Rho-Associated Coiled-Coil Kinase 1 Translocates to the Nucleus and Inhibits Human Cytomegalovirus Propagation

Abstract

Rho-associated coiled-coil kinase (ROCK) protein is a central kinase that regulates numerous cellular functions, including cellular polarity, motility, proliferation, and apoptosis. Here, we demonstrate that ROCK has antiviral properties, and inhibition of its activity results in enhanced propagation of human cytomegalovirus (HCMV). We show that during HCMV infection, ROCK1 translocates to the nucleus and concentrates in the nucleolus, where it colocalizes with the stress-related chaperone heat shock cognate 71-kDa protein (Hsc70). Gene expression measurements show that inhibition of ROCK activity does not seem to affect the cellular stress response. We demonstrate that inhibition of myosin, one of the central targets of ROCK, also increases HCMV propagation, implying that the antiviral activity of ROCK might be mediated by activation of the actomyosin network. Finally, we demonstrate that inhibition of ROCK results in increased levels of the tegument protein UL32 and of viral DNA in the cytoplasm, suggesting ROCK activity hinders the efficient egress of HCMV particles out of the nucleus. Altogether, our findings illustrate ROCK activity restricts HCMV propagation and suggest this inhibitory effect may be mediated by suppression of capsid egress out of the nucleus. IMPORTANCE ROCK is a central kinase in cells that regulates numerous cellular functions, including cellular polarity, motility, proliferation, and apoptosis. Here we reveal a novel antiviral activity of ROCK during infection with HCMV, a prevalent pathogen infecting most of the population worldwide. We reveal ROCK1 is translocated to the nucleus, where it mainly localizes to the nucleolus. Our findings suggest that ROCK’s antiviral activity may be related to activation of the actomyosin network and inhibition of capsid egress out of the nucleus.

TRANSPIRE: A Computational Pipeline to Elucidate Intracellular Protein Movements from Spatial Proteomics Data Sets

“…Given that DAPK3 is a downstream substrate of ROCK 114 that positively regulates Wnt signaling, 111 it is tempting to speculate that nuclear translocation of DAPK3 contributes to this HCMV-induced increase in Wnt signaling. In support of this notion, ROCK activation has been shown to restrict HCMV propagation, 115 and ROCK is known to phosphorylate DAPK3 at a site that inhibits its nuclear localization. 114 Given our findings, it is possible that the plasma membrane to cytoplasm and nucleus translocation of DAPK3 represents a missing link in HCMV induction of Wnt signaling.…”

Rock1 is a novel host dependency factor of human enterovirus A71: Implication as a drug target

“…Interestingly, siRNA depletion of Rock1, but not Rock2, significantly reduced EV‐A71 replication in both cell lysates and supernatant, indicating that Rock1 is a potential host factor involved in EV‐A71 replication (Figure 5). Notably, previous studies have shown that Rock1, which mainly localizes to the nucleolus, is translocated to the nucleus during human cytomegalovirus infection 46 . The results suggest that antiviral activity of Rock1 in EV‐A71 infection may be associated with activation of the actomyosin network and inhibition of capsid egress out of the nucleus.…”

Antagonistic fungal enterotoxins intersect at multiple levels with host innate immune defences

“…Among the other candidate DcEntB interactors that are predicted by NoD NoLS predictor [ 33 ] to be nucleolar proteins ( S5 Table ), PES-7/IQGAP, LET-60/HRas, RAB-6.1/RAB6A and CDC-42/CDC42 all have GTP binding or GTPase activity. Interestingly, the homologue of LET-502, the Rho-associated coiled-coil kinase, ROCK1, was recently shown to concentrate in the nucleolus during human cytomegalovirus infection [ 83 ]. Whether these different candidates are authentic interactors of DcEntB remains, however, to be established.…”