Altered trafficking of membrane proteins in Purkinje cells of SCA1 transgenic mice

Pamela J. Skinner, Cynthia A. Vierra-Green, H. Brent Clark, Huda Y. Zoghbi, Harry T. Orr

Research output: Contribution to journalArticle

79 Scopus citations

Abstract

Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by the expression of mutant ataxin-1 that contains an expanded polyglutamine tract. Overexpression of mutant ataxin-1 in Purkinje cells of transgenic mice results in a progressive ataxia and Purkinje cell pathology that are very similar to those seen in SCA1 patients. Two prominent aspects of pathology in the SCA1 mice are the presence of cytoplasmic vacuoles and dendritic atrophy. We found that the vacuoles in Purkinje cells seem to originate as large invaginations of the outer cell membrane. The cytoplasmic vacuoles contained proteins from the somatodendritic membrane, including mGluR1, GluRδ1/δ2 GluR2/3, and protein kinase C (PKC) γ. Further examination of PKCγ revealed that its sequestration into cytoplasmic vacuoles was accompanied by concurrent loss of PKCγ localization at the Purkinje cell dendritic membrane and decreased detection of PKCγ by Western blot analysis. In addition, the vacuoles were immunoreactive for components of the ubiquitin/proteasome degradative pathway. These findings present a link between vacuole formation and loss of dendrites in Purkinje cells of SCA1 mice and indicate that altered somatodendritic membrane trafficking and loss of proteins including PKCγ, are a part of the neuronal dysfunction in SCA1 transgenic mice.

Original languageEnglish (US)
Pages (from-to)905-913
Number of pages9
JournalAmerican Journal of Pathology
Volume159
Issue number3
DOIs
StatePublished - 2001

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