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J Virol. 2012 Sep 12. [Epub ahead of print]
The NS1 protein of influenza A virus interacts with cellular processing bodies (P-bodies) and stress granules through RNA-associated protein 55 (RAP55) during virus infection.
Mok BW, Song W, Wang P, Tai H, Chen Y, Zheng M, Wen X, Lau SY, Wu WL, Matsumoto K, Yuen KY, Chen H.
Source
State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology and the Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong SAR, China.
Abstract
The non-structural protein (NS1) of influenza A virus exhibits multiple functions in the virus life cycle. Proteomics screening for cellular proteins which interact with NS1 identified the cellular protein, RAP55, which is one of the components of cellular processing bodies (P-bodies) and stress granules. To verify whether NS1 interacts with cellular P-bodies, interactions between NS1 and RAP55 and other P-body associated proteins (Ago1, Ago2 and DCP1a) were confirmed using co-immunoprecipitation and cellular co-localization assays. Over-expression of RAP55 induces RAP55-associated stress granule formation and suppresses virus replication. Knockdown of RAP55 with siRNA or expression of a dominant negative mutant RAP55 with defective interaction with P-bodies blocks NS1 co-localization to P-bodies in cells. Expression of NS1 inhibits RAP55 expression and formation of RAP55-associated P-bodies/stress granules. Viral nucleoprotein (NP) was found to be targeted to stress granules in the absence of NS1 but localized to P-bodies when NS1 was co-expressed. Restriction of virus replication via P-bodies occurs in the early phases of infection, as the numbers of RAP55-associated P-bodies in cells diminish over the course of virus infection. NS1 interaction with RAP55-associated P-bodies/stress granules is RNA binding associated and mediated via a PKR-interacting viral element. Mutations introduced into either RNA binding sites, namely R38/K41, or PKR interaction sites, namely I123/M124/K126/N127, cause NS1 proteins to lose the ability to interact with RAP55 and to inhibit stress granules. These results reveal an interplay between virus and host during virus replication in which NP is targeted to P-bodies/stress granules, while NS1 counteracts this host restriction mechanism.
PMID:
22973032
[PubMed - as supplied by publisher]
The NS1 protein of influenza A virus interacts with cellular processing bodies (P-bodies) and stress granules through RNA-associated protein 55 (RAP55) during virus infection.
Mok BW, Song W, Wang P, Tai H, Chen Y, Zheng M, Wen X, Lau SY, Wu WL, Matsumoto K, Yuen KY, Chen H.
Source
State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology and the Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong SAR, China.
Abstract
The non-structural protein (NS1) of influenza A virus exhibits multiple functions in the virus life cycle. Proteomics screening for cellular proteins which interact with NS1 identified the cellular protein, RAP55, which is one of the components of cellular processing bodies (P-bodies) and stress granules. To verify whether NS1 interacts with cellular P-bodies, interactions between NS1 and RAP55 and other P-body associated proteins (Ago1, Ago2 and DCP1a) were confirmed using co-immunoprecipitation and cellular co-localization assays. Over-expression of RAP55 induces RAP55-associated stress granule formation and suppresses virus replication. Knockdown of RAP55 with siRNA or expression of a dominant negative mutant RAP55 with defective interaction with P-bodies blocks NS1 co-localization to P-bodies in cells. Expression of NS1 inhibits RAP55 expression and formation of RAP55-associated P-bodies/stress granules. Viral nucleoprotein (NP) was found to be targeted to stress granules in the absence of NS1 but localized to P-bodies when NS1 was co-expressed. Restriction of virus replication via P-bodies occurs in the early phases of infection, as the numbers of RAP55-associated P-bodies in cells diminish over the course of virus infection. NS1 interaction with RAP55-associated P-bodies/stress granules is RNA binding associated and mediated via a PKR-interacting viral element. Mutations introduced into either RNA binding sites, namely R38/K41, or PKR interaction sites, namely I123/M124/K126/N127, cause NS1 proteins to lose the ability to interact with RAP55 and to inhibit stress granules. These results reveal an interplay between virus and host during virus replication in which NP is targeted to P-bodies/stress granules, while NS1 counteracts this host restriction mechanism.
PMID:
22973032
[PubMed - as supplied by publisher]
