Quantitative proteomics analysis of phosphorylated proteins in the hippocampus of Alzheimer's disease subjects

Phosphorylation on tyrosine, threonine and serine residues represents one of the most important post-translational modifications and is a key regulator of cellular signaling of multiple biological processes that require a strict control by protein kinases and protein phosphatases. Abnormal protein phosphorylation has been associated with several human diseases including Alzheimer's disease (AD). One of the characteristic hallmarks of AD is the presence of neurofibrillary tangles, composed of microtubule-associated, abnormally hyperphosphorylated tau protein. However, several others proteins showed altered phosphorylation levels in AD suggesting that deregulated phosphorylation may contribute to AD pathogenesis. Phosphoproteomics has recently gained attention as a valuable approach to analyze protein phosphorylation, both in a quantitative and a qualitative way. We used the fluorescent phosphospecific Pro-Q Diamond dye to identify proteins that showed alterations in their overall phosphorylation in the hippocampus of AD vs. control (CTR) subjects. Significant changes were found for 17 proteins involved in crucial neuronal process such as energy metabolism or signal transduction. These phosphoproteome data may provide new clues to better understand molecular pathways that are deregulated in the pathogenesis and progression of AD.

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► Hippocampal protein phosphorylation levels in Alzheimer's disease (AD) were measured.
► A two-dimensional phosphoproteomics multiplexed approach was used.
► 17 proteins involved in critical neuronal processes had altered phosphorylation.
► Identified proteins are consistent with clinical presentation of AD; and with pathology of AD.
► Identified proteins may have key roles in pathogenesis and progression of AD.