| 2001 |
CLN6 encodes a novel ~36 kDa transmembrane protein with predicted membrane-spanning domains; mutations in human patients (stop codon, codon deletion) and a frameshift in the nclf mouse cause neuronal ceroid lipofuscinosis, establishing CLN6 as the causative gene for vLINCL. |
Positional cloning, haplotype analysis, DNA sequencing of patients and nclf mouse |
American journal of human genetics |
High |
11727201 11791207
|
| 2001 |
CLN6 encodes a 311-amino acid protein with seven predicted transmembrane domains, conserved across vertebrates, with no homology to proteins of known function; a disease mutation affecting a conserved residue in the predicted third hydrophilic loop suggests functional importance of that domain. |
Sequence analysis, transmembrane topology prediction, mutation mapping |
American journal of human genetics |
Medium |
11727201 11791207
|
| 2004 |
CLN6 protein resides in the endoplasmic reticulum (ER); CLN6-GFP fusion expressed in HEK293 cells co-localizes with ER markers, and five disease-causing CLN6 missense mutations are retained in the ER without trafficking to Golgi or lysosomes. |
Immunofluorescence microscopy, GFP-tagged CLN6 expression, Western blotting with CLN6-specific antisera |
Experimental cell research |
High |
15010453 15265688
|
| 2004 |
CLN6 does not undergo proteolytic processing and forms homodimers (detected by cross-linking); it is retained in the ER with no co-localization with cis-Golgi or lysosomal markers. The ER translocation and proper folding of a mutant CLN6 polypeptide was confirmed by N-linked glycosylation of an engineered mutant. |
Transient transfection, immunoblot, cross-linking experiments, double immunofluorescence microscopy, N-linked glycosylation assay |
The Journal of biological chemistry |
High |
15010453
|
| 2004 |
CLN6 deficiency (in patient fibroblasts and sheep/mouse models) does not affect synthesis, sorting, or proteolytic processing of cathepsin D, but strongly reduces lysosomal degradation of endocytosed arylsulfatase A, linking the ER-resident CLN6 protein to downstream lysosomal function. |
Pulse-chase labeling, immunoprecipitation of cathepsin D, degradation assay of endocytosed arylsulfatase A in patient and animal-model cell lines |
The Journal of biological chemistry |
High |
15010453
|
| 2007 |
CLN6 topology was established experimentally: N-terminal cytoplasmic domain, seven transmembrane domains, and a luminal C-terminus. ER retention depends on both the N-terminal cytosolic domain and transmembrane domains 6 and 7; deletion of a dilysine motif partially impairs ER localization; CLN6 homodimerization may also contribute to ER retention. |
Differential membrane permeabilization with specific detergents and antibodies, mutational analysis, confocal immunofluorescence microscopy of fusion/deletion constructs in BHK and neuronal cells |
Molecular membrane biology |
High |
17453415
|
| 2009 |
CLN6 physically interacts with CRMP-2 (collapsin response mediator protein-2); in nclf mice lacking functional CLN6, CRMP-2 protein levels are reduced in the brain (particularly thalamus), and hippocampal neurons from nclf mice show impaired maturation and increased cell death in culture. |
Co-immunoprecipitation (pulldown), Western blotting, hippocampal neuron culture, dorsal root ganglion repulsion assay |
Journal of neuroscience research |
Medium |
19235893
|
| 2009 |
CLN6 disease-associated mutants (G123D and M241T) undergo rapid proteasome-mediated degradation and associate with ER extraction machinery components Derlin-1 and p97; knockdown of SEL1L (an E3 ubiquitin ligase complex member) rescues significant amounts of mutant Cln6 polypeptides, implicating ER quality control/ERAD in CLN6 mutant turnover. |
Co-immunoprecipitation, siRNA knockdown of SEL1L, proteasome inhibitor experiments in neuronal-derived human cells |
Bioscience reports |
Medium |
18811591
|
| 2010 |
Three CLN6 patient mutations (p.Gly123Asp, p.Ile154del, p.Arg106ProfsX26) reduce the rate of synthesis and stability of CLN6 protein in a mutation-dependent manner; the truncated p.Arg106ProfsX26 mutant (equivalent to nclf mouse mutation) is rapidly degraded primarily by the proteasome and partially by lysosomal proteases; none of the mutations prevented CLN6 dimerization. |
Pulse-chase labeling, proteasomal and lysosomal inhibitor treatment, expression studies in patient and transfected cells |
Human mutation |
Medium |
20020536
|
| 2012 |
In nclf mouse brains, CLN6 deficiency leads to age-dependent increases in LC3-II, ubiquitinated proteins, and neuronal p62-positive aggregates, indicating disruption of the autophagy-lysosome pathway; this is most likely due to defective autophagosome-lysosome fusion rather than ER stress or unfolded protein response activation. The mutant Cln6 protein with reduced half-life is degraded by the proteasome. |
Western blotting for LC3-II, ubiquitin, p62; immunofluorescence; proteasomal inhibitor assays; analysis of ER stress markers across brain regions and developmental time points in nclf mice |
PloS one |
Medium |
22536393
|
| 2017 |
CLN6, an ER transmembrane protein, physically interacts with ER-anchored αB-crystallin (TMαBC) and operates as a downstream effector of TMαBC's anti-aggregate activity; CLN6 knockdown attenuates TMαBC's ability to prevent R120G αBC aggregation, while CLN6 overexpression enhances it; CLN6 directly interacts with the aggregation-prone R120G αBC mutant and suppresses its aggregation, dependent on an intact autophagy-lysosome system. |
Co-immunoprecipitation/pulldown (isolation of TMαBC-binding proteins), siRNA knockdown, overexpression in HeLa cells, aggregate formation assay, lysosomal inhibitor treatment |
Biochemical and biophysical research communications |
Medium |
28476624
|
| 2020 |
CLN6 forms an obligate complex with CLN8 at the ER (termed EGRESS: ER-to-Golgi relaying of enzymes of the lysosomal system) that recruits lysosomal enzymes at the ER to promote their Golgi transfer; the second luminal loop of CLN6 is required for interaction with lysosomal enzymes but not for interaction with CLN8; CLN6 deficiency results in inefficient ER export of lysosomal enzymes and reduced lysosomal enzyme levels; mice lacking both CLN6 and CLN8 show no aggravated pathology compared to single knockouts, indicating EGRESS functions as a single unit. |
Co-immunoprecipitation, protein interaction assays, CLN6 mutagenesis (luminal loop deletions), trafficking assays in vitro and in vivo, double-knockout mouse analysis |
The Journal of clinical investigation |
High |
32597833
|
| 2020 |
CLN6 disease-causing mutations reduce CLN6's anti-aggregate activity in a graded, mutation-dependent manner; the truncating Arg106ProfsX mutant (late infantile onset) abolishes anti-aggregate activity against all αBC mutants tested, while Arg149Cys and Arg149His adult-onset mutants retain partial activity; this graded reduction is proposed to govern disease severity. |
Overexpression of CLN6 mutants in cell-based aggregation assay using αB-crystallin mutants as substrates |
Biochemical and biophysical research communications |
Medium |
32171521
|
| 2021 |
CLN6's luminal tail (C-terminal region) participates in a conformational mechanism: the S132CfsX18 truncated mutant nullifies the anti-aggregate activity of the P299L missense CLN6 mutant (but not wild-type CLN6); resistance of wild-type CLN6 to the truncated mutant is lost when amino acids 297-301 (including Pro297/299) are mutated to alanine, suggesting Pro297/299 maintain a conformational constraint on the luminal tail needed for anti-aggregate activity. |
Cell-based aggregation assay, alanine substitution mutagenesis, deletion constructs expressed in HeLa cells |
Biomedical research (Tokyo, Japan) |
Medium |
34380921
|
| 2021 |
CLN6 deficiency causes selective reduction in specific lysosomal protein amounts, particularly N-glycosylated soluble hydrolases including several other NCL family proteins, as shown by comparative proteomics of isolated lysosomal fractions from nclf mouse liver, verified by Western blotting and enzymatic assays. |
Lysosomal fraction isolation, comparative proteomics (mass spectrometry), Western blotting, enzymatic activity assays in nclf mouse liver |
Proteomics |
Medium |
34432360
|
| 2024 |
Pro-cathepsin D (proCTSD) prevents protein aggregation through functional association with CLN6 in the ER microenvironment: proCTSD was identified as a binding partner of ER-anchored αBC; CLN6 depletion abolishes proCTSD's anti-aggregate activity; the pro-peptide integrity of CTSD is required for this activity, and the activity occurs before lysosomal processing of CTSD. |
Co-immunoprecipitation (isolation of ER-anchored αBC binding proteins), overexpression of CTSD variants including an ER-retained mutant, CLN6 knockdown, aggregate formation assay in HeLa cells |
Molecular genetics and metabolism |
Medium |
39032464
|
| 2003 |
Enhanced expression and activity of manganese-dependent superoxide dismutase (MnSOD) was found in fibroblasts and brain of human CLN6 patients and sheep OCL6 model by 2D electrophoresis, MS, immunoblotting, and enzyme activity assays, suggesting oxidative stress as a feature of CLN6 disease pathogenesis. |
2D electrophoresis, mass spectrometry, immunoblotting, MnSOD enzyme activity assay, confocal fluorescence microscopy, immunohistochemistry |
The Biochemical journal |
Medium |
12946273
|
| 2024 |
CLN6-IPSC-derived neurons show decreased tripeptidyl peptidase-1 (TPP1) activity and increased LAMP1+ signal in cell bodies and neurites, confirming CLN6's role in lysosomal enzyme trafficking; CLN6-deficient neurons also show increased Golgi area, consistent with impaired ER-to-Golgi transfer of lysosomal enzymes. |
IPSC differentiation into neurons, enzyme activity assay (TPP1), immunofluorescence (LAMP1), Golgi morphology analysis |
bioRxivpreprint |
Low |
38352418
|