RING-H2 protein WSSV249 from white spot syndrome virus sequesters a shrimp ubiquitin-conjugating enzyme, PvUbc, for viral pathogenesis.
Modification of proteins by ubiquitin is essential for numerous cellular processes. The RING-H2 finger motif has been implicated in ubiquitin-conjugating enzyme (E2)-dependent ubiquitination. Four proteins, WSSV199, WSSV222, WSSV249, and WSSV403, from white spot syndrome virus (WSSV) contain the RING-H2 motif. Here we report that WSSV249 physically interacts with a shrimp ubiquitin-conjugating enzyme, PvUbc, and mediates ubiquitination through its RING-H2 motif in the presence of E1 and PvUbc. Mutations of the putative zinc coordination residues in the RING-H2 domain of WSSV249, however, ablate ubiquitination efficiency. In addition, the RING-H2 domain of WSSV249 is capable of ubiquitination with UbcH1, UbcH2, UbcH5a, UbcH5b, UbcH5c, UbcH6, and UbcH10, respectively, exhibiting a low degree of E2 specificity. Significantly, the expression of WSSV249 and PvUbc increased during infection, as revealed by real-time PCR. Furthermore, in situ hybridization showed that WSSV249 and PvUbc display similar expression patterns in infected shrimps, and immunofluorescence and immunohistochemistry assays showed an increase of PvUbc in infected shrimp cells. These results suggest that the RING-H2 protein WSSV249 from WSSV may function as an E3 ligase via sequestration of PvUbc for viral pathogenesis in shrimp.
Wang
Zhilong
Z
Animal Health Biotechnology Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
Chua
Hui Kheng
HK
Gusti
Ayu A R A
AA
He
Fang
F
Fenner
Beau
B
Manopo
Ivanus
I
Wang
Hai
H
Kwang
Jimmy
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000201:enzymology* / Q000821:virology*; D014158:Transcription, Genetic; D025801:Ubiquitin / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D046848:White spot syndrome virus 1 / Q000737:chemistry / Q000472:pathogenicity*
D025801:Ubiquitin; D014764:Viral Proteins; D044763:Ubiquitin-Conjugating Enzymes