PIM1 and PIM3 Kinases Suppress HIV-1 Protein Expression and Particle Production Through Distinct Roles

Area of Science:

• Virology
• Molecular Biology
• Biochemistry

Background:

• PIM kinases (PIM1, PIM2, PIM3) are serine/threonine kinases involved in viral infections.
• Their specific roles in Human Immunodeficiency Virus type 1 (HIV-1) gene expression and particle production are not well understood.

Purpose of the Study:

• To investigate the impact of PIM kinases on HIV-1 and related lentiviral gene expression and virion production.
• To elucidate the specific mechanisms and stages of viral replication affected by PIM kinases.

Main Methods:

• Co-transfection systems were used to study the effects of PIM kinases on HIV-1 and related viruses.
• Kinase-dead mutants were employed to confirm the requirement of catalytic activity.
• Analysis of viral transcription, protein expression, and virion production was performed.

Main Results:

• PIM1 and PIM3 significantly suppressed HIV-1 virion production, while PIM2 had no significant effect.
• This suppression was observed across different HIV-1 clones and other lentiviruses like SIV.
• PIM1 inhibited HIV-1 transcription, whereas PIM3 acted post-transcriptionally to reduce viral protein expression.
• Co-expression of PIM1 and PIM3 showed enhanced suppression, indicating complementary functions.
• Both kinases inhibited expression from non-LTR promoters, suggesting involvement of cellular factors.

Conclusions:

• PIM1 and PIM3 possess distinct and cooperative functions in limiting HIV-1 particle production.
• PIM kinases represent novel host factors that regulate lentiviral gene expression and replication.
• These findings offer new insights into host kinase-mediated control of viral processes.