A plastid protein crucial for Ca2+-regulated stomatal responses.
* Guard cell movements are regulated by environmental cues including, for example, elevations in extracellular Ca(2+) concentration. Here, the subcellular localization and physiological function of the Ca(2+)-sensing receptor (CAS) protein was investigated. * CAS protein localization was ascertained by microscopic analyses of green fluorescent protein (GFP) fusion proteins and biochemical fractionation assays. Comparative guard cell movement investigations were performed in wild-type and cas loss-of-function mutant lines of Arabidopsis thaliana. Cytoplasmic Ca(2+) dynamics were addressed in plants expressing the yellow cameleon reporter protein YC3.6. * This study identified CAS as a chloroplast-localized protein that is crucial for proper stomatal regulation in response to elevations of external Ca(2+). CAS fulfils this role through modulation of the cytoplasmic Ca(2+) concentration. * This work reveals a novel role of the chloroplast in cellular Ca(2+) signal transduction.
Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
Stefan
S
Weinl
Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
Katrin
K
Held
Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
Kathrin
K
Schlücking
Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
Leonie
L
Steinhorst
Institut für Biochemie und Biotechnologie der Pflanzen, Universität Münster, Hindenburgplatz 55, 48143 Münster, Germany.
Sebastian
S
Kuhlgert
Institut für Biochemie und Biotechnologie der Pflanzen, Universität Münster, Hindenburgplatz 55, 48143 Münster, Germany.
Michael
M
Hippler
Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
Jörg
J
Kudla
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D002458:Cell Fractionation; D017124:Conserved Sequence; D003593:Cytoplasm / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000032:analysis; D054046:Plant Stomata / Q000378:metabolism* / Q000502:physiology; D044169:Receptors, Calcium-Sensing / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D020539:Sequence Analysis, Protein; D015398:Signal Transduction / Q000235:genetics; D020524:Thylakoids / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D014026:Nicotiana / Q000235:genetics / Q000648:ultrastructure
D029681:Arabidopsis Proteins; C532740:CAS protein, Arabidopsis; D002135:Calcium-Binding Proteins; D044169:Receptors, Calcium-Sensing; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D002118:Calcium