title: ATPgammaS disrupts human immunodeficiency virus type 1 virion core integrity.
abstract: Heat shock protein 70 (Hsp70) is incorporated within the membrane of primate lentiviral virions. Here we demonstrate that Hsp70 is also incorporated into oncoretroviral virions and that it remains associated with membrane-stripped human immunodeficiency virus type 1 (HIV-1) virion cores. To determine if Hsp70 promotes virion infectivity, we attempted to generate Hsp70-deficient virions with gag deletion mutations, Hsp70 transdominant mutants, or RNA interference, but these efforts were confounded, largely because they disrupt virion assembly. Given that polypeptide substrates are bound and released by Hsp70 in an ATP-hydrolytic reaction cycle, we supposed that incubation of HIV-1 virions with ATP would perturb Hsp70 interaction with substrates in the virion and thereby decrease infectivity. Treatment with ATP or ADP had no observable effect, but ATPgammaS and GTPgammaS, nucleotide triphosphate analogues resistant to Hsp70 hydrolysis, dramatically reduced the infectivity of HIV-1 and murine leukemia virus virions. ATPgammaS-treated virions were competent for fusion with susceptible target cells, but viral cDNA synthesis was inhibited to an extent that correlated with the magnitude of decrease in infectivity. Intravirion reverse transcription by HIV-1, simian immunodeficiency virus, or murine leukemia virus was also inhibited by ATPgammaS. The effects of ATPgammaS on HIV-1 reverse transcription appeared to be indirect, resulting from disruption of virion core morphology that was evident by transmission electron microscopy. Consistent with effects on capsid conformation, ATPgammaS-treated viruslike particles failed to saturate host antiviral restriction activity. Our observations support a model in which the catalytic activity of virion-associated Hsp70 is required to maintain structural integrity of the virion core.
authors.affiliation: Department of Microbiology and Medicine, Columbia University, 701 W. 168th Street, New York, NY 10032, USA.
authors.forename: Cagan
authors.initials: C
authors.lastname: Gurer
authors.forename: Anders
authors.initials: A
authors.lastname: Höglund
authors.forename: Stefan
authors.initials: S
authors.lastname: Höglund
authors.forename: Jeremy
authors.initials: J
authors.lastname: Luban
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D017353:Gene Deletion; D015750:Genes, gag / Q000235:genetics; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D015658:HIV Infections / Q000821:virology; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors; D015497:HIV-1 / Q000737:chemistry / Q000472:pathogenicity / Q000502:physiology* / Q000648:ultrastructure; D018840:HSP70 Heat-Shock Proteins / Q000172:deficiency / Q000235:genetics; D006801:Humans; D009052:Leukemia Virus, Murine / Q000737:chemistry* / Q000235:genetics; D051381:Rats; D012192:Retroviridae Infections / Q000821:virology; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology; D014412:Tumor Virus Infections / Q000821:virology; D014771:Virion / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D014774:Virulence; D019065:Virus Assembly
chemical_list: D018840:HSP70 Heat-Shock Proteins; D018894:Reverse Transcriptase Inhibitors; C022571:adenosine 5'-O-(3-thiotriphosphate); D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000255:Adenosine Triphosphate; D054303:HIV Reverse Transcriptase