Heat-shock protein 70 can replace viral protein R of HIV-1 during nuclear import of the viral preintegration complex.
Heat-shock proteins (Hsp's) are a family of molecular chaperones that contribute to protection from environmental stress. In this report, we demonstrate that a member of this family, Hsp70, facilitates nuclear import of HIV-1 preintegration complexes (PICs). The mechanism of this activity appears to be similar to the one used by Vpr, an HIV-1 protein regulating viral nuclear import and replication in macrophages. Indeed Hsp70 stimulated binding of HIV-1 matrix antigen to GST-karyopherin alpha fusion protein and rescued nuclear import of a Vpr-defective HIV-1 strain in vitro. Binding studies with truncated forms of GST-karyopherin alpha demonstrated that both Vpr and Hsp70 bind to a region in the amino-terminal part of the karyopherin alpha molecule. This region appears to be distinct from the binding sites for two other karyopherin alpha cargoes, basic-type NLS-containing proteins and transcription factor STAT-1. Vpr competed with Hsp70 for binding to karyopherin alpha. These results suggest the presence of a novel regulatory site on karyopherin alpha which is used by Hsp70 and Vpr to stimulate interaction between the HIV-1 PIC and karyopherin alpha and thus promote viral nuclear import.
Agostini
I
I
The Picower Institute for Medical Research, Manhasset, New York 11030, USA.
Popov
S
S
Li
J
J
Dubrovsky
L
L
Hao
T
T
Bukrinsky
M
M
D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D001665:Binding Sites / Q000502:physiology; D001667:Binding, Competitive / Q000502:physiology; D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism / Q000821:virology; D003600:Cytosol / Q000378:metabolism / Q000821:virology; D004268:DNA-Binding Proteins / Q000378:metabolism; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D015658:HIV Infections / Q000378:metabolism* / Q000821:virology*; D015497:HIV-1 / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000166:cytology; D016296:Mutagenesis / Q000502:physiology; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D016662:Virus Integration / Q000502:physiology*; D014779:Virus Replication; D028901:alpha Karyopherins; D054325:vpr Gene Products, Human Immunodeficiency Virus
D000952:Antigens, Polyomavirus Transforming; D004268:DNA-Binding Proteins; D016336:Gene Products, vpr; D018840:HSP70 Heat-Shock Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D015534:Trans-Activators; D028901:alpha Karyopherins; D054325:vpr Gene Products, Human Immunodeficiency Virus