Hip14l-deficient mice develop neuropathological and behavioural features of Huntington disease.
Palmitoylation, the dynamic post-translational addition of the lipid, palmitate, to proteins by Asp-His-His-Cys-containing palmitoyl acyltransferase (PAT) enzymes, modulates protein function and localization and plays a key role in the nervous system. Huntingtin-interacting protein 14 (HIP14), a well-characterized neuronal PAT, has been implicated in the pathogenesis of Huntington disease (HD), a fatal neurodegenerative disease associated with motor, psychiatric and cognitive symptoms, caused by a CAG expansion in the huntingtin gene (HTT). Mice deficient for Hip14 expression develop neuropathological and behavioural features similar to HD, and the catalytic activity of HIP14 is impaired in HD mice, most likely due to the reduced interaction of HIP14 with HTT. Huntingtin-interacting protein 14-like (HIP14L) is a paralog of HIP14, with identical domain structure. Together, HIP14 and HIP14L are the major PATs for HTT. Here, we report the characterization of a Hip14l-deficient mouse model, which develops adult-onset, widespread and progressive neuropathology accompanied by early motor deficits in climbing, impaired motor learning and reduced palmitoylation of a novel HIP14L substrate: SNAP25. Although the phenotype resembles that of the Hip14(-/-) mice, a more progressive phenotype, similar to that of the YAC128 transgenic mouse model of HD, is observed. In addition, HIP14L interacts less with mutant HTT than the wild-type protein, suggesting that reduced HIP14L-dependent palmitoylation of neuronal substrates may contribute to the pathogenesis of HD. Thus, both HIP14 and HIP14L may be dysfunctional in the disease.
Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada.
Liza M
LM
Sutton
Shaun S
SS
Sanders
Stefanie L
SL
Butland
Roshni R
RR
Singaraja
Sonia
S
Franciosi
Amber L
AL
Southwell
Crystal N
CN
Doty
Mandi E
ME
Schmidt
Katherine K N
KK
Mui
Vlad
V
Kovalik
Fiona B
FB
Young
Weining
W
Zhang
Michael R
MR
Hayden
D000217:Acyltransferases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004195:Disease Models, Animal; D005260:Female; D017353:Gene Deletion; D005786:Gene Expression Regulation; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics* / Q000473:pathology; D015151:Immunoblotting; D007858:Learning / Q000502:physiology; D054878:Lipoylation; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D050825:Synaptosomal-Associated Protein 25 / Q000235:genetics / Q000378:metabolism
C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C494209:Snap25 protein, mouse; D050825:Synaptosomal-Associated Protein 25; D000217:Acyltransferases; C569387:Zdhhc17 protein, mouse