Characterization and function of GSK3β from Litopenaeus vannamei in WSSV infection.

GSK3β, a serine/threonine protein kinase, is a crucial regulator in several signaling pathway and plays a vital role in multiple cellular processes including cell proliferation, growth, apoptosis and immune response. In this study, a GSK3β homolog from L. vannamei, designed as LvGSK3β, was characterized. Sequence analysis showed that LvGSK3β possessed a highly similarity with GSK3β from other species, which contained a catalytic domain and serine/threonine phosphorylation sites. To analyze the role of LvGSK3β in the process of white spot syndrome virus (WSSV) infection, real-time quantitative PCR and western blot assays were performed. The results showed that the transcription and expression levels of LvGSK3β were inhibited upon WSSV challenge, accompanied with down-regulated phosphorylation levels. When LvGSK3β was silenced, the transcription of WSSV gene ie1 was inhibited, and the apoptosis of hemocytes induced by WSSV was up-regulated remarkably as well. In addition, inactivation of LvGSK3β could also depress virus infection that further validated the results. Conclusively, LvGSK3β was an important protein for shrimp immunomodulation, and shrimp might promote the apoptosis to restrain WSSV infection by inhibition of LvGSK3β. The study will be helpful for understanding the molecular mechanism of host-virus interaction.