PmTBC1D20, a Rab GTPase-activating protein from the black tiger shrimp, Penaeus monodon, is involved in white spot syndrome virus infection

TBC (TRE2/BUB2/CDC16) domain proteins contain an ∼200-amino-acid motif and function as Rab GTPase-activating proteins that are required for regulating the activity of Rab proteins, and so, in turn, endocytic membrane trafficking in cells. TBC domain family member 20 (TBC1D20) has recently been reported to mediate Hepatitis C virus replication. Herein, PmTBC1D20 identified from the black tiger shrimp, Penaeus monodon, was characterized and evaluated for its role in white spot syndrome virus (WSSV) infection. The full-length cDNA sequence of PmTBC1D20 contains 2003 bp with a predicted 1443 bp open reading frame encoding a deduced 480 amino acid protein. Its transcript levels were significantly up-regulated at 24 and 48 h by ∼2.3- and 2.1-fold, respectively, after systemic infection with WSSV. In addition, depletion of PmTBC1D20 transcript in shrimps by double stranded RNA interference led to a decrease in the level of transcripts of three WSSV genes (VP28, ie1 and wsv477). This suggests the importance of PmTBC1D20 in WSSV infection. This is the first report of TBC1D20 in a crustacean and reveals the possible mechanism used by WSSV to modulate the activity of the host protein, PmTBC1D20, for its benefit in viral trafficking and replication.