Data were analyzed using the MASCOT 1.9 search engine (Matrix Science) to search against the human (148,148 sequences) MSDB protein database (Release 20063108). Search parameters allowed for one missed tryptic cleavage site, the carbamidomethylation of cysteine, and the possible oxidation of methionine; precursor ion mass tolerance was 150 ppm, and fragment ion mass tolerance was 0.25 Da. All identified proteins have a MASCOT score greater than 64 (the default MASCOT threshold for such searches), corresponding to a statistically significant (p Ͻ 0.05) confident identification.