An arginine/lysine-rich motif is crucial for VCP/p97-mediated modulation of ataxin-3 fibrillogenesis.
Arginine/lysine-rich motifs typically function as targeting signals for the translocation of proteins to the nucleus. Here, we demonstrate that such a motif consisting of four basic amino acids in the polyglutamine protein ataxin-3 (Atx-3) serves as a recognition site for the interaction with the molecular chaperone VCP. Through this interaction, VCP modulates the fibrillogenesis of pathogenic forms of Atx-3 in a concentration-dependent manner, with low concentrations of VCP stimulating fibrillogenesis and excess concentrations suppressing it. No such effect was observed with a mutant Atx-3 variant, which does not contain a functional VCP interaction motif. Strikingly, a stretch of four basic amino acids in the ubiquitin chain assembly factor E4B was also discovered to be critical for VCP binding, indicating that arginine/lysine-rich motifs might be generally utilized by VCP for the targeting of proteins. In vivo studies with Drosophila models confirmed that VCP selectively modulates aggregation and neurotoxicity induced by pathogenic Atx-3. Together, these results define the VCP-Atx-3 association as a potential target for therapeutic intervention and suggest that it might influence the progression of spinocerebellar ataxia type 3.
Boeddrich
Annett
A
Department of Neuroproteomics, Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany.
Gaumer
Sébastien
S
Haacke
Annette
A
Tzvetkov
Nikolay
N
Albrecht
Mario
M
Evert
Bernd O
BO
Müller
Eva C
EC
Lurz
Rudi
R
Breuer
Peter
P
Schugardt
Nancy
N
Plassmann
Stephanie
S
Xu
Kexiang
K
Warrick
John M
JM
Suopanki
Jaana
J
Wüllner
Ullrich
U
Frank
Ronald
R
Hartl
Ulrich F
UF
Bonini
Nancy M
NM
Wanker
Erich E
EE
D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine / Q000235:genetics*; D000067699:Ataxin-3; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D019556:COS Cells; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D004330:Drosophila / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D000071058:Huntingtin Protein; D002479:Inclusion Bodies / Q000378:metabolism; D008239:Lysine / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D019913:Nuclear Localization Signals / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism; D011485:Protein Binding; D012097:Repressor Proteins; D017386:Sequence Homology, Amino Acid; D000074405:Valosin Containing Protein
D018797:Cell Cycle Proteins; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D012097:Repressor Proteins; D000255:Adenosine Triphosphate; D001120:Arginine; C092341:ATXN3 protein, human; D000067699:Ataxin-3; D000251:Adenosine Triphosphatases; C000614178:VCP protein, human; D000074405:Valosin Containing Protein; D008239:Lysine