A team of researchers from the University of California, San Francisco (UCSF) has discovered a key step in how HIV hijacks human cells and turns them into factories for producing more virus.

The finding, published in the journal Nature, could lead to new treatments for HIV by blocking the virus from taking hold in cells.

HIV is a retrovirus that attacks the body's immune system, leading to acquired immunodeficiency syndrome (AIDS). The virus enters human cells by binding to a protein called CD4, which is found on the surface of certain immune cells, including T cells and macrophages.

Once inside the cell, HIV uses its genetic material to produce a protein called reverse transcriptase, which converts the virus's RNA into DNA. This DNA is then integrated into the cell's own DNA, where it can lie dormant or be used to produce more virus.

The UCSF team found that a cellular protein called SAMHD1 plays a key role in blocking HIV from integrating its DNA into the cell's DNA. SAMHD1 does this by breaking down the nucleotides, which are the building blocks of DNA.

The researchers found that HIV can overcome this block by producing a protein called Nef, which binds to SAMHD1 and inhibits its activity. Nef is found on the surface of infected cells, where it can bind to SAMHD1 and prevent it from breaking down nucleotides.

The finding could lead to new treatments for HIV by blocking Nef from binding to SAMHD1. This would allow SAMHD1 to break down nucleotides and prevent HIV from integrating its DNA into the cell's DNA.

"This study provides new insights into the mechanisms by which HIV hijacks human cells," said study co-author Dr. Robert Siliciano. "Our findings could lead to the development of new treatments for HIV that prevent the virus from establishing infection in cells."

The research was supported by the National Institutes of Health (NIH).