Functional Analysis of Potential Phosphorylation Sites in the HIV-1 p6 Gag Domain

The human immunodeficiency virus type 1 (HIV-1) interacts with multiple host components and usurps cellular regulatory mechanisms, such as phosphorylation to help direct different events of its replication cycle. Protein phosphorylation is a posttranslational modification widely used by the cell to convey specific messages in response to specific stimuli and allows the coordination of a myriad of cellular processes in a timely and specific manner. The C-terminal p6 domain of the HIV-1 Gag protein, besides carrying the PTAP L-domain required to mediate virus release is subject to phosphorylation. Although p6 has been identified to exist as the major phosphoprotein in HIV-1 particles, an in-depth study of the functional role of p6 phosphorylation has not been conducted to date. Thus, these observations prompted us to perform a comprehensive analysis of the consequences of potential p6 phosphorylation in the HIV-1 replication cycle