Dual Targeting of Glutathione Reductase to Mitochondria and Chloroplasts

..................................................................................................................................... 4 List of Publications for the thesis............................................................................................. 5 Abbreviations ............................................................................................................................ 7 THE STRUCTURE OF MITOCHONDRIA AND CHLOROPLASTS........................... 8 Cellular structure...................................................................................................................... 8 The mitochondrion.................................................................................................................... 8 The plant mitochondrial proteome.......................................................................................... 9 The chloroplast ........................................................................................................................ 10 The chloroplastic proteome.................................................................................................... 10 EVOLUTION OF THE PLANT CELL .......................................................................... 11 Origin of the plant cell ............................................................................................................ 11 Reduction of the organellar genomes .................................................................................... 12 TARGETING SIGNAL SEQUENCES........................................................................... 14 Evolution of targeting signal sequences ................................................................................ 14 Features of targeting signal sequences .................................................................................. 14 PROTEIN IMPORT INTO MITOCHONDRIA............................................................. 16 Interaction of mitochondrial proteins with cytosolic factors .............................................. 17 Translocase of the outer membrane (TOM)......................................................................... 19 Import receptors ..................................................................................................................... 19 The sorting and assembly machinery (SAM) ....................................................................... 20 The general import pore (GIP) .............................................................................................. 21 Translocase of the inner membrane (TIM) .......................................................................... 22 The TIM23 complex................................................................................................................ 23 The TIM22 complex................................................................................................................ 24 The mitochondrial processing peptidase (MPP) .................................................................. 25 PROTEIN IMPORT INTO CHLOROPLASTS ............................................................. 26 Interaction of chloroplastic proteins with cytosolic factors ................................................ 27 Translocase of the outer envelope membrane (TOC) .......................................................... 28 Translocase of the inner envelope membrane (TIC)............................................................ 30 The stromal processing peptidase (SPP) ............................................................................... 31 DUAL TARGETING........................................................................................................ 31 Specificity of import and mis-targeting of proteins ............................................................. 32 Dual targeting to mitochondria and chloroplasts................................................................. 33 The Dual import system ......................................................................................................... 35 The glutathione reductase targeting signal........................................................................... 37 Domain structure of glutathione reductase targeting signal ............................................... 38 Import of glutathione reductase ............................................................................................ 40 Processing of glutathione reductase ...................................................................................... 43 CONCLUDING REMARKS........................................................................................... 46 ACKNOWLEDGEMENTS.............................................................................................. 48 REFERENCES ................................................................................................................ 49