The following text describes a protein:
Function:
Main component of the apoptosome, an adapter protein complex that mediates activation of the caspase cascade in programmed cell death initiated by the intrinsic apoptosis pathway. Recruits the initiator caspase Dronc, promoting its autocatalytic cleavage and activation; triggers the caspase cascade upstream of the effector caspases Drice and dcp-1. Effector of reaper, grim and hid induced cell killing. Produces at least two isoforms that may activate distinct caspases by separate pathways. Nucleotide binding protein with strong specificity for dATP; dATP binding is not essential, but promotes homooligomerization to form the apoptosome complex. There is currently no evidence of dATPase activity and structural analysis of the nucleotide binding pocket suggests negligible to no dATPase activity (Probable). Caspase activation by the apoptosome was initially thought to be dependent on binding of cytochrome c released from mitochondria, as is the case for vertebrate orthologs. Apoptosis induction by the Dark apoptosome appears to be cytochrome c independent. Required for stress-induced apoptosis, for example in response to radiation (UV or gamma) or treatment with macromolecular synthesis inhibitors like cycloheximide and actinomycin D. Required for most, but not all programmed cell death during embryonic development. Involved in developmental cell number regulation by apoptosis, particularly during neuronal and sensory organ development. Involved in reduction of midline glial cell numbers by programmed cell death during embryogenesis. During metamorphosis involved in removal of larval salivary glands by programmed cell death, but not of the larval midgut.
Domain:
Possesses an N-terminal caspase activation and recruitment domain (CARD). At high protein concentrations in vitro the CARD domain mediates the interaction of two octomeric apoptosome rings to form a double ring structure; Possesses a NB-ARC domain (nucleotide-binding adapter shared by APAF-1, certain R gene products and CED-4) that forms the inner hub of the apoptosome ring and is the main mediator of oligomerization. The interface of the NB-ARC domain and a neighboring helical region forms a binding pocket that can accommodate a nucleotide tri-phosphate with specificity for dATP. In its monomeric non-activated state the binding pocket may be associated with ADP; [Isoform B]: May possess 15 tandem WD repeats that form two C-terminal beta-propellor domains; the smaller beta-propellor may be made up of 7 WD repeats and the larger C-terminal beta-propellor of 8 WD repeats. This region may be involved in regulating caspase activation activity. The WD repeat region does not appear to bind cytochrome c. The WD repeat beta-propellors interact with initiator caspase Dronc; this interaction is not essential for interaction of Dark with Dronc but is required for Dronc-induced assembly of the Dark apoptosome and Dark apoptosome-facilitation of Dronc autocatalytic activation. Interactions between the WD repeat beta-propellor domains and the NB-ARC domain help maintain the monomeric non-active state.
Sequence:
MDFETGEHQYQYKDILSVFEDAFVDNFDCKDVQDMPKSILSKEEIDHIIMSKDAVSGTLRLFWTLLSKQEEMVQKFVEEVLRINYKFLMSPIKTEQRQPSMMTRMYIEQRDRLYNDNQVFAKYNVSRLQPYLKLRQALLELRPAKNVLIDGVLGSGKTWVALDVCLSYKVQCKMDFKIFWLNLKNCNSPETVLEMLQKLLYQIDPNWTSRSDHSSNIKLRIHSIQAELRRLLKSKPYENCLLVLLNVQNAKAWNAFNLSCKILLTTRFKQVTDFLSAATTTHISLDHHSMTLTPDEVKSLLLKYLDCRPQDLPREVLTTNPRRLSIIAESIRDGLATWDNWKHVNCDKLTTIIESSLNVLEPAEYRKMFDRLSVFPPSAHIPTILLSLIWFDVIKSDVMVVVNKLHKYSLVEKQPKESTISIPSIYLELKVKLENEYALHRSIVDHYNIPKTFDSDDLIPPYLDQYFYSHIGHHLKNIEHPERMTLFRMVFLDFRFLEQKIRHDSTAWNASGSILNTLQQLKFYKPYICDNDPKYERLVNAILDFLPKIEENLICSKYTDLLRIALMAEDEAIFEEAHKQVQRFDDRVWFTNHGRFHQHRQIINLGDNEGRHAVYLHNDFCLIALASGQILLTDVSLEGEDTYLLRDESDSSDILRMAVFNQQKHLITLHCNGSVKLWSLWPDCPGRRHSGGSKQQLVNSVVKRFIGSYANLKIVAFYLNEDAGLPEANIQLHVAFINGDVSILNWDEQDQEFKLSHVPVLKTMQSGIRCFVQVLKRYYVVCTSNCTLTVWDLTNGSSNTLELHVFNVENDTPLALDVFDERSKTATVLLIFKYSVWRLNFLPGLSVSLQSEAVQLPEGSFITCGKRSTDGRYLLLGTSEGLIVYDLKISDPVLRSNVSEHIECVDIYELFDPVYKYIVLCGAKGKQVVHVHTLRSVSGSNSHQNREIAWVHSADEISVMTKACLEPNVYLRSLMDMTRERTQLLAVDSKERIHLIKPAISRISEWSTITPTHAASNCKINAISAFNDEQIFVGYVDGVIIDVIHDTALPQQFIEEPIDYLKQVSPNILVASAHSAQKTVIFQLEKIDPLQPNDQWPLMMDVSTKYASLQEGQYIILFSDHGVCHLDIANPSAFVKPKDSEEYIVGFDLKNSLLFLAYENNIIDVFRLIFSCNQLRYEQICEEEIAQKAKISYLVATDDGTMLAMGFENGTLELFAVENRKVQLIYSIEEVHEHCIRQLLFSPCKLLLISCAEQLCFWNVTHMRNNQLEREQKRRRSRRHKQHSVTQEDAVDAAPIAADIDVDVTFVADEFHPVNRGTAELWRNKRGNAIRPELLACVKFVGNEARQFFTDAHFSHFYAIDDEGVYYHLQLLELSRLQPPPDPVTLDIANQYEDLKNLRILDSPLMQDSDSEGADVVGNLVLEKNGGVARATPILEEASS