Kantamas ApitanyasaiPiti AmparyupWalaiporn CharoensapsriSaengchan SenapinAnchalee TassanakajonChulalongkorn UniversityThailand National Science and Technology Development AgencyMahidol University2018-11-232018-11-232015-11-01Developmental and Comparative Immunology. Vol.53, No.1 (2015), 234-243187900890145305X2-s2.0-84938070953https://repository.li.mahidol.ac.th/handle/20.500.14594/35353© 2015 Elsevier Ltd. The viral responsive protein, PmHHAP, plays an important role in the control of hemocyte homeostasis in shrimps during viral infection. In this study, we further investigate the role of PmHHAP in the regulation of hemocyte apoptosis. RNA interference (RNAi) mediated gene silencing was used to suppress the PmHHAP expression and the change in hemocyte apoptosis was determined in the knockdown shrimp. Within circulating hemocytes, PmHHAP knockdown increased the number of annexin V-positive apoptotic cells and the combined caspase-3/-7 activity and induced the characteristic apoptotic DNA ladder. Furthermore, PmHHAP down-regulation was accompanied by significantly altered expression of apoptosis-related proteins including the effector caspases, PmCaspase and PmCasp. Yeast two-hybrid and co-immunoprecipitation assays showed that PmHHAP binds to the p20 domain of PmCasp. Moreover, the recombinant PmHHAP protein was able to reduce the caspase activity in the actinomycin D-treated hemocyte cells and r. PmCasp-treated hemocyte cells. Taken together, our data indicate that PmHHAP regulates hemocyte homeostasis by inhibits apoptotic cell death through caspase activation.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyImmunology and MicrobiologyArticleSCOPUS10.1016/j.dci.2015.06.004