Human brain phosphoproteome analyzed by refined phosphopeptide enrichment and high resolution LC-MS/MS

ABSTRACT: Alzheimer’s disease (AD) is the most common form of dementia, characterized by progressive loss of cognitive function. One of the pathological hallmarks of AD is the formation of neurofibrillary tangles composed of abnormally hyperphosphorylated tau protein, but global deregulation of protein phosphorylation in AD is not well analyzed. Here we report a pilot investigation of AD phosphoproteome by titanium dioxide enrichment coupled with high resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS). During the optimization of the enrichment method, we found that phosphate ion at a low concentration (e.g. 1 mM) worked efficiently as a non-phosphopeptide competitor to reduce background. The procedure was further tuned with respect to peptide-to-bead ratio, phosphopeptide recovery and purity. Using this refined method and 9 h LC-MS/MS, we analyzed phosphoproteome in one milligram of digested AD brain lysate, identifying 5,243 phosphopeptides containing 3,717 non-redundant phosphorylation sites on 1,455 proteins. This modified enrichment method is simple and highly efficient. The AD case study demonstrates its feasibility of dissecting phosphoproteome in a limited amount of postmortem human brain.

REANALYSED by: PAe005247

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Brain

SUBMITTER: xusheng wang  

LAB HEAD: Junmin Peng

PROVIDER: PXD001180 | Pride | 2015-01-28

REPOSITORIES: Pride