title: PLGG1, a plastidic glycolate glycerate transporter, is required for photorespiration and defines a unique class of metabolite transporters.
abstract: Photorespiratory carbon flux reaches up to a third of photosynthetic flux, thus contributes massively to the global carbon cycle. The pathway recycles glycolate-2-phosphate, the most abundant byproduct of RubisCO reactions. This oxygenation reaction of RubisCO and subsequent photorespiration significantly limit the biomass gains of many crop plants. Although photorespiration is a compartmentalized process with enzymatic reactions in the chloroplast, the peroxisomes, the mitochondria, and the cytosol, no transporter required for the core photorespiratory cycle has been identified at the molecular level to date. Using transcript coexpression analyses, we identified Plastidal glycolate glycerate translocator 1 (PLGG1) as a candidate core photorespiratory transporter. Related genes are encoded in the genomes of archaea, bacteria, fungi, and all Archaeplastida and have previously been associated with a function in programmed cell-death. A mutant deficient in PLGG1 shows WT-like growth only in an elevated carbon dioxide atmosphere. The mutant accumulates glycolate and glycerate, leading to the hypothesis that PLGG1 is a glycolate/glycerate transporter. This hypothesis was tested and supported by in vivo and in vitro transport assays and (18)O(2)-metabolic flux profiling. Our results indicate that PLGG1 is the chloroplastidic glycolate/glycerate transporter, which is required for the function of the photorespiratory cycle. Identification of the PLGG1 transport function will facilitate unraveling the role of similar proteins in bacteria, archaea, and fungi in the future.
authors: Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences,  Heinrich Heine University, 40225 Düsseldorf,  Germany.
authors: Thea R
authors: TR
authors: Pick
authors: Andrea
authors: A
authors: Bräutigam
authors: Matthias A
authors: MA
authors: Schulz
authors: Toshihiro
authors: T
authors: Obata
authors: Alisdair R
authors: AR
authors: Fernie
authors: Andreas P M
authors: AP
authors: Weber
mesh_terms: D018556:Crops, Agricultural / Q000378:metabolism*; D006016:Glycolates / Q000378:metabolism*; D008027:Light; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010100:Oxygen / Q000378:metabolism*; D018087:Plastids
chemical_list: D006016:Glycolates; D026901:Membrane Transport Proteins; C031149:glycolic acid; D010100:Oxygen
references: New Phytol. 2012 Jan;193(1):81-95
references: 21916894
references: Plant J. 1998 Dec;16(6):735-43
references: 10069079
references: Plant Physiol. 1981 Apr;67(4):666-71
references: 16661733
references: Plant J. 2005 Jun;42(5):618-40
references: 15918878
references: Plant Cell. 1999 May;11(5):781-92
references: 10330465
references: Science. 2003 Aug 1;301(5633):653-7
references: 12893945
references: Plant Physiol. 2003 Jan;131(1):16-26
references: 12529511
references: Plant J. 2006 Jan;45(2):206-24
references: 16367965
references: Planta. 1986 Oct;169(2):228-37
references: 24232555
references: Front Plant Sci. 2012 Feb 28;3:38
references: 22639647
references: Plant J. 1996 Feb;9(2):195-203
references: 8820606
references: FEBS Lett. 2002 Oct 9;529(2-3):215-20
references: 12372603
references: Genome Res. 2004 Jun;14(6):1085-94
references: 15173114
references: Biochim Biophys Acta. 1980 Oct 3;592(3):577-91
references: 6251871
references: Nat Biotechnol. 2000 Nov;18(11):1157-61
references: 11062433
references: Curr Biol. 2012 Jul 10;22(13):1207-12
references: 22704988
references: Plant J. 2003 Aug;35(3):316-31
references: 12887583
references: Plant Physiol. 2008 Sep;148(1):568-79
references: 18599648
references: Plant J. 2003 Mar;33(6):975-87
references: 12631323
references: Proc Natl Acad Sci U S A. 2005 Jun 14;102(24):8633-8
references: 15932943
references: Plant Physiol. 1991 Aug;96(4):1060-9
references: 16668298
references: Proc Natl Acad Sci U S A. 1983 Mar;80(5):1290-4
references: 16593285
references: Plant Physiol. 1993 Mar;101(3):793-799
references: 12231730
references: Nat Biotechnol. 2007 May;25(5):593-9
references: 17435746
references: Plant J. 2007 Jun;50(5):902-10
references: 17461789
references: J Biol Chem. 2007 May 18;282(20):14932-41
references: 17314094
references: Plant Physiol. 2003 Oct;133(2):462-9
references: 14555774
references: Plant Physiol. 2006 Jan;140(1):59-66
references: 16339799
references: Plant Physiol. 1978 Dec;62(6):954-67
references: 16660647
references: Front Plant Sci. 2012 Jan 23;3:7
references: 22645566
references: Nat Genet. 2002 Jul;31(3):255-65
references: 12089522
references: Plant Physiol. 2008 May;147(1):41-57
references: 18354039
references: Plant Methods. 2008 Apr 28;4:7
references: 18442406
references: Plant Physiol. 1986 Feb;80(2):390-5
references: 16664631
references: Proc Natl Acad Sci U S A. 1998 Dec 8;95(25):14863-8
references: 9843981
references: Plant Cell. 2008 Oct;20(10):2848-59
references: 18952776
references: Plant Cell. 2005 Aug;17(8):2413-20
references: 15980259
references: Plant Cell Physiol. 2012 Jan;53(1):125-34
references: 22180599
references: Biochim Biophys Acta. 2006 Dec;1763(12):1496-510
references: 17046077