Mutant gammaPKC found in spinocerebellar ataxia type 14 induces aggregate-independent maldevelopment of dendrites in primary cultured Purkinje cells.
Missense mutations in protein kinase Cgamma (gammaPKC) gene have been found in spinocerebellar ataxia type 14 (SCA14), an autosomal dominant neurodegenerative disease. We previously demonstrated that mutant gammaPKC found in SCA14 is susceptible to aggregation and induces apoptosis in cultured cell lines. In the present study, we investigated whether mutant gammaPKC formed aggregates and how mutant gammaPKC affects the morphology and survival of cerebellar Purkinje cells (PCs), which are degenerated in SCA14 patients. Adenovirus-transfected primary cultured PCs expressing mutant gammaPKC-GFP also had aggregates and underwent apoptosis. Long-term time-lapse observation revealed that PCs have a potential to eliminate aggregates of mutant gammaPKC-GFP. Mutant gammaPKC-GFP disturbed the development of PC dendrites and reduced synapse formation, regardless of the presence or absence of its aggregates. In PCs without aggregates, mutant gammaPKC-GFP formed soluble oligomers, resulting in reduced mobility and attenuated translocation of mutant gammaPKC-GFP upon stimulation. These molecular properties of mutant gammaPKC might affect the dendritic morphology in PCs, and be involved in the pathogenesis of SCA14.
Seki
Takahiro
T
Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Shimahara
Takayuki
T
Yamamoto
Kazuhiro
K
Abe
Nana
N
Amano
Taku
T
Adachi
Naoko
N
Takahashi
Hideyuki
H
Kashiwagi
Kaori
K
Saito
Naoaki
N
Sakai
Norio
N
D000818:Animals; D017209:Apoptosis; D002470:Cell Survival; D002478:Cells, Cultured; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure; D049229:Dendritic Spines / Q000502:physiology / Q000648:ultrastructure; D036681:Fluorescence Recovery After Photobleaching; D049452:Green Fluorescent Proteins; D006801:Humans; D051379:Mice; D050505:Mutant Proteins / Q000378:metabolism; D020125:Mutation, Missense; D011493:Protein Kinase C / Q000235:genetics* / Q000378:metabolism*; D011689:Purkinje Cells / Q000502:physiology* / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020754:Spinocerebellar Ataxias / Q000235:genetics; D013569:Synapses / Q000502:physiology; D014162:Transfection
D050505:Mutant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C087857:protein kinase C gamma; D011493:Protein Kinase C