 2005 Feb 4;96(2):189-96
references.pmid: 15604418
references.citation: Biochim Biophys Acta. 2013 Apr;1831(4):719-25
references.pmid: 23266391
references.citation: Nat Rev Mol Cell Biol. 2008 Dec;9(12):944-57
references.pmid: 19002207
references.citation: Science. 1996 Jan 26;271(5248):518-20
references.pmid: 8560269
references.citation: Clin Cancer Res. 2007 Jan 1;13(1):27-37
references.pmid: 17200335
references.citation: Arterioscler Thromb Vasc Biol. 2007 May;27(5):1132-8
references.pmid: 17322101
references.citation: Nat Methods. 2004 Dec;1(3):203-8
references.pmid: 15782195
references.citation: Mol Pharmacol. 2012 Oct;82(4):563-70
references.pmid: 22700696
references.citation: PLoS Biol. 2012 Jan;10(1):e1001238
references.pmid: 22253573
references.citation: Mol Endocrinol. 2012 Jan;26(1):142-52
references.pmid: 22108801
references.citation: Science. 2009 Jul 3;325(5936):100-4
references.pmid: 19520913
references.citation: Biochem J. 1999 Apr 15;339 ( Pt 2):397-405
references.pmid: 10191272
references.citation: Proc Natl Acad Sci U S A. 2004 Sep 14;101(37):13672-6
references.pmid: 15347813