Molecular and physiological characterisation of a 14-3-3 protein from lily pollen grains regulating the activity of the plasma membrane H+ ATPase during pollen grain germination and tube growth.
A 14-3-3 protein has been cloned and sequenced from a cDNA library constructed from mRNAs of mature pollen grains of Lilium longiflorum Thunb. Monoclonal antibodies (MUP 5 or MUP 15) highly specific against 14-3-3 proteins recognised a 30-kDa protein in the cytoplasmic fraction of many various lily tissues (leaves, bulbs, stems, anther filaments, pollen grains, stigmas) and in other plants (Arabidopsis seedlings, barley recombinant 14-3-3). In addition, 14-3-3 proteins were detected in a microsomal fraction isolated from pollen grains and tubes, and the amount of membrane-bound 14-3-3 proteins as well as the amount of the plasma membrane (PM) H+ ATPase increased during germination of pollen grains and tube growth. No change was observed in the cytoplasmic fraction. A further increase in the amount of 14-3-3 proteins in the microsomal fraction was observed when pollen grains were incubated in germination medium containing 1 microM fusicoccin (FC) whereas the number of 14-3-3s in the cytoplasmic fraction decreased. Fusicoccin also protected membrane-bound 14-3-3 proteins from dissociation after washing with the chaotropic salt KI. Furthermore, FC stimulated the PM H+ ATPase activity, the germination frequency and the growth rate of pollen tubes, thus indicating that a modulation of the PM H+ ATPase activity by interaction with 14-3-3 proteins may regulate germination and tube growth of lily pollen.
Pertl
H
H
Institut für Pflanzenphysiologie, Universität Salzburg, Austria.
Himly
M
M
Gehwolf
R
R
Kriechbaumer
R
R
Strasser
D
D
Michalke
W
W
Richter
K
K
Ferreira
F
F
Obermeyer
G
G
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D002462:Cell Membrane / Q000201:enzymology; D003593:Cytoplasm / Q000378:metabolism; D006027:Glycosides / Q000494:pharmacology; D006801:Humans; D019668:Liliaceae / Q000201:enzymology / Q000502:physiology*; D008861:Microsomes / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D011058:Pollen / Q000187:drug effects / Q000254:growth & development*; D011193:Potassium Iodide / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000502:physiology*
D048948:14-3-3 Proteins; D000911:Antibodies, Monoclonal; D006027:Glycosides; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D011193:Potassium Iodide; C007808:fusicoccin; D014446:Tyrosine 3-Monooxygenase; D006180:Proton-Translocating ATPases