Cellular Proteins Hsp60 and SAHH as Negative Regulators of the Early Stages of HIV-1 Replication

Increasing resistance of human immunodeficiency virus type 1 (HIV-1) to the drugs targeting viral proteins stimulates the search for new therapeutic targets, among which are blockers of virus-host protein interactions. For two cellular proteins (LEDGF/p75 and Ku70) that interact with viral integrase, binding inhibitors have already been identified that reduce replication efficiency. Previously, using the methods of cross-linking and co-immunoprecipitation followed by mass spectrometry, several novel potential cellular partners of HIV-1 integrase were identified, including the Hsp60 chaperonin and S-adenosylhomocysteine hydrolase (SAHH). In the present study, we demonstrate that these purified recombinant proteins co-precipitate in vitro with integrase, indicating their ability to directly interact with the enzyme. Knockdown of Hsp60 and SAHH in the human cells was found to stimulate transduction efficiency by the HIV-1-based pseudovirus. This effect occurs specifically at the early stages of HIV-1 replication, not at the stage of proviral transcription. Furthermore, we were able to determine the stage of HIV-1 replication influenced by these proteins. It was revealed that the Hsp60 knockdown stimulates integration, while the SAHH knockdown enhances efficiency of the viral reverse transcription, in which integrase is also involved.