Molecular Characterization of Two Mitogen-Activated Protein Kinases: p38 MAP Kinase and Ribosomal S6 Kinase From Bombyx mori (Lepidoptera: Bombycidae), and Insight Into Their Roles in Response to BmNPV Infection

Muhammad, Azharuddin; Toufeeq, Shahzad; Yu, Hai-Zhong; Wang, Jie; Zhang, Shang-Zhi; Li, Bing; Li, Zhen; Yang, Li-Ang; Hu, Pei; Ma, Yan; Xu, Jia-Ping

Innate immune response is conserved from higher to lower organisms and plays vital role against pathogenic infection (Shahzad et al. 2017) . Previous studies have shown that p38 MAPK triggered inflammatory response and initiated innate immune responses in shrimp . Moreover, some studied also discovered that p38 MAPKs are also initiated during mammalian viral infection and involve in viral replication (Banerjee et al. 2002 , Hirasawa et al. 2003 . Wei et al. (2015) revealed that p38 MAPK involved in virus replication during irridovirus infection. p38 MAPKs from Drosophila mediated host defense against bacteria and fungi, as well as p38 pathway involved in stress response (Chen et al. 2010) . S6K belongs to AGC family of kinases, which are a direct substrate of ERK1/ ERK2 (Tavares et al. 2015) . S6K1 and S6K2, homologous of S6K, have been identified in mammals (Gwalter et al. 2009 ). S6K1 and S6K2 when interact with Kaposi's sarcoma-associated herpesvirus, their kinase activities are increased (Kuang et al. 2008) . The loss of S6K in Drosophila leads to small cell size and body (Montagne et al. 1999) . Evidence suggests that RSK2 participates in innate immune responses, and its knockdown stimulates the growth of influenza virus (Kakugawa et al. 2009 ).