title: A 220-kDa activator complex of the 26 S proteasome in insects and humans. A role in type II programmed insect muscle cell death and cross-activation of proteasomes from different species.
abstract: The S10b (SUG2) ATPase cDNA has been cloned by reverse transcription-polymerase chain reaction/rapid amplification of cDNA ends from mRNA of intersegmental muscles of the tobacco horn moth (Manduca sexta). The S10b ATPase is a component of the 26 S proteasome, and its concentration and that of its mRNA increase dramatically during development in a manner similar to other ATPases of the 19 S regulator of the 26 S proteasome. The S10b and S6' (TBP1) ATPases are also present in a complex of approximately 220 kDa in intersegmental muscles. The 220-kDa complex markedly activates (2-10-fold) the 26 S proteasome, even when bound to anti-S10b antibodies immobilized on Sepharose, and increases in concentration approximately 5-fold like the 26 S proteasome in the intersegmental muscles in preparation for the programmed death of the muscle cells. A similar activator complex is present in human brain and placenta. Free activator complexes cross-activate: the Manduca complex activates rat skeletal muscle 26 S proteasomes, and the placental complex activates Manduca 26 S proteasomes. The placental activator complex contains S10b and S6', but not p27. This 220-kDa activator complex has been evolutionarily conserved between species from insect to man and may have a fundamental role in proteasome regulation.
authors.affiliation: Laboratory for Intracellular Proteolysis, Molecular and Cellular Biology Section, School of Biomedical Sciences, Faculty of Medicine, University of Nottingham Medical School, Clifton Boulevard, Nottingham NG7 2UH, United Kingdom.
authors.forename: R A
authors.initials: RA
authors.lastname: Hastings
authors.forename: I
authors.initials: I
authors.lastname: Eyheralde
authors.forename: S P
authors.initials: SP
authors.lastname: Dawson
authors.forename: G
authors.initials: G
authors.lastname: Walker
authors.forename: S E
authors.initials: SE
authors.lastname: Reynolds
authors.forename: M A
authors.initials: MA
authors.lastname: Billett
authors.forename: R J
authors.initials: RJ
authors.lastname: Mayer
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D004789:Enzyme Activation; D006801:Humans; D018402:Manduca; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D010447:Peptide Hydrolases / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D051381:Rats; D013045:Species Specificity
chemical_list: D018076:DNA, Complementary; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D000251:Adenosine Triphosphatases