Abstract
Human immunodeficiency virus type 1 (HIV-1) recruits diverse cellular factors into viral particles during its morphogenesis, which apparently play roles in modulating its infectivity. In our study, proteomic techniques demonstrated that a key glycolytic protein, pyruvate kinase muscle type 2 (PKM2), is incorporated into viral particles. Here, we show that virion-packaged PKM2 significantly reduces viral infectivity by affecting the incorporation level of a cellular tRNALys3 into virions. Enhanced expression of PKM2 in HIV-1-producing cells led to a higher incorporation level of PKM2 into progeny virions without affecting the viral maturation process. Compared with the control virus, the high-level-PKM2-packaging virus showed decreased levels of both reverse transcription products and cellular tRNALys3 packaging, suggesting that the shortage of intravirion tRNALys3 suppresses reverse transcription efficiency in target cells. Interestingly, the enhanced expression of PKM2 also suppressed the virion recruitment of other nonpriming cellular tRNAs such as tRNALys1,2 and tRNAAsn, which are known to be selectively packaged into virions, without affecting the steady level of the cytoplasmic pool of those tRNAs in producer cells, suggesting that PKM2 specifically impedes the selective incorporation of tRNAs into virions. Taken together, our findings indicate that PKM2 is a vital host factor that negatively affects HIV-1 infectivity by targeting the tRNALys3-mediated initiation of reverse transcription in target cells.
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