title: OPA1 processing reconstituted in yeast depends on the subunit composition of the m-AAA protease in mitochondria.
abstract: The morphology of mitochondria in mammalian cells is regulated by proteolytic cleavage of OPA1, a dynamin-like GTPase of the mitochondrial inner membrane. The mitochondrial rhomboid protease PARL, and paraplegin, a subunit of the ATP-dependent m-AAA protease, were proposed to be involved in this process. Here, we characterized individual OPA1 isoforms by mass spectrometry, and we reconstituted their processing in yeast to identify proteases involved in OPA1 cleavage. The yeast homologue of OPA1, Mgm1, was processed both by PARL and its yeast homologue Pcp1. Neither of these rhomboid proteases cleaved OPA1. The formation of small OPA1 isoforms was impaired in yeast cells lacking the m-AAA protease subunits Yta10 and Yta12 and was restored upon expression of murine or human m-AAA proteases. OPA1 processing depended on the subunit composition of mammalian m-AAA proteases. Homo-oligomeric m-AAA protease complexes composed of murine Afg3l1, Afg3l2, or human AFG3L2 subunits cleaved OPA1 with higher efficiency than paraplegin-containing m-AAA proteases. OPA1 processing proceeded normally in murine cell lines lacking paraplegin or PARL. Our results provide evidence for different substrate specificities of m-AAA proteases composed of different subunits and reveal a striking evolutionary switch of proteases involved in the proteolytic processing of dynamin-like GTPases in mitochondria.
authors.affiliation: Institute for Physiological Chemistry, Ludwig Maximilians University, 81377 Munich, Germany.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Duvezin-Caubet
authors.forename: Mirko
authors.initials: M
authors.lastname: Koppen
authors.forename: Johannes
authors.initials: J
authors.lastname: Wagener
authors.forename: Michael
authors.initials: M
authors.lastname: Zick
authors.forename: Lars
authors.initials: L
authors.lastname: Israel
authors.forename: Andrea
authors.initials: A
authors.lastname: Bernacchia
authors.forename: Ravi
authors.initials: R
authors.lastname: Jagasia
authors.forename: Elena I
authors.initials: EI
authors.lastname: Rugarli
authors.forename: Axel
authors.initials: A
authors.lastname: Imhof
authors.forename: Walter
authors.initials: W
authors.lastname: Neupert
authors.forename: Thomas
authors.initials: T
authors.lastname: Langer
authors.forename: Andreas S
authors.initials: AS
authors.lastname: Reichert
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000595:Amino Acid Sequence; D000818:Animals; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry; D008666:Metalloendopeptidases / Q000172:deficiency / Q000378:metabolism*; D051379:Mice; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D021122:Protein Subunits; D008666:Metalloendopeptidases; C491813:Spg7 protein, mouse; C114583:m-AAA proteases; D020558:GTP Phosphohydrolases; C415198:OPA1 protein, human; D000074183:ATPases Associated with Diverse Cellular Activities