FLU, a negative feedback regulator of tetrapyrrole biosynthesis, is physically linked to the final steps of the Mg(++)-branch of this pathway.
Regulation of tetrapyrrole biosynthesis in higher plants has been attributed to negative feedback control. Two effectors of feedback inhibition have been identified, heme and the FLU protein. Inhibition by heme implicates the Fe-branch via regulation of the initial step of tetrapyrrole synthesis. In the present work a FLU-containing chloroplast membrane complex was identified, that besides FLU comprises the four enzymes catalyzing the final steps of chlorophyll synthesis. The results support the notion that FLU links chlorophyll synthesis and the target of feedback control, glutamyl-tRNA reductase, thereby allowing also the Mg-branch to control the initial step of tetrapyrrole synthesis.
Department of Biology & Zurich-Basel Plant Science Center, ETH Zurich, Universitatstr. 2, CH-8092 Zurich, Switzerland.
Dominika
D
Kauss
Sylvain
S
Bischof
Sandro
S
Steiner
Klaus
K
Apel
Rasa
R
Meskauskiene
D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000378:metabolism*; D055162:Biocatalysis; D002734:Chlorophyll / Q000096:biosynthesis*; D002736:Chloroplasts / Q000378:metabolism; D025461:Feedback, Physiological; D007425:Intracellular Membranes / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism*
D029681:Arabidopsis Proteins; C478633:FLU protein, Arabidopsis; D002734:Chlorophyll; D000445:Aldehyde Oxidoreductases; C067282:glutamyl tRNA reductase; D008274:Magnesium