Ubiquitination and cysteine nitrosylation during aging and Alzheimer's disease.
Protein oxidation and ubiquitination of brain proteins are part of mechanisms that modulate protein function or that inactivate proteins and target misfolded proteins to degradation. In this study, we focused on brain aging and on mechanism involved in neurodegeneration such as events occurring in Alzheimer's disease (AD). The goal was to identify differences in nitrosylated proteins - at cysteine residues, and in the composition of ubiquinated proteins between aging and Alzheimer's samples by using a proteomic approach. A polyclonal anti-S-nitrosyl-cysteine, a mono- and a polyclonal anti-ubiquitin antibody were used for the detection of modified or ubiquitinated proteins in middle-aged and aged human entorhinal autopsy brains tissues of 14 subjects without neurological signs and 8 Alzheimer's patients. Proteins were separated by one- and two-dimensional gel electrophoresis and analyzed by Coomassie blue and immuno-blot staining. We identified that the glial fibrillary acidic and tau proteins are more ubiquitinated in brain tissues of Alzheimer's patients. Furthermore, glial fibrillary proteins were also found in nitrosylated state and further characterized by 2D Western blots and identified. Since reactive astrocytes localized prominently around senile plaques one can speculate that elements of plaques such as beta-amyloid proteins may activate surrounding glial elements and proteins.
Center for Psychiatric Neuroscience, Proteomics Unit, CHUV, 1008 Prilly-Lausanne, Switzerland. Irene.Riederer@chuv.ch
Irène M
IM
Riederer
Mariano
M
Schiffrin
Enikö
E
Kövari
Constantin
C
Bouras
Beat M
BM
Riederer
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D000544:Alzheimer Disease / Q000378:metabolism*; D001253:Astrocytes / Q000378:metabolism; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D018728:Entorhinal Cortex / Q000378:metabolism*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D040901:Proteomics; D013194:Staining and Labeling; D054875:Ubiquitination / Q000502:physiology*; D016875:tau Proteins / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; C054369:MAPT protein, human; D016875:tau Proteins