iTRAQ reporter ion regions of phosphopeptide MS/MS spectra (p-value < 0.05). The labeling of post-mortem brain samples was as follows: control 113.11, 114.11, 115.11, 116.11; HIV 117.11, 118.11; and HIV-encephalitis 119.11, 121.12. * This sequence is termed as a KSP repeat and is found four times on the protein between residues 615-625, 628-638, 641-651, and 654-664.