title: Where and how does phototropin transduce light signals in the cell?
abstract: Light plays pivotal roles as an important environmental signal in plant growth and development. In Arabidopsis, phototropin 1 (phot1) and 2 (phot2) are the photoreceptors that mediate phototropism, chloroplast relocation, stomatal opening and leaf flattening, in response to blue light. However, little is known about how phototropins transduce the signals after the light is perceived. Changes induced by blue light in terms of intracellular localization patterns of phot2 in Arabidopsis were examined. Phot2 distributed uniformly in the plasma membrane under dark conditions. Upon irradiation with blue light, some of the phot2 associated with the Golgi apparatus. It was also shown that the kinase domain, but not the photosensory domain, is required for a plasma membrane and Golgi localization. Furthermore a kinase fragment, lacking the photosensory domain, constitutively triggered physiological responses in planta. Thus, the plasma membrane and the Golgi apparatus appear to be the most likely sites for the initial step of phot2 signal transduction. The Golgi apparatus facilitates vesicle trafficking and delivery of membrane proteins to the required locations in the cell. Therefore, this study implicates the regulation of vesicle trafficking by the Golgi apparatus as a mechanism by which phot2 elicits its cellular responses.
authors.affiliation: Division of Photobiology; National Institute for Basic Biology; Okazaki, Japan.
authors.forename: Sam-Geun
authors.initials: SG
authors.lastname: Kong
authors.forename: Akira
authors.initials: A
authors.lastname: Nagatani
references.citation: Cell. 2000 Feb 18;100(4):469-78
references.pmid: 10693763
references.citation: Plant J. 2006 Mar;45(6):994-1005
references.pmid: 16507089
references.citation: Science. 1997 Dec 19;278(5346):2120-3
references.pmid: 9405347
references.citation: Trends Plant Sci. 2002 May;7(5):204-10
references.pmid: 11992825
references.citation: Plant Cell. 2001 May;13(5):993-7
references.pmid: 11424903
references.citation: Plant Cell. 2004 Apr;16(4):887-96
references.pmid: 15031408
references.citation: Plant Physiol. 2004 Jan;134(1):28-31
references.pmid: 14730061
references.citation: Science. 2004 Oct 29;306(5697):862-5
references.pmid: 15514156
references.citation: Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13337-42
references.pmid: 16150710
references.citation: Plant Cell. 2005 Feb;17(2):525-36
references.pmid: 15659621
references.citation: Plant J. 2007 Sep;51(5):862-73
references.pmid: 17662032
references.citation: Plant Cell. 2000 Feb;12(2):225-36
references.pmid: 10662859
references.citation: Nature. 2001 Dec 6;414(6864):656-60
references.pmid: 11740564
references.citation: Plant Cell. 2006 Jul;18(7):1604-16
references.pmid: 16731587
references.citation: Nature. 2007 Jul 26;448(7152):493-6
references.pmid: 17653191
references.citation: Development. 2001 Oct;128(20):4057-67
references.pmid: 11641228
references.citation: Proc Natl Acad Sci U S A. 2001 Jun 5;98(12):6969-74
references.pmid: 11371609
references.citation: New Phytol. 2005 Jan;165(1):29-44
references.pmid: 15720618
references.citation: Science. 2001 Mar 16;291(5511):2138-41
references.pmid: 11251116
references.citation: Science. 1999 Oct 29;286(5441):961-4
references.pmid: 10542152
references.citation: Plant Cell. 2002 Aug;14(8):1723-35
references.pmid: 12172018
references.citation: Nature. 2001 Apr 19;410(6831):952-4
references.pmid: 11309623
references.citation: EMBO J. 1999 Oct 15;18(20):5548-58
references.pmid: 10523299
references.citation: J Biol Chem. 2006 Nov 17;281(46):35520-30
references.pmid: 16973627
references.citation: Trends Plant Sci. 2003 Sep;8(9):424-31
references.pmid: 13678909
references.citation: Proc Natl Acad Sci U S A. 2006 Jun 27;103(26):10134-9
references.pmid: 16777956
references.citation: Cell. 2003 Jan 24;112(2):219-30
references.pmid: 12553910
references.citation: Nature. 2007 Jul 26;448(7152):488-92
references.pmid: 17653190
references.citation: Curr Opin Plant Biol. 2006 Dec;9(6):589-94
references.pmid: 17011816