The GluTR-binding protein is the heme-binding factor for feedback control of glutamyl-tRNA reductase

eLife

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[1] Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Berlin, Germany;

关键词: tetrapyrrole biosynthesis;    5-aminolevulinic acid synthesis;    GluTR;    heme;    posttranslational regulation;    A. thaliana;   

DOI  :  10.7554/eLife.46300

来源: publisher

【 摘 要 】

10.7554/eLife.46300.001Synthesis of 5-aminolevulinic acid (ALA) is the rate-limiting step in tetrapyrrole biosynthesis in land plants. In photosynthetic eukaryotes and many bacteria, glutamyl-tRNA reductase (GluTR) is the most tightly controlled enzyme upstream of ALA. Higher plants possess two GluTR isoforms: GluTR1 is predominantly expressed in green tissue, and GluTR2 is constitutively expressed in all organs. Although proposed long time ago, the molecular mechanism of heme-dependent inhibition of GluTR in planta has remained elusive. Here, we report that accumulation of heme, induced by feeding with ALA, stimulates Clp-protease-dependent degradation of Arabidopsis GluTR1. We demonstrate that binding of heme to the GluTR-binding protein (GBP) inhibits interaction of GBP with the N-terminal regulatory domain of GluTR1, thus making it accessible to the Clp protease. The results presented uncover a functional link between heme content and the post-translational control of GluTR stability, which helps to ensure adequate availability of chlorophyll and heme.

【 授权许可】

CC BY