title: Expression and lysosomal targeting of CLN7, a major facilitator superfamily transporter associated with variant late-infantile neuronal ceroid lipofuscinosis.
abstract: Neuronal ceroid lipofuscinoses (NCLs) constitute a group of progressive neurodegenerative disorders resulting from mutations in at least eight different genes. Mutations in the most recently identified NCL gene, MFSD8/CLN7, underlie a variant of late-infantile NCL (vLINCL). The MFSD8/CLN7 gene encodes a polytopic protein with unknown function, which shares homology with ion-coupled membrane transporters. In this study, we confirmed the lysosomal localization of the native CLN7 protein. This localization of CLN7 is not impaired by the presence of pathogenic missense mutations or after genetic ablation of the N-glycans. Expression of chimeric and full-length constructs showed that lysosomal targeting of CLN7 is mainly determined by an N-terminal dileucine motif, which specifically binds to the heterotetrameric adaptor AP-1 in vitro. We also show that CLN7 mRNA is more abundant in neurons than astrocytes and microglia, and that it is expressed throughout rat brain, with increased levels in the granular layer of cerebellum and hippocampal pyramidal cells. Interestingly, this cellular and regional distribution is in good agreement with the autofluorescent lysosomal storage and cell loss patterns found in brains from CLN7-defective patients. Overall, these data highlight lysosomes as the primary site of action for CLN7, and suggest that the pathophysiology underpinning CLN7-associated vLINCL is a cell-autonomous process.
authors.affiliation: Institut de Biologie Physico-Chimique, Université Paris Descartes, Centre National de la Recherche Scientifique, UMR 8192, Institut de Biologie Physico-Chimique, 13 Rue P. et M. Curie, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Sharifi
authors.forename: M
authors.initials: M
authors.lastname: Kousi
authors.forename: C
authors.initials: C
authors.lastname: Sagné
authors.forename: G C
authors.initials: GC
authors.lastname: Bellenchi
authors.forename: L
authors.initials: L
authors.lastname: Morel
authors.forename: M
authors.initials: M
authors.lastname: Darmon
authors.forename: H
authors.initials: H
authors.lastname: Hulková
authors.forename: R
authors.initials: R
authors.lastname: Ruivo
authors.forename: C
authors.initials: C
authors.lastname: Debacker
authors.forename: S
authors.initials: S
authors.lastname: El Mestikawy
authors.forename: M
authors.initials: M
authors.lastname: Elleder
authors.forename: A-E
authors.initials: AE
authors.lastname: Lehesjoki
authors.forename: A
authors.initials: A
authors.lastname: Jalanko
authors.forename: B
authors.initials: B
authors.lastname: Gasnier
authors.forename: A
authors.initials: A
authors.lastname: Kyttälä
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D057809:HEK293 Cells; D006367:HeLa Cells; D006720:Homozygote; D006801:Humans; D008247:Lysosomes / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D009472:Neuronal Ceroid-Lipofuscinoses / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: C522398:MFSD8 protein, human; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D018808:Transcription Factor AP-1
references.citation: Hum Mutat. 2009 Mar;30(3):E530-40
references.pmid: 19177532
references.citation: Biochim Biophys Acta. 2009 Apr;1793(4):636-49
references.pmid: 19146888
references.citation: Microbiol Mol Biol Rev. 1998 Mar;62(1):1-34
references.pmid: 9529885
references.citation: Cell. 2008 Nov 28;135(5):838-51
references.pmid: 19041749
references.citation: Brain. 2009 Mar;132(Pt 3):810-9
references.pmid: 19201763
references.citation: Nature. 1995 Aug 17;376(6541):584-7
references.pmid: 7637805
references.citation: Hum Mutat. 2010 Mar;31(3):356-65
references.pmid: 20052765
references.citation: Hum Mol Genet. 2001 Sep 15;10(19):2123-31
references.pmid: 11590129
references.citation: Biochim Biophys Acta. 2009 Apr;1793(4):605-14
references.pmid: 19046998
references.citation: Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1541-5
references.pmid: 8381971
references.citation: Am J Hum Genet. 2002 Feb;70(2):537-42
references.pmid: 11727201
references.citation: Curr Biol. 2006 Feb 21;16(4):408-14
references.pmid: 16488876
references.citation: Mol Cell Proteomics. 2005 Feb;4(2):133-43
references.pmid: 15579476
references.citation: Neurogenetics. 2009 Feb;10(1):73-7
references.pmid: 18850119
references.citation: Hum Mol Genet. 2010 Mar 1;19(5):837-47
references.pmid: 20007718
references.citation: Science. 2004 Oct 1;306(5693):120-4
references.pmid: 15459394
references.citation: Traffic. 2010 Jul 1;11(7):987-1000
references.pmid: 20406422
references.citation: J Neurosci. 2010 Feb 10;30(6):2198-210
references.pmid: 20147547
references.citation: J Inherit Metab Dis. 2008 Apr;31(2):258-66
references.pmid: 18425435
references.citation: Traffic. 2007 Dec;8(12):1676-1686
references.pmid: 17897319
references.citation: Hum Mol Genet. 1999 Jun;8(6):1091-8
references.pmid: 10332042
references.citation: Hum Mol Genet. 2000 Jul 1;9(11):1691-7
references.pmid: 10861296
references.citation: Biochem J. 1991 May 15;276 ( Pt 1):251-6
references.pmid: 2039475
references.citation: BMC Cell Biol. 2009 Nov 26;10:83
references.pmid: 19941651
references.citation: Traffic. 2005 Dec;6(12):1196-212
references.pmid: 16262729
references.citation: Mol Biol Cell. 2004 Mar;15(3):1313-23
references.pmid: 14699076
references.citation: Nat Genet. 1998 Jul;19(3):286-8
references.pmid: 9662406
references.citation: J Biol Chem. 2001 Dec 28;276(52):49183-7
references.pmid: 11598115
references.citation: Am J Hum Genet. 2002 Feb;70(2):324-35
references.pmid: 11791207
references.citation: Am J Hum Genet. 2007 Jul;81(1):136-46
references.pmid: 17564970
references.citation: J Biol Chem. 2004 May 21;279(21):22347-52
references.pmid: 15010453
references.citation: J Biol Chem. 2005 Jan 14;280(2):1408-16
references.pmid: 15516337
references.citation: PLoS Genet. 2005 Jul;1(1):81-95
references.pmid: 16103921
references.citation: Nat Protoc. 2008;3(6):1101-8
references.pmid: 18546601
references.citation: J Neurosci. 1986 Oct;6(10):3044-60
references.pmid: 3760948
references.citation: J Biol Chem. 2005 Mar 18;280(11):10277-83
references.pmid: 15598649
references.citation: Proc Natl Acad Sci U S A. 2008 Jul 15;105(28):9805-10
references.pmid: 18606998
references.citation: Dev Biol. 1991 Mar;144(1):16-29
references.pmid: 1995394
references.citation: Cell. 1995 Sep 22;82(6):949-57
references.pmid: 7553855
references.citation: Biochim Biophys Acta. 2009 Apr;1793(4):697-709
references.pmid: 19084560
references.citation: Neurogenetics. 2009 Oct;10(4):307-11
references.pmid: 19277732
references.citation: Annu Rev Biochem. 2003;72:395-447
references.pmid: 12651740
references.citation: Turk J Pediatr. 2004 Jan-Mar;46(1):1-10
references.pmid: 15074367
references.citation: Exp Cell Res. 2004 Aug 15;298(2):399-406
references.pmid: 15265688
references.citation: J Biol Chem. 1998 Jan 30;273(5):2729-37
references.pmid: 9446579
references.citation: Brain. 2006 Jun;129(Pt 6):1438-45
references.pmid: 16670177
references.citation: Biochim Biophys Acta. 2006 Oct;1762(10):920-33
references.pmid: 16839750
references.citation: J Neurosci. 2008 Aug 6;28(32):8063-73
references.pmid: 18685031
references.citation: J Biol Chem. 2001 Apr 20;276(16):13314-21
references.pmid: 11150305
references.citation: Science. 2001 Feb 9;291(5506):1051-5
references.pmid: 11161218
references.citation: Am J Hum Genet. 2006 Jun;78(6):988-98
references.pmid: 16685649
references.citation: EMBO J. 2001 Nov 1;20(21):5940-9
references.pmid: 11689434
references.citation: Mol Biol Cell. 2009 Mar;20(5):1464-77
references.pmid: 19116314
references.citation: Nat Neurosci. 2008 Mar;11(3):292-300
references.pmid: 18278042
references.citation: EMBO J. 2004 Nov 24;23(23):4560-70
references.pmid: 15510212
references.citation: Science. 1997 Sep 19;277(5333):1802-5
references.pmid: 9295267
references.citation: FASEB J. 2009 Dec;23(12):4056-68
references.pmid: 19661288
references.citation: Nat Genet. 1999 Oct;23(2):233-6
references.pmid: 10508524
references.citation: Traffic. 2008 Nov;9(11):1905-14
references.pmid: 18817525
references.citation: Biochem J. 2000 Jan 15;345 Pt 2:287-96
references.pmid: 10620506