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Masucci, M. G.

Publications and source records attributed to Masucci, M. G..

2 recordsLinked to original sources

Inhibition of selective autophagy by members of the herpesvirus ubiquitin-deconjugase family

Autophagy is an important component of the innate immune response that restricts infection by different types of pathogens. Viruses have developed multiple strategies to avoid autophagy to complete their replication cycle and promote spreading to new hosts. Here we report that the ubiquitin deconjugases encoded in the N-terminal domain of the large tegument proteins of Epstein-Barr virus (EBV), Kaposi Sarcoma herpesvirus (KSHV) and human cytomegalovirus (HCMV), but not herpes simplex virus-1 (HSV-1), regulate selective autophagy by inhibiting the activity of the autophagy receptor SQSTM1/p62. We found that all the homologs bind to and deubiquitinate SQSTM1/p62 but with variable efficiency, which correlates with their capacity to prevent the colocalization of LC3 with SQSTM1/p62 aggregates and promote the accumulation of a model autophagy substrate. The findings highlight important differences in the strategies by which herpesviruses interfere with selective autophagy.

cell biology

The Epstein-Barr virus ubiquitin deconjugase BPLF1 regulates the activity of Topoisomerase II during virus replication

Topoisomerases are essential for the replication of herpesviruses but the mechanisms by which the viruses hijack the cellular enzymes are largely unknown. We found that topoisomerase-II (TOP2) is a substrate of the Epstein-Barr virus (EBV) ubiquitin deconjugase BPLF1. BPLF1 selectively inhibited the ubiquitination of TOP2 following treatment with topoisomerase poisons, interacted with TOP2 and TOP2{beta} in co-immunoprecipitation and in vitro pull-down, stabilized Etoposide-trapped TOP2 cleavage complexes (TOP2cc) and promoted TOP2 SUMOylation, which halted the DNA-damage response and reduced Etoposide toxicity. Induction of the productive virus cycle promoted the accumulation of TOP2{beta}cc, enhanced TOP2{beta} SUMOylation, and reduced Etoposide toxicity in lymphoblastoid cell lines carrying recombinant EBV encoding the active enzyme. Attenuation of this phenotype upon expression of a catalytic mutant BPLF1-C61A impaired viral DNA synthesis and virus release. These findings highlight a previously unrecognized function of BPLF1 in promoting non-proteolytic pathways for TOP2cc debulking that favor cell survival and virus production.

microbiology