Proteomic characterization of lipid raft proteins in amyotrophic lateral sclerosis mouse spinal cord

• Published in: The FEBS journal 2009-06, Vol.276 (12), p.3308-3323
• Main Authors: Zhai, Jianjun, Ström, Anna-Lena, Kilty, Renee, Venkatakrishnan, Priya, White, James, Everson, William V, Smart, Eric J, Zhu, Haining
• Format: Article
• Language: English
• Subjects: Amyotrophic lateral sclerosis; Amyotrophic Lateral Sclerosis - genetics; Amyotrophic Lateral Sclerosis - metabolism; Animals; Biochemistry; Blotting, Western; Cellular biology; Chromatography, Liquid; cytoskeletal dynamics; Electrophoresis, Polyacrylamide Gel; Humans; lipid rafts; Membrane Microdomains - metabolism; Membrane Proteins - analysis; Membrane Proteins - classification; Membrane Proteins - metabolism; Mice; Mice, Transgenic; Models, Biological; Molecular biology; Mutation; Proteins; Proteomics; Proteomics - methods; Rodents; Signal Transduction; Spinal cord; Spinal Cord - metabolism; Superoxide Dismutase - genetics; Superoxide Dismutase-1; Tandem Mass Spectrometry; vesicular trafficking
• ISSN: 1742-464X; 1742-4658; 1742-4658
• DOI: 10.1111/j.1742-4658.2009.07057.x

Familial amyotrophic lateral sclerosis (ALS) has been linked to mutations in the copper/zinc superoxide dismutase (SOD1) gene. The mutant SOD1 protein exhibits a toxic gain-of-function that adversely affects the function of neurons. However, the mechanism by which mutant SOD1 initiates ALS is unclear. Lipid rafts are specialized microdomains of the plasma membrane that act as platforms for the organization and interaction of proteins involved in multiple functions, including vesicular trafficking, neurotransmitter signaling, and cytoskeletal rearrangements. In this article, we report a proteomic analysis using a widely used ALS mouse model to identify differences in spinal cord lipid raft proteomes between mice overexpressing wild-type (WT) and G93A mutant SOD1. In total, 413 and 421 proteins were identified in the lipid rafts isolated from WT and G93A mice, respectively. Further quantitative analysis revealed a consortium of proteins with altered levels between the WT and G93A samples. Functional classification of the 67 altered proteins revealed that the three most affected subsets of proteins were involved in: vesicular transport, and neurotransmitter synthesis and release; cytoskeletal organization and linkage to the plasma membrane; and metabolism. Other protein changes were correlated with alterations in: microglia activation and inflammation; astrocyte and oligodendrocyte function; cell signaling; cellular stress response and apoptosis; and neuronal ion channels and neurotransmitter receptor functions. Changes of selected proteins were independently validated by immunoblotting and immunohistochemistry. The significance of the lipid raft protein changes in motor neuron function and degeneration in ALS is discussed, particularly for proteins involved in vesicular trafficking and neurotransmitter signaling, and the dynamics and regulation of the plasma membrane-anchored cytoskeleton.