title: Molecular mechanism of the interactions between white spot syndrome virus anti-apoptosis protein AAP-1 (WSSV449) and shrimp effector caspase.
abstract: AAP-1 (WSSV449), an anti-apoptosis protein encoded by white spot syndrome virus (WSSV), blocked apoptosis in insect cells (SF9) induced by Penaeus monodon effector caspase (Pm caspase). Here, to characterize in detail the anti-Pm caspase activity of AAP-1, both proteins were expressed and purified from Escherichia coli and their interactions were assayed in vitro. We found that although AAP-1 could inhibit Pm caspase activity, the inhibition was not as efficient as that of baculovirus anti-apoptosis protein P35. We further confirmed the binding and cleavage of AAP-1 by Pm caspase, and detected three AAP-1 cleavage products. Mutational analysis and protein N-terminal sequencing revealed that whereas both Asp233 and Asp272 residues of AAP-1 are involved in binding and cleavage by Pm caspase, only the Asp272 is involved in Pm caspase inhibition. Asp233, on the other hand, negatively regulates AAP-1's anti-Pm caspase activity. Lastly, AAP-1 homotypically interacts with each other both in vitro and in insect cells.
authors.affiliation: Center for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, No. 2, Pei-Ning Road, Keelung 20224, Taiwan, ROC. jiholeu@ntou.edu.tw
authors.forename: Jiann-Horng
authors.initials: JH
authors.lastname: Leu
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Chen
authors.forename: Ying-Ru
authors.initials: YR
authors.lastname: Lin
authors.forename: Guang-Hsiung
authors.initials: GH
authors.lastname: Kou
authors.forename: Chu-Fang
authors.initials: CF
authors.lastname: Lo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D016367:Baculoviridae; D053470:Caspases, Effector / Q000378:metabolism*; D002460:Cell Line; D004252:DNA Mutational Analysis; D004266:DNA Virus Infections / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000821:virology; D004794:Enzyme Repression; D007313:Insecta; D033542:Pandalidae; D011485:Protein Binding; D014764:Viral Proteins / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics / Q000378:metabolism*; D046848:White spot syndrome virus 1 / Q000472:pathogenicity / Q000502:physiology*
chemical_list: D051017:Apoptosis Regulatory Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C492234:p35 protein, Baculovirus; D053470:Caspases, Effector