title: Sequence requirements for Hid binding and apoptosis regulation in the baculovirus inhibitor of apoptosis Op-IAP. Hid binds Op-IAP in a manner similar to Smac binding of XIAP.
abstract: It has been suggested that the Drosophila Hid protein interacts with the baculovirus Op-IAP protein in a manner similar to that of human Smac binding to XIAP, based largely on amino acid sequence homology. However, there is little direct experimental evidence in support of this hypothesis; indeed, evidence exists from previous studies suggesting that the mode of binding is not similar. We have now precisely mapped the interaction between Hid and Op-IAP, and we show clearly for the first time that the biochemical interactions between the amino terminus of Hid and BIR2 of Op-IAP are highly similar to those found between the processed amino terminus of Smac and BIR3 of XIAP. Also similar to Smac, the amino terminus of Hid must be processed to bind Op-IAP. In addition, our data also suggest that a second interaction between Hid and Op-IAP exists that does not involve the amino terminus of Hid, which may explain some of the earlier contradictory results. The evolutionary conservation of this mechanism of binding underscores its importance in apoptotic regulation. Nevertheless, interaction with Hid is not sufficient for Op-IAP to inhibit apoptosis induced by Hid overexpression or by treatment with actinomycin D, indicating that additional sequence elements are required for the anti-apoptotic function of Op-IAP.
authors.affiliation: Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: Casey W
authors.initials: CW
authors.lastname: Wright
authors.forename: Rollie J
authors.initials: RJ
authors.lastname: Clem
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D016367:Baculoviridae / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D003609:Dactinomycin / Q000494:pharmacology; D029721:Drosophila Proteins; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D019476:Insect Proteins / Q000737:chemistry*; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009479:Neuropeptides / Q000737:chemistry* / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014764:Viral Proteins / Q000737:chemistry*; D051636:X-Linked Inhibitor of Apoptosis Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; C412403:DIABLO protein, human; D029721:Drosophila Proteins; C108880:HID protein, Drosophila; D051034:Inhibitor of Apoptosis Proteins; D019476:Insect Proteins; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D009479:Neuropeptides; D010455:Peptides; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D014764:Viral Proteins; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus; D003609:Dactinomycin