Over-expression of plant 14-3-3 proteins in tobacco: enhancement of the plasmalemma K+ conductance of mesophyll cells.
Two cDNA clones encoding 14-3-3 homologous proteins were isolated from Vicia faba. Deduced amino acid sequences share different degrees of homology with other plant 14-3-3 proteins. Both clones, under the control of the CaMV 35S promoter, were transformed into tobacco plants. Immunoblotting showed three different forms of ca. 31, 34, and 37 kDa, indicating a covalent modification of the expressed 14-3-3 proteins. These forms were mainly present in the microsomal fraction. Patch-clamp studies of mesophyll protoplasts of the transformants revealed a strongly enhanced K+ conductance compared to the wild type. This indicates the involvement of 14-3-3 proteins in ion channel regulation, presumably by modulating kinase activities or binding the channel.
Saalbach
G
G
Institut für Pflanzengenetik und Kulturpflanzenforschung, Gatersleben,Germany. saalbchg@ipk-gatersleben.de
Schwerdel
M
M
Natura
G
G
Buschmann
P
P
Christov
V
V
Dahse
I
I
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D007887:Fabaceae / Q000235:genetics*; D015870:Gene Expression; D017136:Ion Transport; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018408:Patch-Clamp Techniques; D010946:Plants, Medicinal; D010947:Plants, Toxic; D015221:Potassium Channels / Q000502:physiology*; D014176:Protein Biosynthesis; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011523:Protoplasts / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D015221:Potassium Channels; D011506:Proteins; D011993:Recombinant Fusion Proteins; D014446:Tyrosine 3-Monooxygenase