title: Identification of lily pollen 14-3-3 isoforms and their subcellular and time-dependent expression profile.
abstract: 14-3-3 proteins are major regulators in plant development and physiology including primary metabolism and signal transduction pathways, typically via a phosphorylation-dependent interaction with a target protein. Four full-length 14-3-3 isoforms were identified in pollen grains of Lilium longiflorum by screening of a cDNA library and RACE (rapid amplification of cDNA ends)-PCR. Mass spectrometry analysis of partially purified 14-3-3s confirmed the presence of the four isoforms but also indicated the presence of additional, less abundant 14-3-3 isoforms in lily pollen. Separation of partially purified 14-3-3 proteins by two-dimensional gel electrophoresis resulted in nine spots that mainly contained the four major 14-3-3 isoforms. In a first step to examine putative physiological roles of specific 14-3-3 isoforms, their subcellular expression profile during pollen germination and tube growth was monitored using a characterized set of antibodies against 14-3-3 proteins with distinct crossreactivity. The abundance profile of 14-3-3 proteins associated with the cytosol, endomembranes (tonoplast, endoplasmic reticulum, Golgi, mitochondria) and plasma membrane showed high spatial-temporal dynamics. This indicates different targets of 14-3-3 proteins at different organelles and time points during pollen germination and growth.
authors.affiliation: Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of Salzburg, Billrothstr. 11, A-5020 Salzburg, Austria.
authors.forename: Heidi
authors.initials: H
authors.lastname: Pertl
authors.forename: Simon
authors.initials: S
authors.lastname: Rittmann
authors.forename: Waltraud X
authors.initials: WX
authors.lastname: Schulze
authors.forename: Gerhard
authors.initials: G
authors.lastname: Obermeyer
mesh_terms: D048948:14-3-3 Proteins / Q000302:isolation & purification* / Q000378:metabolism*; D000595:Amino Acid Sequence; D015723:Gene Library; D018525:Germination; D027762:Lilium / Q000254:growth & development / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015388:Organelles; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism; D011058:Pollen / Q000201:enzymology*; D020033:Protein Isoforms / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment / Q000145:classification
chemical_list: D048948:14-3-3 Proteins; D010940:Plant Proteins; D020033:Protein Isoforms