title: Shank2 redistributes with NaPilla during regulated endocytosis.
abstract: Serum phosphate levels are acutely impacted by the abundance of sodium-phosphate cotransporter IIa (NaPiIIa) in the apical membrane of renal proximal tubule cells. PSD-95/Disks Large/Zonula Occludens (PDZ) domain-containing proteins bind NaPiIIa and likely contribute to the delivery, retention, recovery, and trafficking of NaPiIIa. Shank2 is a distinctive PDZ domain protein that binds NaPiIIa. Its role in regulating NaPiIIa activity, distribution, and abundance is unknown. In the present in vivo study, rats were maintained on a low-phosphate diet, and then plasma phosphate levels were acutely elevated by high-phosphate feeding to induce the recovery, endocytosis, and degradation of NaPiIIa. Western blot analysis of renal cortical tissue from rats given high-phosphate feed showed NaPiIIa and Shank2 underwent degradation. Quantitative immunofluorescence analyses, including microvillar versus intracellular intensity ratios and intensity correlation quotients, showed that Shank2 redistributed with NaPiIIa during the time course of NaPiIIa endocytosis. Furthermore, NaPiIIa and Shank2 trafficked through distinct endosomal compartments (clathrin, early endosomes, lysosomes) with the same temporal pattern. These in vivo findings indicate that Shank2 is positioned to coordinate the regulated endocytic retrieval and downregulation of NaPiIIa in rat renal proximal tubule cells.
authors.affiliation: Department of Medicine, Anschutz Medical Center, University of Colorado, Denver, Colorado, USA.
authors.forename: Evgenia
authors.initials: E
authors.lastname: Dobrinskikh
authors.forename: Hector
authors.initials: H
authors.lastname: Giral
authors.forename: Yupanqui A
authors.initials: YA
authors.lastname: Caldas
authors.forename: Moshe
authors.initials: M
authors.lastname: Levi
authors.forename: R Brian
authors.initials: RB
authors.lastname: Doctor
mesh_terms: D000818:Animals; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D007672:Kidney Cortex / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism; D008297:Male; D008871:Microvilli / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000378:metabolism*; D010710:Phosphates / Q000097:blood; D016226:Phosphorus, Dietary / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D050613:Sodium-Phosphate Cotransporter Proteins, Type IIa / Q000032:analysis / Q000378:metabolism*
chemical_list: D002966:Clathrin; D009419:Nerve Tissue Proteins; D010710:Phosphates; D016226:Phosphorus, Dietary; C485686:Shank2 protein, rat; D050613:Sodium-Phosphate Cotransporter Proteins, Type IIa
references.citation: Am J Physiol. 1995 Apr;268(4 Pt 2):F784-91
references.pmid: 7733336
references.citation: Nat Cell Biol. 2006 Sep;8(9):945-56
references.pmid: 16892055
references.citation: J Biol Chem. 2004 Mar 12;279(11):10389-96
references.pmid: 14679199
references.citation: J Clin Endocrinol Metab. 2006 Oct;91(10):4022-7
references.pmid: 16849419
references.citation: N Engl J Med. 2010 Mar 25;362(12):1102-9
references.pmid: 20335586
references.citation: Am J Hum Genet. 2006 Feb;78(2):179-92
references.pmid: 16358214
references.citation: Annu Rev Neurosci. 2001;24:1-29
references.pmid: 11283303
references.citation: Am J Physiol. 1994 Nov;267(5 Pt 2):F900-8
references.pmid: 7977794
references.citation: Mol Cell Biol. 2003 Feb;23(4):1175-80
references.pmid: 12556478
references.citation: Physiology (Bethesda). 2006 Oct;21:352-61
references.pmid: 16990456
references.citation: Mol Cell Biol. 1998 Oct;18(10):5838-51
references.pmid: 9742101
references.citation: Trends Biochem Sci. 1995 Sep;20(9):350
references.pmid: 7482701
references.citation: J Biol Chem. 2003 May 23;278(21):19220-9
references.pmid: 12626503
references.citation: Am J Physiol. 1993 Apr;264(4 Pt 1):C1003-13
references.pmid: 8386446
references.citation: Oncogene. 2006 May 18;25(21):3071-8
references.pmid: 16407834
references.citation: Am J Physiol Cell Physiol. 2005 Jul;289(1):C159-67
references.pmid: 15788483
references.citation: Proc Natl Acad Sci U S A. 2002 Aug 20;99(17):11470-5
references.pmid: 12169661
references.citation: J Biol Chem. 2001 Dec 21;276(51):48458-65
references.pmid: 11583995
references.citation: Nat Rev Neurosci. 2004 Oct;5(10):771-81
references.pmid: 15378037
references.citation: Pflugers Arch. 2005 Jan;449(4):392-402
references.pmid: 15517343
references.citation: Biochem J. 1998 Jul 1;333 ( Pt 1):175-81
references.pmid: 9639577
references.citation: Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1909-14
references.pmid: 9465116
references.citation: Biochem J. 2004 May 15;380(Pt 1):181-91
references.pmid: 14977424
references.citation: J Biol Chem. 2006 Jan 20;281(3):1461-9
references.pmid: 16293618
references.citation: J Biol Chem. 2001 Mar 23;276(12):9206-13
references.pmid: 11099500
references.citation: J Neurosci. 2004 Apr 21;24(16):4070-81
references.pmid: 15102922
references.citation: J Biol Chem. 2002 Feb 15;277(7):5644-50
references.pmid: 11741931
references.citation: Nat Rev Neurosci. 2009 Feb;10(2):87-99
references.pmid: 19153575
references.citation: J Histochem Cytochem. 2001 May;49(5):639-48
references.pmid: 11304802
references.citation: Am J Physiol Cell Physiol. 2005 Oct;289(4):C1042-51
references.pmid: 15917299
references.citation: Am J Hum Genet. 2006 Feb;78(2):193-201
references.pmid: 16358215
references.citation: Nat Rev Mol Cell Biol. 2004 Feb;5(2):133-47
references.pmid: 15040446
references.citation: Kidney Int. 1998 Oct;54(4):1224-32
references.pmid: 9767538
references.citation: Kidney Int. 2006 Nov;70(9):1548-59
references.pmid: 16955105
references.citation: Proc Natl Acad Sci U S A. 2002 Sep 3;99(18):11957-62
references.pmid: 12192091