Expression and lysosomal targeting of CLN7, a major facilitator superfamily transporter associated with variant late-infantile neuronal ceroid lipofuscinosis.
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.
Sharifi
A
A
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.
Kousi
M
M
Sagné
C
C
Bellenchi
G C
GC
Morel
L
L
Darmon
M
M
Hulková
H
H
Ruivo
R
R
Debacker
C
C
El Mestikawy
S
S
Elleder
M
M
Lehesjoki
A-E
AE
Jalanko
A
A
Gasnier
B
B
Kyttälä
A
A
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
C522398:MFSD8 protein, human; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D018808:Transcription Factor AP-1
Hum Mutat. 2009 Mar;30(3):E530-40
19177532
Biochim Biophys Acta. 2009 Apr;1793(4):636-49
19146888
Microbiol Mol Biol Rev. 1998 Mar;62(1):1-34
9529885
Cell. 2008 Nov 28;135(5):838-51
19041749
Brain. 2009 Mar;132(Pt 3):810-9
19201763
Nature. 1995 Aug 17;376(6541):584-7
7637805
Hum Mutat. 2010 Mar;31(3):356-65
20052765
Hum Mol Genet. 2001 Sep 15;10(19):2123-31
11590129
Biochim Biophys Acta. 2009 Apr;1793(4):605-14
19046998
Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1541-5
8381971
Am J Hum Genet. 2002 Feb;70(2):537-42
11727201
Curr Biol. 2006 Feb 21;16(4):408-14
16488876
Mol Cell Proteomics. 2005 Feb;4(2):133-43
15579476
Neurogenetics. 2009 Feb;10(1):73-7
18850119
Hum Mol Genet. 2010 Mar 1;19(5):837-47
20007718
Science. 2004 Oct 1;306(5693):120-4
15459394
Traffic. 2010 Jul 1;11(7):987-1000
20406422
J Neurosci. 2010 Feb 10;30(6):2198-210
20147547
J Inherit Metab Dis. 2008 Apr;31(2):258-66
18425435
Traffic. 2007 Dec;8(12):1676-1686
17897319
Hum Mol Genet. 1999 Jun;8(6):1091-8
10332042
Hum Mol Genet. 2000 Jul 1;9(11):1691-7
10861296
Biochem J. 1991 May 15;276 ( Pt 1):251-6
2039475
BMC Cell Biol. 2009 Nov 26;10:83
19941651
Traffic. 2005 Dec;6(12):1196-212
16262729
Mol Biol Cell. 2004 Mar;15(3):1313-23
14699076
Nat Genet. 1998 Jul;19(3):286-8
9662406
J Biol Chem. 2001 Dec 28;276(52):49183-7
11598115
Am J Hum Genet. 2002 Feb;70(2):324-35
11791207
Am J Hum Genet. 2007 Jul;81(1):136-46
17564970
J Biol Chem. 2004 May 21;279(21):22347-52
15010453
J Biol Chem. 2005 Jan 14;280(2):1408-16
15516337
PLoS Genet. 2005 Jul;1(1):81-95
16103921
Nat Protoc. 2008;3(6):1101-8
18546601
J Neurosci. 1986 Oct;6(10):3044-60
3760948
J Biol Chem. 2005 Mar 18;280(11):10277-83
15598649
Proc Natl Acad Sci U S A. 2008 Jul 15;105(28):9805-10
18606998
Dev Biol. 1991 Mar;144(1):16-29
1995394
Cell. 1995 Sep 22;82(6):949-57
7553855
Biochim Biophys Acta. 2009 Apr;1793(4):697-709
19084560
Neurogenetics. 2009 Oct;10(4):307-11
19277732
Annu Rev Biochem. 2003;72:395-447
12651740
Turk J Pediatr. 2004 Jan-Mar;46(1):1-10
15074367
Exp Cell Res. 2004 Aug 15;298(2):399-406
15265688
J Biol Chem. 1998 Jan 30;273(5):2729-37
9446579
Brain. 2006 Jun;129(Pt 6):1438-45
16670177
Biochim Biophys Acta. 2006 Oct;1762(10):920-33
16839750
J Neurosci. 2008 Aug 6;28(32):8063-73
18685031
J Biol Chem. 2001 Apr 20;276(16):13314-21
11150305
Science. 2001 Feb 9;291(5506):1051-5
11161218
Am J Hum Genet. 2006 Jun;78(6):988-98
16685649
EMBO J. 2001 Nov 1;20(21):5940-9
11689434
Mol Biol Cell. 2009 Mar;20(5):1464-77
19116314
Nat Neurosci. 2008 Mar;11(3):292-300
18278042
EMBO J. 2004 Nov 24;23(23):4560-70
15510212
Science. 1997 Sep 19;277(5333):1802-5
9295267
FASEB J. 2009 Dec;23(12):4056-68
19661288
Nat Genet. 1999 Oct;23(2):233-6
10508524
Traffic. 2008 Nov;9(11):1905-14
18817525
Biochem J. 2000 Jan 15;345 Pt 2:287-96
10620506