Most tripartite motif (TRIM) family
proteins are critical components of the autophagy machinery and play important roles in host defense against viral pathogens in mammals. However, the roles of
TRIM proteins in autophagy and
viral infection have not been studied in lower invertebrates, especially crustaceans. In this study, we first identified a TRIM50-like gene from Penaeus monodon (designated PmTRIM50-like), which, after a white spot syndrome virus (WSSV) challenge, was significantly upregulated at the
mRNA and
protein levels in the intestine and hemocytes. Knockdown of PmTRIM50-like led to an increase in the WSSV quantity in shrimp, while its overexpression led to a decrease compared with the controls. Autophagy can be induced by WSSV or
rapamycin challenge and has been shown to play a positive role in restricting WSSV replication in P. monodon. The
mRNA and
protein expression levels of PmTRIM50-like significantly increased with the enhancement of
rapamycin-induced autophagy. The autophagy activity induced by WSSV or
rapamycin challenge could be inhibited by silencing PmTRIM50-like in shrimp. Further studies showed that rapamycin failed to induce autophagy or inhibit WSSV replication after knockdown of PmTRIM50-like. Moreover, pull-down and in vitro ubiquitination assays demonstrated that PmTRIM50-like could interact with WSSV envelope
proteins and target them for ubiquitination in vitro. Collectively, this study demonstrated that PmTRIM50-like is required for autophagy and is involved in restricting the proliferation of WSSV through its ubiquitination. This is the first study to report the role of a TRIM family
protein in
virus infection and host autophagy in crustaceans.