Dataset Information

The Hypervariable Amino-Terminus of P1 Protease Modulates Potyviral Replication and Host Defense Responses

ABSTRACT: The replication of many RNA viruses involves the translation of polyproteins, whose processing by endopeptidases is a critical step for the release of functional subunits. P1 is the first protease encoded in plant potyvirus genomes; once activated by an as-yet-unknown host factor, it acts in cis on its own C-terminal end, hydrolyzing the P1-HCPro junction. Earlier research suggests that P1 cooperates with HCPro to inhibit host RNA silencing defenses. Using Plum pox virus as a model, we show that although P1 does not have a major direct role in RNA silencing suppression, it can indeed modulate HCPro function by its self-cleavage activity. To study P1 protease regulation, we used bioinformatic analysis and in vitro activity experiments to map the core C-terminal catalytic domain. We present evidence that the hypervariable region that precedes the protease domain is predicted as intrinsically disordered, and that it behaves as a negative regulator of P1 proteolytic activity in in vitro cleavage assays. In viral infections, removal of the P1 protease antagonistic regulator is associated with greater symptom severity, induction of salicylate-dependent pathogenesis-related proteins, and reduced viral loads. We suggest that fine modulation of a viral protease activity has evolved to keep viral amplification below host-detrimental levels, and thus to maintain higher long-term replicative capacity.

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Nicotiana Benthamiana

TISSUE(S): Leaf

SUBMITTER: Sergio Ciordia

LAB HEAD: Juan Antonio García

PROVIDER: PXD017769 | Pride | 2020-08-11

REPOSITORIES: Pride

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Publications

The hypervariable amino-terminus of P1 protease modulates potyviral replication and host defense responses.

Pasin Fabio F Simón-Mateo Carmen C García Juan Antonio JA

PLoS pathogens 20140306 3

The replication of many RNA viruses involves the translation of polyproteins, whose processing by endopeptidases is a critical step for the release of functional subunits. P1 is the first protease encoded in plant potyvirus genomes; once activated by an as-yet-unknown host factor, it acts in cis on its own C-terminal end, hydrolyzing the P1-HCPro junction. Earlier research suggests that P1 cooperates with HCPro to inhibit host RNA silencing defenses. Using Plum pox virus as a model, we show that ...[more]

PMID: 24603811

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Project description:Fruit ripening is a very important physiological process which gains relevance in crop species due to their economical and nutritional repercussions. During fruit ripening enormous metabolic changes occur in a genetically-controlled scenario affecting the physiology of most cell compartments. Peroxisomes are single-membrane bounded organelles present in all eukaryotes which display a noteworthy nitro-oxidative metabolism, and harbor catalase as one of the major antioxidant enzymes in cells. Quantitative proteomics analysis by isobaric tags for relative and absolute quantification (iTRAQ) was used to investigate the ripening process in sweet pepper (Capsicum annuum L.) fruits. Out of 2,574 quantified proteins, 692 were found to be significantly more abundant in immature green fruits compared to red ones, but 497 showed a lower expression as the ripening proceeded. Overall, about 50% of the detectable proteins were estimated to modify their expression due to the ripening process. Data obtained from the Gene Ontology algorithms (AgriGO platform) showed that from all the identified proteins, 46 (2%) were only predicted to have a peroxisomal origin, with a high number of them displaying up-expression tendency during ripening. Catalase was framed within the group which showed lower expression in ripe fruits, but this enzyme was also susceptible to undergo posttranslational modifications (PTMs) promoted by reactive nitrogen and oxygen species (RNS and ROS) through nitration, S-nitrosylation and oxidation events which provoked its inhibition. The biochemical characterization of catalase indicates that it has atypical native molecular mass (125-135 kDa), since it behaves as a homodimer, and isoelectric point of 7.4, which is higher than that of the majority of plant catalases reported so far. Taking together, these data suggest that ROS and RNS could be essential to modulate the role of catalase for the maintenance of basic cellular peroxisomal functions during pepper fruit ripening where nitro-oxidative stress occur.

Dataset Information

The Hypervariable Amino-Terminus of P1 Protease Modulates Potyviral Replication and Host Defense Responses

Publications

The hypervariable amino-terminus of P1 protease modulates potyviral replication and host defense responses.

Similar Datasets

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