title: Par-3 modulates intestinal epithelial barrier function through regulating intracellular trafficking of occludin and myosin light chain phosphorylation.
abstract: BACKGROUND
  Tight junctions play a critical role in the maintenance of intestinal barrier function. Partitioning-defective protein 3 (Par-3) can regulate intestinal barrier function through the modulation of tight junction assembly and cell polarity. However, the mechanisms are still not fully understood.
  
  
  METHODS
  Adult C57BL/6 mice were treated with dextran sulfate sodium for 7 days, and segments of colon were harvested for immunofluorescent staining of Par-3. Caco-2 intestinal epithelial cells were treated with tumor necrosis factor α (TNF-α) for 24 h, and Par-3 expression was detected by Western blot analysis and immunofluorescence. Additionally, Caco-2 cells were treated with Par-3 small interfering RNA, and altered expression and subcellular localization of tight junction proteins were studied by Western blot analysis and immunofluorescence. Furthermore, the interaction between Par-3 and myosin light chain (MLC) was detected by immunoprecipitation.
  
  
  RESULTS
  Par-3 was downregulated in murine dextran sulfate sodium induced acute inflammation and TNF-α-treated Caco-2 cells. Depletion of Par-3 expression by small interfering RNA delayed intestinal epithelial barrier development in Caco-2 cells. This regulation was due to the redistribution of the tight junction protein occludin rather than the altered total levels of tight junction proteins. Par-3 silencing blocked the trafficking of occludin from or through the Golgi complex to the cell surface, and dramatically induced occludin accumulated at the Golgi complex. Importantly, Par-3 can interact with MLC, and loss of Par-3 upregulated MLC kinase expression and MLC phosphorylation, which contributed to intestinal epithelial barrier dysfunction.
  
  
  CONCLUSIONS
  These results indicate that Par-3 plays an important role in the modulation of intestinal barrier function by regulating delivery of occludin as well as suppression of MLC phosphorylation.
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yu
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Songwei
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Xu
authors.affiliation: Center of Medical Experiment and Technology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Wenqiang
authors.initials: W
authors.lastname: Cai
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China. huayang@tmmu.edu.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D018938:Caco-2 Cells; D015815:Cell Adhesion Molecules / Q000172:deficiency / Q000502:physiology; D018797:Cell Cycle Proteins / Q000172:deficiency / Q000502:physiology*; D003106:Colon / Q000378:metabolism; D016264:Dextran Sulfate; D015536:Down-Regulation / Q000502:physiology; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000378:metabolism* / Q000503:physiopathology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency / Q000502:physiology*; D008810:Mice, Inbred C57BL; D018994:Myosin Light Chains / Q000378:metabolism*; D062793:Occludin / Q000378:metabolism*; D010766:Phosphorylation
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; D008565:Membrane Proteins; D018994:Myosin Light Chains; C568985:OCLN protein, human; D062793:Occludin; C568986:Ocln protein, mouse; C509689:PARD3 protein, human; C115084:Pard3 protein, mouse; D016264:Dextran Sulfate
keywords: Golgi; Intestinal barrier function; Myosin light chain; Partitioning-defective protein 3; Tight junction
references.citation: Am J Physiol Cell Physiol. 2012 Jan 1;302(1):C178-87
references.pmid: 21956164
references.citation: Am J Gastroenterol. 2002 Aug;97(8):2000-4
references.pmid: 12190167
references.citation: Am J Physiol Cell Physiol. 2007 Mar;292(3):C1094-102
references.pmid: 16928777
references.citation: J Membr Biol. 1998 Feb 1;161(3):263-74
references.pmid: 9493132
references.citation: Prog Biophys Mol Biol. 2003 Jan;81(1):1-44
references.pmid: 12475568
references.citation: Ann N Y Acad Sci. 2009 May;1165:220-7
references.pmid: 19538310
references.citation: Gut. 2008 Apr;57(4):463-7
references.pmid: 17989107
references.citation: Exp Cell Res. 2013 Jun 10;319(10):1357-64
references.pmid: 23535009
references.citation: J Cell Biol. 1997 Jan 27;136(2):399-409
references.pmid: 9015310
references.citation: J Cell Sci. 1996 Sep;109 ( Pt 9):2287-98
references.pmid: 8886979
references.citation: Biochim Biophys Acta. 2008 Mar;1778(3):646-59
references.pmid: 17945185
references.citation: Nat Cell Biol. 2005 Mar;7(3):262-9
references.pmid: 15723052
references.citation: J Interferon Cytokine Res. 2014 Mar;34(3):195-203
references.pmid: 24237301
references.citation: FASEB J. 2005 Jun;19(8):923-33
references.pmid: 15923402
references.citation: Front Biosci (Landmark Ed). 2009 Jan 01;14:2765-78
references.pmid: 19273235
references.citation: J Cell Sci. 2006 May 15;119(Pt 10):2095-106
references.pmid: 16638813
references.citation: Mol Biol Cell. 2015 Feb 15;26(4):751-61
references.pmid: 25518939
references.citation: World J Gastroenterol. 2008 Sep 7;14(33):5154-61
references.pmid: 18777592
references.citation: Ann N Y Acad Sci. 2009 May;1165:195-205
references.pmid: 19538307
references.citation: Mol Biol Cell. 2000 Dec;11(12):4131-42
references.pmid: 11102513
references.citation: Mol Biol Cell. 2010 Apr 1;21(7):1200-13
references.pmid: 20164257
references.citation: Int J Colorectal Dis. 2004 Jul;19(4):308-15
references.pmid: 14605835
references.citation: Gut. 2012 Feb;61(2):220-8
references.pmid: 21865402
references.citation: Curr Opin Gastroenterol. 2007 Jul;23(4):379-83
references.pmid: 17545772
references.citation: Int Immunopharmacol. 2008 Jun;8(6):836-44
references.pmid: 18442787
references.citation: Mol Biol Cell. 2012 May;23(9):1783-96
references.pmid: 22398721
references.citation: J Biol Chem. 2001 Aug 10;276(32):30342-9
references.pmid: 11384975
references.citation: EMBO J. 2012 Oct 17;31(20):3976-90
references.pmid: 22909819
references.citation: Am J Physiol Cell Physiol. 2005 Jun;288(6):C1231-41
references.pmid: 15689410
references.citation: J Cell Biol. 1996 Aug;134(4):1031-49
references.pmid: 8769425
references.citation: Am J Pathol. 2006 Dec;169(6):1901-9
references.pmid: 17148655
references.citation: Am J Physiol. 1999 May;276(5 Pt 1):G1279-88
references.pmid: 10330020
references.citation: Trends Cell Biol. 2014 Oct;24(10):584-93
references.pmid: 24841758
references.citation: Annu Rev Cell Dev Biol. 2006;22:207-35
references.pmid: 16771626
references.citation: Mol Biol Cell. 2004 Jan;15(1):176-88
references.pmid: 14528017
references.citation: Cancer Cell. 2012 Nov 13;22(5):601-14
references.pmid: 23153534
references.citation: Nat Cell Biol. 2000 Aug;2(8):531-9
references.pmid: 10934474
references.citation: J Cell Biol. 2010 Apr 5;189(1):111-26
references.pmid: 20351069
references.citation: Infect Immun. 1998 Jun;66(6):2410-9
references.pmid: 9596696
references.citation: Am J Physiol Gastrointest Liver Physiol. 2008 Apr;294(4):G938-47
references.pmid: 18258792
references.citation: Mol Biol Cell. 2005 Sep;16(9):3919-36
references.pmid: 15958494
references.citation: Am J Physiol Gastrointest Liver Physiol. 2000 Nov;279(5):G851-7
references.pmid: 11052980
references.citation: J Immunol. 2003 Dec 1;171(11):6164-72
references.pmid: 14634132
references.citation: Ann N Y Acad Sci. 2012 Jul;1258:34-42
references.pmid: 22731713