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Fungal phytochrome chromophore biosynthesis at mitochondria

Streng, Christian 1; Hartmann, Jana; Leister, Kai 1; Krauß, Norbert 2; Lamparter, Tilman 2; Frankenberg-Dinkel, Nicole; Weth, Franco 3; Bastmeyer, Martin 3; Yu, Zhenzhong; Fischer, Reinhard 1
1 Institut für Angewandte Biowissenschaften (IAB), Karlsruher Institut für Technologie (KIT)
2 Botanisches Institut (BOTANIK), Karlsruher Institut für Technologie (KIT)
3 Zoologisches Institut (ZOO), Karlsruher Institut für Technologie (KIT)


Mitochondria are essential organelles because of their function in energy conservation. Here, we show an involvement of mitochondria in phytochrome-dependent light sensing in fungi. Phytochrome photoreceptors are found in plants, bacteria, and fungi and contain a linear, heme-derived tetrapyrrole as chromophore. Linearization of heme requires heme oxygenases (HOs) which reside inside chloroplasts in planta. Despite the poor degree of conservation of HOs, we identified two candidates in the fungus Alternaria alternata. Deletion of either one phenocopied phytochrome deletion. The two enzymes had a cooperative effect and physically interacted with phytochrome, suggesting metabolon formation. The metabolon was attached to the surface of mitochondria with a C-terminal anchor (CTA) sequence in HoxA. The CTA was necessary and sufficient for mitochondrial targeting. The affinity of phytochrome apoprotein to HoxA was 57,000-fold higher than the affinity of the holoprotein, suggesting a “kiss-and-go” mechanism for chromophore loading and a function of mitochondria as assembly platforms for functional phytochrome. Hence, two alternative approaches for chromophore biosynthesis and insertion into phytochrome evolved in plants and fungi.

Verlagsausgabe §
DOI: 10.5445/IR/1000136110
Veröffentlicht am 09.08.2021
DOI: 10.15252/embj.2021108083
Zitationen: 3
Web of Science
Zitationen: 2
Zitationen: 5
Cover der Publikation
Zugehörige Institution(en) am KIT Botanisches Institut (BOTANIK)
Institut für Angewandte Biowissenschaften (IAB)
Institut für Biologische und Chemische Systeme (IBCS)
Karlsruhe School of Optics & Photonics (KSOP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 0261-4189, 1460-2075
KITopen-ID: 1000136110
HGF-Programm 47.14.02 (POF IV, LK 01) Information Storage and Processing in the Cell Nucleus
Erschienen in EMBO Journal
Verlag John Wiley and Sons
Band 40
Heft 17
Seiten Art.-Nr.: e108083
Vorab online veröffentlicht am 13.07.2021
Schlagwörter chromophore; heme; heme oxygenase; metabolon; phytochrome
Nachgewiesen in Dimensions
Web of Science
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