Two Cellular Protein Kinases, DNA-PK and PKA, Phosphorylate the Adenoviral L4-33K Protein and Have Opposite Effects on L1 Alternative RNA Splicing

Persson, Heidi Törmänen; Aksaas, Anne Kristin; Kvissel, Anne Katrine; Punga, Tanel; Engström, Åke; Skålhegg, Bjørn Steen; Akusjärvi, Göran

doi:10.1371/journal.pone.0031871

Cited by 12 publications

(22 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Ad E4orf3 and E4orf6 proteins were reported to bind DNA-PK and to inhibit viral DNA concatenation and V(D)J recombination, which relies on NHEJ, a repair process regulated by DNA-PK (30). It was also shown that the Ad L4-33K protein associates with the catalytic subunit of DNA-PK (31). L4-33K functions as an alternative splicing factor involved in activating the shift from the earlier-appearing L1-52,55K mRNA to the later L1-IIIa transcript.…”

Section: Discussionmentioning

confidence: 99%

“…Because we found that during Ad infection, DNA-PK was eventually inhibited by E4orf4 (Fig. 3), and as it was reported that DNA-PK was the target of additional Ad proteins besides E4orf4 (30,31), we investigated the effect of DNA-PK inhibition on the efficiency of Ad replication using three different cell lines. First, HeLa cells were infected with dl366* or dl366*ϩE4orf4 virus, in the presence or absence of a DNA-PK inhibitor added at a concentration that efficiently inhibited this enzyme (Fig.…”

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Biphasic Functional Interaction between the Adenovirus E4orf4 Protein and DNA-PK

Nebenzahl-Sharon

Shalata

Sharf

et al. 2019

J Virol

View full text Add to dashboard Cite

The adenovirus (Ad) E4orf4 protein contributes to virus-induced inhibition of the DNA damage response (DDR) by reducing ATM and ATR signaling. Consequently, E4orf4 inhibits DNA repair and sensitizes transformed cells to killing by DNA-damaging drugs. Inhibition of ATM and ATR signaling contributes to the efficiency of virus replication and may provide one explanation for the cancer selectivity of cell death induced by the expression of E4orf4 alone. In this report, we investigate a direct interaction of E4orf4 with the DDR. We show that E4orf4 physically associates with the DNA-dependent protein kinase (DNA-PK), and we demonstrate a biphasic functional interaction between these proteins, wherein DNA-PK is required for ATM and ATR inhibition by E4orf4 earlier during infection but is inhibited by E4orf4 as infection progresses. This biphasic process is accompanied by initial augmentation and a later inhibition of DNA-PK autophosphorylation as well as by colocalization of DNA-PK with early Ad replication centers and distancing of DNA-PK from late replication centers. Moreover, inhibition of DNA-PK improves Ad replication more effectively when a DNA-PK inhibitor is added later rather than earlier during infection. When expressed alone, E4orf4 is recruited to DNA damage sites in a DNA-PK-dependent manner. DNA-PK inhibition reduces the ability of E4orf4 to induce cancer cell death, likely because E4orf4 is prevented from arriving at the damage sites and from inhibiting the DDR. Our results support an important role for the E4orf4 -DNA-PK interaction in Ad replication and in facilitation of E4orf4-induced cancer-selective cell death.IMPORTANCE Several DNA viruses evolved mechanisms to inhibit the cellular DNA damage response (DDR), which acts as an antiviral defense system. We present a novel mechanism by which the adenovirus (Ad) E4orf4 protein inhibits the DDR. E4orf4 interacts with the DNA damage sensor DNA-PK in a biphasic manner. Early during infection, E4orf4 requires DNA-PK activity to inhibit various branches of the DDR, whereas it later inhibits DNA-PK itself. Furthermore, although both E4orf4 and DNA-PK are recruited to virus replication centers (RCs), DNA-PK is later distanced from late-phase RCs. Delayed DNA-PK inhibition greatly contributes to Ad replication efficiency. When E4orf4 is expressed alone, it is recruited to DNA damage sites. Inhibition of DNA-PK prevents both recruitment and the previously reported ability of E4orf4 to kill cancer cells. Our results support an important role for the E4orf4 -DNA-PK interaction in Ad replication and in facilitation of E4orf4-induced cancer-selective cell death.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Biphasic Functional Interaction between the Adenovirus E4orf4 Protein and DNA-PK

Nebenzahl-Sharon

Shalata

Sharf

et al. 2019

J Virol

View full text Add to dashboard Cite

show abstract

“…The Ad L4-33K protein is a virus-encoded alternative RNA splicing factor which activates splicing of Ad late gene transcripts that contain weak 3= splice sites (8). The L4-33K protein may be phosphorylated by two cellular protein kinases: DNA-dependent protein kinase (DNA-PK) and protein kinase A (PKA) (9). L4-33K interacts with the catalytic subunit of DNA-PK, and phosphorylation by DNA-PK has an inhibitory role in L4-33K-mediated alternative RNA splicing.…”

mentioning

confidence: 99%

“…L4-33K interacts with the catalytic subunit of DNA-PK, and phosphorylation by DNA-PK has an inhibitory role in L4-33K-mediated alternative RNA splicing. On the other hand, the phosphorylation of L4-33K by PKA stimulates L4-33K-mediated alternative RNA splicing (9). Through this process, L4-33K is believed to coordinately control late gene expression to optimize the conditions for maximal virus production.…”

mentioning

confidence: 99%

The Adenovirus L4-33K Protein Regulates both Late Gene Expression Patterns and Viral DNA Packaging

Guimet

Hearing

2013

J Virol

View full text Add to dashboard Cite

The adenovirus (Ad) L4-33K protein has been linked to disparate functions during infection. L4-33K is a virus-encoded alternative RNA splicing factor which activates splicing of viral late gene transcripts that contain weak 3= splice sites. Additionally, L4-33K has been indicated to play a role in adenovirus assembly. We generated and characterized an Ad5 L4-33K mutant virus to further explore its function(s) during infection. Infectivity, viral genome replication, and most viral gene expression of the L4-33K mutant virus are comparable to those of the wild-type virus, except for a prominent decrease in the levels of the late proteins IIIa and pVI. The L4-33K mutant virus produces only empty capsids, indicating a defect in viral DNA packaging. We demonstrate that L4-33K does not preferentially bind to viral packaging sequences in vivo, and mutation of L4-33K does not interfere with the binding of the known viral packaging proteins IVa2, L4-22K, L1-52/55K, and IIIa to the packaging sequences in vivo.Collectively, these results demonstrate that the phenotype of an Ad5 L4-33K mutant virus is complex. The L4-33K protein regulates the accumulation of selective Ad late gene mRNAs and is involved in the proper transition of gene expression during the late phase of infection. The L4-33K protein also plays a role in adenovirus morphogenesis by promoting the packaging of the viral genome into the empty capsid. These results demonstrate the multifunctional nature of the L4-33K protein and its involvement in several different and critical aspects of viral infection.

show abstract

“…Another important aspect of genome regulation is alternative splicing. G. Akusjarvi (University of Uppsala, Sweden) showed data to indicate that the late viral splice site regulatory protein L4-33K, which controls alternative splicing of the viral L1 transcript, is phosphorylated by DNA-dependent protein kinase (DNA-PK) and protein kinase A (PKA) (Tormanen Persson et al, 2012). Phosphorylation by DNA-PK inhibits while phosphorylation by PKA enhances L1-IIIa alternative splicing.…”

Section: Transcriptional Regulation and Replicationmentioning

confidence: 99%

Adenoviruses - from pathogens to therapeutics: a report on the 10th International Adenovirus Meeting

et al. 2012

View full text Add to dashboard Cite

Two Cellular Protein Kinases, DNA-PK and PKA, Phosphorylate the Adenoviral L4-33K Protein and Have Opposite Effects on L1 Alternative RNA Splicing

Cited by 12 publications

References 70 publications

Biphasic Functional Interaction between the Adenovirus E4orf4 Protein and DNA-PK

Biphasic Functional Interaction between the Adenovirus E4orf4 Protein and DNA-PK

The Adenovirus L4-33K Protein Regulates both Late Gene Expression Patterns and Viral DNA Packaging

Adenoviruses - from pathogens to therapeutics: a report on the 10th International Adenovirus Meeting

Contact Info

Product

Resources

About