Dr. Éric A. Cohen, Director of the Human Retrovirology research unit at the Institut de recherches cliniques de Montréal (IRCM), and his team published yesterday, in the online open-access journal PLos Pathogens, the results of their most recent research on the role of the Vpr protein in HIV (human immunodeficiency virus) infection and AIDS (acquired autoimmune deficiency syndrome).
"We previously identified that HIV, when infecting target cells, blocks cell division and induces cell death," says Dr. Cohen. "We then discovered that the Vpr protein was involved in this process."
HIV-1 encodes several proteins, including the viral protein R (Vpr), which plays an important role in the development of acquired immunodeficiency syndrome (AIDS). Vpr blocks normal cell division, a process believed to increase viral replication and to trigger immune cell death. The researchers recently showed that Vpr performs this activity by interacting with a cellular protein complex (E3 ligase) involved in ubiquitination. Ubiquitination is characterized by the conjugation of a small protein called ubiquitin to various other proteins to regulate their degradation or activities. They also demonstrated that Vpr engages this protein complex to ubiquitinate a yet to be discovered host factor, whose degradation triggers the arrest of cell division.