HIV-1 Tat protein exits from cells via a leaderless secretory pathway and binds to extracellular matrix-associated heparan sulfate proteoglycans through its basic region

These results demonstrate that Tat exits from intact cells through a leaderless secretion pathway which shares several features with that of acid FGF or bFGF. The released Tat binds to HSPG through its basic region and this determines its storage into the ECM, as occurs for bFGF.